Answer:
B. Increasing atmospheric carbon dioxide will cause mean global temperature to increase by 2 degrees Celsius over the next century.
Explanation:
By definition, a hypothesis is a tentative statement or prediction with little or no experimental test. Hypotheses are always formulated such that they can be rejected if experimental findings are against them.
Hypotheses are predictive and as such, the tone is often in future tense.
From the available options, only option B sound predictive of what might happen in the future.
Hence, the correct option is B.
At what temperature in K will 4.00 moles of gas occupy a volume of 12.0 L at a pressure of 5.60 atm?
Answer:
The answer to your question is T = 204.9°K
Explanation:
Data
Temperature = T = ?
number of moles = n = 4
Volume = V = 12 L
Pressure = P = 5.60 atm
constant of gases = 0.082 atm L /mol °K
Process
To solve this problem, use the Ideal Gas Law and solve it for T
Formula
PV = nRT
T = PV / nR
-Substitution
T = (5.60)(12)/(4)((0.082)
-Simplification
T = 67.2 / 0.328
-Result
T = 204.9°K
Considering the ideal gas law, at 204.878 K will 4.00 moles of gas occupy a volume of 12.0 L at a pressure of 5.60 atm.
An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:
P×V = n×R×T
where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas. The universal constant of ideal gases R has the same value for all gaseous substances. The numerical value of R will depend on the units in which the other properties are worked.
In this case, you know:
P= 5.60 atmV= 12 Ln= 4 molesR= 0.082 [tex]\frac{atmL}{molK}[/tex]T=?Replacing in the ideal gas law:
5.60 atm×12 L = 4 moles×0.082[tex]\frac{atmL}{molK}[/tex]×T
Solving:
[tex]T=\frac{5.60 atmx12 L}{4 moles x 0.082 \frac{atmL}{molK}}[/tex]
T=204.878 K
Finally, at 204.878 K will 4.00 moles of gas occupy a volume of 12.0 L at a pressure of 5.60 atm.
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Convert 6mol NO2 into grams Convert 800 grams of LiO into moles! Convert 4500 grams of SO2 into molecules! Convert 30 mol H2O into grams! Convert 8mol CO into grams!
Answer:
1. 276 g of NO₂
2. 34.8 moles of LiO
3. 4.23×10²⁵ molecules of SO₂
4. 540 g of H₂O
5. 224 g CO
Explanation:
Let's define the molar mass of the compound to define the moles or the grans of each.
Molar mass . moles = Mass
Mass (g) / Molar mass = Moles
1. 6 mol . 46 g / 1 mol = 276 g of NO₂
2. 800 g . 1mol / 22.94 g = 34.8 moles of LiO
3. To determine the number of molecules, we convert the mass to moles and then, we use the NA (1 mol contains 6.02×10²³ molecules)
4500 g . 1mol / 64.06 g = 70.2 moles of SO₂
70.2 mol . 6.02×10²³ molecules / 1 mol = 4.23×10²⁵ molecules of SO₂
4. 30 mol . 18g / 1 mol = 540 g of H₂O
5. 8 mol . 28g / 1mol = 224 g CO
A compound is 92.2% Carbon and 7.76% Hydrogen. The formula mass of the compound is 78.1 g. Calculate the empirical formula and molecular formula of the compound.
Answer:
The answer to your question is empirical formula = CH
molecular formula = C₆H₆
Explanation:
Data
Carbon 92.2%
Hydrogen 7.76%
Formula mass = 78.1 g
Process
1.- Express the percents as grams
Carbon 92.2 g
Hydrogen 7.76 g
2.- Convert the grams to moles
Carbon 12 g ---------------- 1 mol
92.2 g ------------- x
x = (92.2 x 1)/12
x = 7.68 moles
Hydrogen 1 g ------------------ 1 mol
7.76 g ------------- x
x = 7.76 moles
3.- Divide by the lowest number of moles
Carbon 7.68 / 7.68 = 1
Hydrogen 7.76 / 7.68 = 1.01
4.- Write the empirical formula
CH
5.- Calculate the molecular weight of the empirical formula
CH = 12 + 1 = 13
6.- Divide the molecular weight by the molecular weight of the empirical formula
78.1 / 13 = 6
7.- Write the molecular formula
6(CH) = C₆H₆
The empirical formula of the compound is CH. The molecular formula of the compound is [tex]\rm \bold C_6H_6[/tex]
A molecular formula has been the one that represents the exact number of atoms in a compound. The empirical formula has been able to represent the whole number ratio of atoms present in a compound.
The given compound has 92.2% Carbon and 7.76% Hydrogen. The weight will be:
Carbon = 92.2 g
Hydrogen = 7.76 g
From the weight, the moles of elements in the compound can be calculated.
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of carbon = [tex]\rm \dfrac{92.2}{12}[/tex]
Moles of carbon = 7.76 moles
Moles of hydrogen = weight of hydrogen
Moles of hydrogen = 7.76 moles
For the empirical formula, divide the moles of each element to the nearest mole number;
Carbon = [tex]\rm \dfrac{7.76}{7.76}[/tex]
Carbon = 1
Hydrogen = [tex]\rm \dfrac{7.76}{7.76}[/tex]
Hydrogen = 1
Thus, the empirical formula of the compound will be CH.
For finding the molecular formula, the molecular weight from the empirical formula has been divided with the molecular weight of the compound to find the number of atoms.
Molecular weight of empirical formula = weight of carbon + weight of hydrogen
Molecular weight of empirical formula = 12 + 1
Molecular weight of empirical formula = 13 grams
Molecular mass of compound = 78.1 grams.
Number of atoms of each element = [tex]\rm \dfrac{78.1}{13}[/tex]
Number of atoms of each element = 6
Thus, the molecular formula of the compound is [tex]\rm C_6H_6[/tex].
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Consider the following system at equilibrium:D(aq)+E(aq)<=>F(aq)Classify each of the following actions by whether it causes a leftward shift, a rightward shift, or no shift in the direction of the net reaction.Increase DIncrease EIncrease FDecrease DDecrease EDecrease FTriple D and reduce E to one thirdTriple both E and F
Explanation:
D(aq) + E(aq) <=> F(aq)
This question is based on Le Chatelier's principle.
Le Chatelier's principle is an observation about chemical equilibria of reactions. It states that changes in the temperature, pressure, volume, or concentration of a system will result in predictable and opposing changes in the system in order to achieve a new equilibrium state.
Increase D
D is a reactant. if we add reactants to the system, equilibrium will be shifted to the right to in order to maintain equilibrium by producing more products.
Increase E
E is a reactant. if we add reactants to the system, equilibrium will be shifted to the right to in order to maintain equilibrium by producing more products.
Increase F
F is a product. If we add additional product to a system, the equilibrium will shift to the left, in order to produce more reactants. The reaction would shift to the left.
Decrease D
if we remove reactants from the system, equilibrium will be shifted to the left.
Decrease E
if we remove reactants from the system, equilibrium will be shifted to the left.
Decrease F
if we remove products from the system, equilibrium will be shifted to the right to in order to maintain equilibrium by producing more products.
Triple D and reduce E to one third
no shift in the direction of the net reaction, Both changes cancels each other.
Triple both E and F
no shift in the direction of the net reaction, Both changes cancels each other.
What is the most important reason to consider ethics when conducting
experiments?
O
A. The scientific results would not be believable if they were obtained
unethically.
O
B. It is important that people are not harmed for the sake of science.
O
C. A general sense of ethics ensures that everyone is aware of what's
right and what's wrong.
O
D. Scientists would not be able to get funding if their experiments
were not ethical.
Answer:
B. It is important that people are not harmed for the sake of science.
Explanation:
Ethical principles stress the need to do good and cause no harm.A researcher is therefore required to;
obtain an informed consent from the participantsminimize or eliminate risk of harm to participantsprotect the anonymity and confidentiality of participantsApply no deceptive techniquesallow the right to withdraw from the study by a participantAnswer:
It is important that people are not harmed for the sake of science.
Explanation:
The molar mass of an unknown gas was measured by an effusion experiment. It was found that it took 60 s for the gas to effuse, whereas nitrogen gas required 48 s. The molar mass of the gas is ________
The molar mass of the unknown gas can be determined by comparing its effusion rate to the effusion rate of a known gas, such as nitrogen gas. According to Graham's law of effusion, the rate of effusion is inversely proportional to the square root of the molar mass of the gas. Let's set up a proportion to find the molar mass of the unknown gas.
Explanation:The molar mass of the unknown gas can be determined by comparing its effusion rate to the effusion rate of a known gas, such as nitrogen gas. In this case, it took 60 seconds for the unknown gas to effuse, whereas nitrogen gas required 48 seconds. According to Graham's law of effusion, the rate of effusion is inversely proportional to the square root of the molar mass of the gas. Using this information, we can set up a proportion to find the molar mass of the unknown gas.
Let's assume the molar mass of the unknown gas is represented by 'X'. The proportion can be set up as follows:
(rate of unknown gas)/(rate of nitrogen gas) = sqrt(molar mass of nitrogen gas)/sqrt(molar mass of unknown gas)
Substituting the known values, we have:
(60 s)/(48 s) = sqrt(28.01 g/mol)/sqrt(X)
Solving for X, the molar mass of the unknown gas is approximately 37.07 g/mol.
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Argon, which comprises almost 1 percent of the atmosphere, is approximately 27 times more abundant than CO2, but does not contribute to global warming. Which explanation accounts for this fact
Explanation:
Argon, an element comprises of almost 1 percent in the Earth’s atmosphere, is approximately 27 times more abundant than CO2, is not a greenhouse gas. The reason that it is not a greenhouse gas or not contribute in global warming is that it is largely transparent to the wavelengths of light that is responsible for trapping heat that is similar to that of oxygen, nitrogen and other gasesArgon is not able to form large and complex molecules that are enough to block infrared light, which is generally done by greenhouse gases such as carbon dioxide and methane also.Determine the volume of SO2 (at STP) formed from the reaction of 96.7 g of FeS2 and 55.0 L of O2 (at 398 K and 1.20 atm). The molar mass of FeS2 is 119.99 g/mol. 4 FeS2(s) + 11 O2(g) → 2 Fe2O3(s) + 8 SO2(g)
Answer: 32.9 Liters
Explanation:
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]
1. moles of [tex]FeS_2=\frac{96.7g}{119.99g/mol}=0.806mol[/tex]
2. moles of [tex]O_2[/tex]
[tex]PV=nRT[/tex]
P = pressure of the gas = 1.20 atm
R = Gas constant = [tex]0.0821\text{ L atm }mol^{-1}K^{-1}[/tex]
T = temperature of the gas = [tex]398K[/tex]
[tex]1.20\times 55.0=n\times 0.0821\times 398[/tex]
[tex]n=2.02[/tex]
[tex]4FeS_2(s)+11O_2(g)\rightarrow 2Fe_2O_3(s)+8SO_2(g)[/tex]
According to stoichiometry:
11 moles of oxygen reacts with 4 moles of [tex]FeS_2[/tex]
Thus 2.02 moles of oxygen reacts with =[tex]\frac{4}{11}\times 2.02=0.73[/tex] moles of [tex]FeS_2[/tex]
Thus oxygen acts as limiting reagent and [tex]FeS_2[/tex] is excess reagent.
As 11 moles of oxygen gives = 8 moles of [tex]SO_2[/tex]
2.02 moles of oxygen gives =[tex]\frac{8}{11}\times 2.02=1.47[/tex] moles of [tex]SO_2[/tex]
[tex]PV=nRT[/tex]
P = pressure of the gas = 1 atm (at STP)
R = Gas constant = [tex]0.0821\text{ L atm }mol^{-1}K^{-1}[/tex]
T = temperature of the gas = [tex]273K[/tex] (at STP)
[tex]1\times V=1.47\times 0.0821\times 273[/tex]
[tex]V=32.9L[/tex]
Thus volume of [tex]SO_2[/tex] (at STP) formed from the reaction is 32.9 L
The volume of SO₂ formed from the reaction at STP is 32.92 L
From the question,
We are to determine the volume of SO₂ formed from the reaction
The given balanced chemical equation for the reaction is
4FeS₂(s) + 11O₂(g) → 2Fe₂O₃(s) + 8SO₂(g)
This means,
4 moles of FeS₂ reacts with 11 moles of oxygen to produce 2 moles of Fe₂O₃ and 8 moles of SO₂
First, we will determine the number of moles of each reactant present
For FeS₂Mass = 96.7 g
From the formula
[tex]Number\ of\ moles =\frac{Mass}{Molar\ mass}[/tex]
Molar mass of FeS₂ = 119.99 g/mol
∴ Number of moles of FeS₂ present =[tex]\frac{96.7}{119.99}[/tex]
Number of moles of FeS₂ present = 0.8059 mole
For O₂
Using the formula
PV = nRT
[tex]n =\frac{PV}{RT}[/tex]
Putting the given parameters into the formula, we get
[tex]n = \frac{1.2 \times 55.0}{0.08206 \times 398}[/tex]
[tex]n = \frac{66}{32.65988}[/tex]
n = 2.0208 moles
Since,
4 moles of FeS₂ reacts with 11 moles of oxygen to produce 8 moles of SO₂
Then,
[tex]\frac{2.0208 \times 4}{11}[/tex] moles of FeS₂ will react with 2.0208 moles of oxygen to produce [tex]\frac{2.0208 \times 4}{11} \times 2[/tex] moles of SO₂
That is,
0.7348 moles of FeS₂ will react with 2.0208 moles of oxygen to produce 1.4697 moles of SO₂
∴ Number of moles of SO₂ formed is 1.4697 moles
Now for the volume of SO₂ formed at STP
Since
1 mole of a gas has a volume of 22.4 L at STP
Then
1.4697 moles of the SO₂ will have a volume of 1.4697 × 22.4 L
1.4697 × 22.4 L = 32.92L
Hence, the volume of SO₂ formed from the reaction at STP is 32.92 L
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The normal boiling point of a certain liquid is , but when of urea are dissolved in of , it is found that the solution boils at instead. Use this information to calculate the molal boiling point elevation constant of .
Answer:
The molal boiling point elevation constant (Kb) is calculated by dividing the change in boiling point (∆Tb) by the molality of the solution (m)
Explanation:
Kb = ∆Tb/m
Kb is the molal boiling point elevation constant of the liquid
∆Tb is the change in boiling point. It is calculated by subtracting the initial boiling point of the liquid from the final boiling point of the solution.
m is the molality of the solution. It is calculated by dividing the number of moles of urea (number of moles of urea is calculated by dividing the mass in grams of urea by its molecular weight) by the mass of the liquid in kilograms.
13. What is the total pressure inside the container
Answer: The total pressure inside the container is 77.9 kPa
Explanation:
Dalton's law of partial pressure states that the total pressure of the system is equal to the sum of partial pressure of each component present in it.
To calculate the total pressure inside the container, we use the law given by Dalton, which is:
[tex]P_T=p_{N_2}+p_{O_2}+p_{Ar}[/tex]
We are given:
Vapor pressure of oxygen gas, [tex]p_{O_2}[/tex] = 40.9 kPa
Vapor pressure of nitrogen gas, [tex]p_{N_2}[/tex] = 23.3 kPa
Vapor pressure of argon, [tex]p_{Ar}[/tex] = 13.7 kPa
Putting values in above equation, we get:
[tex]p_T=23.3+40.9+13.7\\\\p_{T}=77.9kPa[/tex]
Hence, the total pressure inside the container is 77.9 kPa
If the detergent requires using 0.61 kg detergent per load of laundry, determine what percentage (by mass) of the detergent should be sodium carbonate in order to completely precipitate all of the calcium and magnesium ions in an average load of laundry water.
Here is the full question.
Sodium carbonate is often added to laundry detergents to soften hard water and make the detergent more effective. Suppose that a particular detergent mixture is designed to soften hard water that is 3.8×10−3M in Ca2+ and 1.1×10−3M in Mg2+ and that the average capacity of a washing machine is 24.5 gallons of water. 1gallon=3.785L
If the detergent requires using 0.61 kg detergent per load of laundry, determine what percentage (by mass) of the detergent should be sodium carbonate in order to completely precipitate all of the calcium and magnesium ions in an average load of laundry water.
Answer:
7.90%
Explanation:
The equation for the reaction can be written as:
[tex]Na_2CO_3+Ca^{2+} ---------> CaCO_3(s) +2Na^+[/tex]
[tex]Na_2CO_3+Mg^{2+} ---------> MgCO_3(s) +2Na^+[/tex]
Molar mass of [tex]Na_2CO_3[/tex] = 106 g/mol
1.00 gallon of water = 3.785 L
∴ 24.5 gallons of water = 24.5 × 3.785
= 92.7325 L
mass precipitate = [tex][(3.8*10^{-3})+(1.1*10^{-3})]\frac{mol}{L} *92.7325*\frac{106g}{mol}[/tex]
mass precipitate = 48.162605
mass precipitate = 48.2 g
mass % = [tex]\frac{mass ofprecipitate}{mass of detergent} *100%[/tex]%
mass % = [tex]\frac{48.2g}{0.61kg}*\frac{1kg}{1000g}*100[/tex]%
mass % = 7.901639344
mass % = 7.90 %
The percentage (by mass) of the detergent should be 7.90%.
Calculation of the percentage:Since 3.8×10−3M in Ca2+ and 1.1×10−3M in Mg2+ and that the average capacity of a washing machine is 24.5 gallons of water. 1gallon=3.785L
The molar mass of Na_2CO_3 is 106g/mol
Since 1.00 gallon of water = 3.785 L
so, for 24.5 gallons of water, it is
= 24.5 × 3.785
= 92.7325 L
Now mass precipitate is
= ((3.8*10^-3) * (1.1*10^-3) * 92.7325 * 106g/mol
= 48.162605
= 48.2g
Now the mass percentage is
= mass of precipitate / mass of detergent
= 48.3g / 0.61 * 1kg / 1000g
= 7.90%
This is an incomplete question. Please find the full question below.
Sodium carbonate is often added to laundry detergents to soften hard water and make the detergent more effective. Suppose that a particular detergent mixture is designed to soften hard water that is 3.8×10−3M in Ca2+ and 1.1×10−3M in Mg2+ and that the average capacity of a washing machine is 24.5 gallons of water. 1gallon=3.785L
If the detergent requires using 0.61 kg detergent per load of laundry, determine what percentage (by mass) of the detergent should be sodium carbonate in order to completely precipitate all of the calcium and magnesium ions in an average load of laundry water.
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A saturated solution of Pb(IO3)2 in pure water has a lead ion concentration of 5.0 x 10-5 Molar. What is the Ksp value of Pb(IO3)2? A. 1.0 x 10-5 Molar B. 5.0 x 10-5 Molar C. 1.0 x 10-13 Molar D. 2.5 x 10-13 Molar E. 5 x 10-13 Molar
Answer:
Option (E) is correct
Explanation:
Solubility equilibrium of [tex]Pb(IO_{3})_{2}[/tex] is given as follows-
[tex]Pb(IO_{3})_{2}\rightleftharpoons Pb^{2+}+2IO_{3}^{-}[/tex]
Hence, if solubility of [tex]Pb(IO_{3})_{2}[/tex] is S (M) then-
[tex][Pb^{2+}]=S(M)[/tex] and [tex][IO_{3}^{-}]=2S(M)[/tex]
Where species under third bracket represent equilibrium concentrations
So, solubility product of [tex]Pb(IO_{3})_{2}[/tex] , [tex]K_{sp}=[Pb^{2+}][IO_{3}^{-}]^{2}[/tex]
Here, [tex][Pb^{2+}]=S(M)=5.0\times 10^{-5}M[/tex]
So, [tex][IO_{3}^{-}]=2S(M)=(2\times 5.0\times 10^{-5})M=1.0\times 10^{-4}M[/tex]
So, [tex]K_{sp}=(5.0\times 10^{-5})\times (1.0\times 10^{-4})^{2}=5.0\times 10^{-13}[/tex]
Hence option (E) is correct
Answer:
E) 5 x 10-13 Molar
Explanation:
plato
A chemist needs to know the concentration of some KOH that is in the laboratory. To find this out, the chemist titrates a 50.0 mL sample of the solution with 2.5 M HCl. If it takes 14.7 mL of the HCl to reach the titration endpoint, what is the concentration of the KOH solution
Answer:
0.735M
Explanation:
The balanced equation of reaction is:
HCl + KOH ===> KCl + H2O
Using titration equation of formula
CAVA/CBVB = NA/NB
Where NA is the number of mole of acid = 1 (from the balanced equation of reaction)
NB is the number of mole of base = 1 (from the balanced equation of reaction)
CA is the concentration of acid = 2.5M
CB is the concentration of base = to be calculated
VA is the volume of acid = 14.7mL
VB is the volume of base = 50mL
Substituting
2.5×14.7/CB×50 = 1/1
Therefore CB =2.5×50×1/14.7×1
CB= 0.735M
You take an aspirin tablet (a compound consisting solely of carbon, hydrogen, and oxygen) with a mass of 1.00 g, burn it in air, and collect 2.20 g of carbon dioxide and 0.400 g water. The molar mass of aspirin is between 170 and 190 g/mol. The molecular formula of aspirin is
Answer:
The formula of aspirin = [tex]C_9H_8O_4[/tex]
Explanation:
Mass of water obtained = 0.400
Molar mass of water = 18 g/mol
Moles of [tex]H_2O[/tex] = 0.400 g /18 g/mol = 0.0222 moles
2 moles of hydrogen atoms are present in 1 mole of water. So,
Moles of H = 2 x 0.0222 = 0.0444 moles
Molar mass of H atom = 1.008 g/mol
Mass of H in molecule = 0.0444 x 1.008 = 0.0448 g
Mass of carbon dioxide obtained = 2.20 g
Molar mass of carbon dioxide = 44.01 g/mol
Moles of [tex]CO_2[/tex] = 2.20 g /44.01 g/mol = 0.05 moles
1 mole of carbon atoms are present in 1 mole of carbon dioxide. So,
Moles of C = 0.05 moles
Molar mass of C atom = 12.0107 g/mol
Mass of C in molecule = 0.05 x 12.0107 = 0.6005 g
Given that the aspirin acid only contains hydrogen, oxygen and carbon. So,
Mass of O in the sample = Total mass - Mass of C - Mass of H
Mass of the sample = 1.00 g
Mass of O in sample = 1.00 - 0.6005 - 0.0448 = 0.3547 g
Molar mass of O = 15.999 g/mol
Moles of O = 0.3547 / 15.999 = 0.0222 moles
Taking the simplest ratio for H, O and C as:
0.0444 : 0.0222 : 0.05
= 8 : 4 : 9
The empirical formula is = [tex]C_9H_8O_4[/tex]
Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.
Thus,
Molecular mass = n × Empirical mass
Where, n is any positive number from 1, 2, 3...
Mass from the Empirical formula = 9×12 + 8×1 + 16×4= 180 g/mol
The molar mass of aspirin is between 170 and 190 g/mol
So,
Molecular mass = n × Empirical mass
170 < n × 180 < 190
⇒ n = 1
The formula of aspirin = [tex]C_9H_8O_4[/tex]
The molecular formula for aspirin can be determined through the quantities of CO2 and H2O produced by burning it. This involves calculating the quantities of each element present and obtaining an empirical formula that must be scaled to match the molar mass of aspirin. Through this process, aspirin's molecular formula is found to be C9H8O4.
Explanation:The empirical formula of aspirin can be determined by understanding the quantity of each element present in the provided quantities of Carbon Dioxide (CO2) and water (H2O) produced by burning the aspirin. From the 2.20 g of CO2, the amount of carbon is calculated to be: mass CO2 x (atomic mass of C/molar mass of CO2). Similarly, from the 0.400 g of water, the quantity of hydrogen is calculated to be: mass H2O x (2 x atomic mass of H/molar mass of H2O). The balance of the original aspirin's 1.00 g mass constitutes oxygen.
Using atomic masses (C = 12.01 g/mol, H = 1.008 g/mol, O = 16.00 g/mol), you generate the empirical formula with the simplest ratio of these elements. However, this formula will not match the molecular mass of 180.15 amu for aspirin. Therefore, a multiple is required to transform the empirical formula into the molecular formula. The required multiple is calculated as (molar mass of aspirin / molar mass of empirical formula).
Applying these calculations and steps reveals that the molecular formula for aspirin is indeed C9H8O4.
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"In carrying out a titration of a hydrochloric acid solution with a standard sodium hydroxide solution, a student went beyond the end point before reading the volume on the burette. That is, the volume used was larger than the volume required to reach the end point. How will this error affect the calculated concentration of the hydrochloric acid?"
Answer:
The calculated concentration of HCl will be less than actual.
Explanation:
Suppose during titration, the HCl was taken in burette and the NaOH in the volumetric flask.
Now we will use equivalence formula for the calculation of concentration of HCl.
[tex]N_{1} V_{1} = N_{2} V_{2}[/tex]
Where L.H.S is for hydrochloric acid and R.H.S is for sodium hydroxide. The terms N and V represent normality and volume respectively.
If we calculate for
[tex]N_{1} = \frac{N_{2}V_{2} }{V_{1} }[/tex]
We see that if the volume of the HCl is greater then the concentration of the HCl will be reduced.
The error will cause the concentration of the hydrochloric acid to be underestimated.
The concentration of a solution is calculated from the ratio of the number of moles of the solutes and that of the volume of the solution.
Mathematically; concentration = mole/volume
Thus, with the number of moles being constant, the higher the volume of the solution, the lower the concentration that would be derived and vice versa.
This means that any volume that exceeds that of the accurate endpoint will cause the concentration to be underestimated and below the endpoint, the concentration would be overestimated.
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A 100.0g sample of tin is heated to 100.0 oC (Celsius) and is placed in a coffee cup calorimeter containing 150. g of water at 25.0 oC. After the metal cools, the final temperature of the metal and the water is 27.4 oC. Calculate the specific heat capacity of tin from these experimental data, assuming that no heat escapes to the surroundings or is transferred to the calorimeter. Specific heat of water
Explanation:
It is known that specific heat of water is 4.184 [tex]J/g^{o}C[/tex] and atomic mass of tin is 118.7 g/mol. For the given situation,
[tex]Q_{lost} = Q_{gained}[/tex]
Let us assume that,
[tex]m_{1}[/tex] = mass of Sn
[tex]m_{2}[/tex] = mass of [tex]H_{2}O[/tex]
Therefore, heat energy expression for heat lost and gained is as follows.
[tex]Q_{lost} = Q_{gained}[/tex]
[tex]m_{1}C_{1}(T_{2} - T_{1}) = m_{2}C_{2}(T_{1} - T_{2})[/tex]
[tex]100 g \times C_{1} \times (100^{o}C - 27.4^{o}C) = 150 g \times 4.184 /g^{o}C \times (27.4^{o}C - 25^{o}C)[/tex]
[tex]7260C_{1} = 150 \times 4.184 \times 2.4[/tex]
[tex]C_{1} = \frac{1506.24}{7260}[/tex]
= 0.207 [tex]J/g^{o}C[/tex]
For, 118.7 g the specific heat of tin will be calculated as follows.
[tex]C_{1} = 0.207 J/g^{o}C \times 118.7 g[/tex]
= 24.5 [tex]J/mol^{o}C[/tex]
Thus, we can conclude that specific heat of tin is 24.5 [tex]J/mol^{o}C[/tex].
To calculate the specific heat capacity of the metal, we can use the equation q = m * c * ΔT, where q is the heat transferred, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. By using the known temperatures and masses of the metal and water, we can solve for the specific heat capacity of the metal.
Explanation:To calculate the specific heat capacity of the metal, we can use the equation q = m * c * ΔT, where q is the heat transferred, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. In this case, we know the initial and final temperatures of the metal and water, as well as the masses of the metal and water. We can rearrange the equation to solve for the specific heat capacity of the metal, c.
We can start by calculating the heat transferred from the metal to the water. The heat transferred to the water can be calculated using the equation q_water = m_water * c_water * ΔT_water, where m_water is the mass of the water, c_water is the specific heat capacity of water, and ΔT_water is the change in temperature of the water.
Next, we can calculate the heat transferred from the metal to the water using the equation q_metal = m_metal * c_metal * ΔT_metal, where m_metal is the mass of the metal, c_metal is the specific heat capacity of the metal, and ΔT_metal is the change in temperature of the metal.
Since the metal and water reach the same final temperature, we can set q_water equal to q_metal and solve for the specific heat capacity of the metal, c_metal.
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A total of 2.00 molmol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 137 gg of solution. The reaction caused the temperature of the solution to rise from 21.00 to 24.70 ∘C∘C. What is the enthalpy of this reaction? Assume that no heat is lost to the surroundings or to the coffee cup itself and that the specific heat of the solution is the same as that of pure water.
Answer : The enthalpy of this reaction is, 1.06 kJ/mol
Explanation :
First we have to calculate the heat produced.
[tex]q=m\times c\times (T_2-T_1)[/tex]
where,
q = heat produced = ?
m = mass of solution = 137 g
c = specific heat capacity of water = [tex]4.18J/g^oC[/tex]
[tex]T_1[/tex] = initial temperature = [tex]21.00^oC[/tex]
[tex]T_2[/tex] = final temperature = [tex]24.70^oC[/tex]
Now put all the given values in the above formula, we get:
[tex]q=137g\times 4.18J/g^oC\times (24.70-21.00)^oC[/tex]
[tex]q=2118.842J=2.12kJ[/tex]
Now we have to calculate the enthalpy of this reaction.
[tex]\Delta H=\frac{q}{n}[/tex]
where,
[tex]\Delta H[/tex] = enthalpy change = ?
q = heat released = 2.12 kJ
n = moles of compound = 2.00 mol
Now put all the given values in the above formula, we get:
[tex]\Delta H=\frac{2.12kJ}{2.00mole}[/tex]
[tex]\Delta H=1.06kJ/mol[/tex]
Thus, the enthalpy of this reaction is, 1.06 kJ/mol
What is the empirical formula of a compound composed of 3.25% hydrogen ( H ), 19.36% carbon ( C ), and 77.39% oxygen ( O ) by mass? Insert subscripts as needed.
Answer : The empirical of the compound is, [tex]C_1H_2O_3[/tex]
Solution : Given,
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of C = 19.36 g
Mass of H = 3.25 g
Mass of O = 77.39 g
Molar mass of C = 12 g/mole
Molar mass of H = 1 g/mole
Molar mass of O = 16 g/mole
Step 1 : convert given masses into moles.
Moles of C = [tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{19.36g}{12g/mole}=1.613moles[/tex]
Moles of H = [tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{3.25g}{1g/mole}=3.25moles[/tex]
Moles of O = [tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{77.39g}{16g/mole}=4.837moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C = [tex]\frac{1.613}{1.613}=1[/tex]
For H = [tex]\frac{3.25}{1.613}=2.01\approx 2[/tex]
For o = [tex]\frac{4.837}{1.613}=2.99\approx 3[/tex]
The ratio of C : H : O = 1 : 2 : 3
The mole ratio of the element is represented by subscripts in empirical formula.
The Empirical formula = [tex]C_1H_2O_3[/tex]
Therefore, the empirical of the compound is, [tex]C_1H_2O_3[/tex]
The empirical formula of a compound with 3.25% H, 19.36% C, and 77.39% O by mass is CH2O3, found by converting the mass of each element to moles and then determining the simplest whole number ratio.
Explanation:To determine the empirical formula of a compound composed of 3.25% hydrogen (H), 19.36% carbon (C), and 77.39% oxygen (O) by mass, we first assume a 100 g sample of the compound. This means we would have 3.25 g of H, 19.36 g of C, and 77.39 g of O.
Next, we convert the mass of each element to moles by dividing by their respective molar masses:
Carbon: 19.36 g / 12.01 g/mol = 1.612 molesHydrogen: 3.25 g / 1.008 g/mol = 3.225 molesOxygen: 77.39 g / 16.00 g/mol = 4.837 molesTo find the simplest whole number ratio, we divide each mole value by the smallest number of moles calculated:
Carbon: 1.612 / 1.612 = 1Hydrogen: 3.225 / 1.612 = 2Oxygen: 4.837 / 1.612 = 3The ratios indicate the empirical formula is CH2O3.
Problem Page Question Solid calcium carbonate decomposes into solid calcium oxide and carbon dioxide gas . Write a balanced chemical equation for this reaction.
Answer:
Δ
CaCO3(s) → → CaO (s) + CO2 (g)
Explanation: Calcium Carbonate also known as Limestone will undergo decomposition reaction in the presence of heat to produce Quick-lime and Carbon dioxide.
Answer:
The balanced chemical equation is:
[tex]CaCO_{3}[/tex] → [tex]CaO + CO_{3}[/tex]
Explanation:
The problem said:
Solid calcium carbonate decomposes into solid calcium oxide and carbon dioxide gas.
Corresponde to chemicale equation:
[tex]CaCO_{3}[/tex] → [tex]CaO + CO_{3}[/tex]
A chemical reaction must be based on the law of the conservation of matter, which implies that matter is not created or destroyed but transformed. Therefore, the same amount of each atom must be involved in the reagents and products.
this reaction have:
Reagents.
Ca = 1C = 1O = 3Products.
Ca = 1C = 1O = 3∴ This equation is balanced.
During digestion, hydrochloric acid (HCl) lowers the stomach's pH and this causes the enzyme pepsinogen to be converted to its active form, called pepsin. Pepsin is a proteolytic enzyme, which means it cleaves (breaks) peptide bonds assocciated with food particles. The enzyme pepsin can also cleave pepsinogen into pepsin, and this causes the rate at which pepsinogen is converted to pepsin to increase. This is an example of:
Answer:
Catalysis
Explanation:
Pepsin is able to break peptide bonds, turning large protein molecules into small peptide chains.
When pepsin acts to break down pepsinogen (inactive form of pepsin), it is accelerating pepsinogen → pepsin reactions, acting as a catalyst, reducing activation energy and favoring proteolytic reactions at a higher rate.
This process of accelerating reactions is characteristic of enzymes and is known as catalysis.
What mass of hydrochloric acid (in grams) can 2.7 g of sodium bicarbonate neutralize? (Hint: Begin by writing a balanced equation for the reaction between aqueous sodium bicarbonate and aqueous hydrochloric acid.)
Answer:
1.17 grams of HCl can neutralize 2.7 grams sodium bicarbonate
Explanation:
Step 1: Data given
Mass of sodium bicarbonate = 2.7 grams
Step 2: The balanced equation
HCl + NaHCO3 ⇔ NaCl + H2O + CO2
Step 3: Calculate moles NaHCO3
moles NaHCO3 =2.7 g / 84 g/mol= 0.032 moles
Step 4: Calculate moles HCl
For 1 mol NaHCO3 we need 1 mol HCl
For 0.032 moles NaHCO3 = 0.032 moles HCl
Step 5: Calculate mass HCl
Mass HCl = moles HCl * molar mass HCl
mass HCl = 0.032 * 36.46 g/mol= 1.17 grams
1.17 grams of HCl can neutralize 2.7 grams sodium bicarbonate
The key process being used here is stoichiometry, which is a core aspect of chemistry that studies the quantitative relationships, or ratios, among reactants in a chemical equation. By writing and analyzing a balanced chemical equation, performing correct conversions, and understanding mole-to-mole ratios, we determine that 2.7 grams of sodium bicarbonate can neutralize approximately 1.17 grams of hydrochloric acid.
Explanation:The subject of this specific problem is stoichiometry, a central concept in chemistry. The first step involves writing a balanced chemical equation between sodium bicarbonate (NaHCO₃) and hydrochloric acid (HCl). The equation will look like this: NaHCO₃ (aq) + HCl (aq) → NaCl (aq) + CO₂ (g) + H₂O (l). This reaction demonstrates that one mole of sodium bicarbonate reacts with one mole of hydrochloric acid.
Next, we'll need to calculate the number of moles of sodium bicarbonate, using the molar mass of sodium bicarbonate, which is approximately 84 g/mol. So, 2.7 g of sodium bicarbonate equals 2.7 g / 84 g/mol = 0.0321 mol.
Since the equation shows a 1:1 ratio, this means that 0.0321 mol of sodium bicarbonate will neutralize the same amount of moles of hydrochloric acid. The molar mass of HCl is about 36.5 g/mol, so multiplying this with the moles of HCl gives the mass: 0.0321 mol * 36.5 g/mol = 1.17 g.
So, 2.7 g of sodium bicarbonate can neutralize 1.17 g of hydrochloric acid.
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The ionization energy of atoms ________. Group of answer choices does not change going down within a group increases going down within a group decreases going down within a group none of the above decreases going across a period
Answer:
decreases going down within a group
Explanation:
Ionization energy of an atom is defined as the energy required to remove electron from the gaseous form the atom. The energy required to remove the highest placed electron in the gaseous form of an atom is referred to as the first ionization energy.
In the periodic table, the first ionization energy decreases down the group because as the principal quantum number increases, the size of the orbital increases and the electron is easier to remove.
In addition, the first ionization energy increases across the period because electrons in the same principal quantum shell do not completely shield the increasing nuclear charge of the protons.
The ionization energy of atoms decreases going down a group on the periodic table and increases going across a period. This is because the atomic radius and the attraction between the nucleus and the outer electrons change.
Explanation:The ionization energy of atoms is the energy required to remove an electron from an atom or ion. As you move down a group on the periodic table, the ionization energy generally decreases. This is because as you go down a group, the atomic radius increases and the outer electrons are further away from the nucleus, making them easier to remove.
On the other hand, as you go across a period from left to right, the ionization energy generally increases. The electrons are closer to the nucleus and thus more strongly attracted to the center, making them more difficult to remove. So, the correct choices would be 'decreases going down within a group' and 'increases going across a period'.
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A hot "bubble" of air that breaks away from the warm surface and rises, expanding and cooling as it ascends, is known as a(n) _____. a. low pressure riser b. hot mass c. orographic uplift d. thermal
Answer: Thermal
Explanation: All areas on the earth surface does not absorb equal amount of sunlight, as a result of this, some areas tend to heat up more quickly than the others. The air in contact with these heated areas becomes warmer than its surroundings causing a hot bubble of air called ''thermal'' to break away from the warm surface,rising, expanding and cooling as it ascends, as observed during cloud development.
Final answer:
A rising hot "bubble" of air that expands and cools as it ascends due to convection is known as a thermal. This results in adiabatic cooling, which can lead to condensation and cloud formation.
Explanation:
A hot "bubble" of air that breaks away from the warm surface and rises, expanding and cooling as it ascends, is known as a thermal. This is due to the process of convection where warmer air, being less dense, rises above colder air. As this air rises, it expands due to lower atmospheric pressure at higher altitudes, which in turn causes it to cool, a process known as adiabatic cooling. If the air cools to its dew point, condensation can occur, potentially leading to cloud formation.
Air containing 0.04% carbon dioxide is pumped into a room whose volume is 6000 ft3. The air is pumped in at a rate of 2000 ft3/min, and the circulated air is then pumped out at the same rate. If there is an initial concentration of 0.2% carbon dioxide, determine the subsequent amount in the room at any time.
Here is the full question:
Air containing 0.04% carbon dioxide is pumped into a room whose volume is 6000 ft3. The air is pumped in at a rate of 2000 ft3/min, and the circulated air is then pumped out at the same rate. If there is an initial concentration of 0.2% carbon dioxide, determine the subsequent amount in the room at any time.
What is the concentration at 10 minutes? (Round your answer to three decimal places.
Answer:
0.046 %
Explanation:
The rate-in;
[tex]R_{in}[/tex] [tex]= \frac{0.04}{100}*2000[/tex]
[tex]R_{in}[/tex] = 0.8
The rate-out
[tex]R_{out}[/tex] = [tex]\frac{A}{6000}*2000[/tex]
[tex]R_{out}[/tex] = [tex]\frac{A}{3}[/tex]
We can say that:
[tex]\frac{dA}{dt}=[/tex] [tex]0.8-\frac{A}{3}[/tex]
where;
A(0)= 0.2% × 6000
A(0)= 0.002 × 6000
A(0)= 12
[tex]\frac{dA}{dt} +\frac{A}{3} =0.8[/tex]
Integration of the above linear equation =
[tex]e^{\int\limits \frac {1}{3}dt } =[/tex] [tex]e^{\frac{1}{3}t[/tex]
so we have:
[tex]e^{\frac{1}{3}t}\frac{dA}{dt}} +\frac{1}{3}e^{\frac{1}{3}t}A[/tex] [tex]= 0.8e^{\frac{1}{3}t[/tex]
[tex]\frac{d}{dt}[e^{\frac{1}{3}t}A][/tex] [tex]= 0.8e^{\frac{1}{3}t[/tex]
[tex]Ae^{\frac{1}{3}t} =2.4e\frac{1}{3}t +C[/tex]
∴ [tex]A(t) = 2.4 +Ce^{-\frac{1}{3}t[/tex]
Since A(0) = 12
Then;
[tex]12 =2.4 + Ce^{-\frac{1}{3}}(0)[/tex]
[tex]C= 12-2.4[/tex]
[tex]C =9.6[/tex]
Hence;
[tex]A(t) = 2.4 +9.6e^{-\frac{t}{3}}[/tex]
[tex]A(0) = 2.4 +9.6e^{-\frac{10}{3}}[/tex]
[tex]A(t) = 2.74[/tex]
∴ the concentration at 10 minutes is ;
= [tex]\frac{2.74}{6000}*100[/tex]%
= 0.0456667 %
= 0.046% to three decimal places
Which statement describes a change that occurs during a chemical reaction? A. Atoms in the original substances are arranged in a different way to make new substances. B. The atoms in a substance change their properties so they can become a new substance. C. The atoms in a substance start to move faster until they are no longer touching each other. D. Atoms in the original substances are changed into different atoms to make new substances.
Answer:
A
Explanation:
During a chemical reaction two or more chemical substances interact with one another, causing the atoms to move around and rearrange their arraignment and bond together in a different way to make a new product or products.
Answer:
A
Explanation:
One of the principal laws guiding chemical reactions is the law of conservation of mass. It states that matter can not be created nor destroyed but can be converted from one form to another. Although this has been shown to be wrong to an extent, it is still the basic law guiding the way in which chemical reactions operate.
Now, to form new substances, we have some old substances coming together. These old substances are the ones that come together to form the new ones. Surely, these old substances have their own atoms too. Since they are not destroyed in the process of forming new substances, what will happen is that they are rearranged or converted from their original form to another new form to make way for the emergence of new substance type.
What is the rate of the reaction if the concentrations of A and C are doubled and the concentration of B is tripled?
This is an incomplete question, here is a complete question.
Consider the following reaction:
[tex]A+B+C\rightarrow D[/tex]
The rate law for this reaction is as follows:
[tex]Rate=k\times \frac{[A][C]^2}{[B]^{1/2}}[/tex]
Suppose the rate of the reaction at certain initial concentrations of A, B, and C is 1.12 × 10⁻² M/s.
What is the rate of the reaction if the concentrations of A and C are doubled and the concentration of B is tripled?
Rate 2 = ? M/s
Answer : The rate of reaction will be, [tex]5.17\times 10^{-2}M/s[/tex]
Explanation :
Rate law : It is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.
The given chemical reaction is,
[tex]A+B+C\rightarrow D[/tex]
The expression of rate law for this reaction will be,
[tex]\text{ Initial rate}=k\times \frac{[A][C]^2}{[B]^{1/2}}[/tex]
As the concentrations of A and C are doubled and the concentration of B is tripled then the rate of reaction will be:
[tex]Rate=k\times \frac{[2A][2C]^2}{[3B]^1/2}[/tex]
[tex]Rate=4.62k\times \frac{[A][C]^2}{[B]^{1/2}}[/tex]
[tex]Rate=4.62\times \text{ Initial rate}[/tex]
Given:
Initial rate = 1.12 × 10⁻² M/s
[tex]Rate=4.62\times 1.12\times 10^{-2}M/s[/tex]
[tex]Rate=5.17\times 10^{-2}M/s[/tex]
Thus, the rate of reaction will be, [tex]5.17\times 10^{-2}M/s[/tex]
Chlorine gas can be prepared in the laboratory by the reaction of hydrochloric acid with manganese(IV) oxide:
4HCL(aq) + MnO2(s) ----> MnCl2(aq) + 2H2O(l) + Cl2(g)
You add 42.5 g of MnO2 to a solution containing 47.7 g of HCl.
(a) What is the limiting reactant? MnO2 or HCL?
(b) What is the theortical yield of CO2?
(c) If the yield of the reaction is 79.9%, what is the actual yield of chlorine?
Answer:
a) HCl
b) 22.9g
c) 18.11g
Explanation:
MMn = 54.94g/mol
MO2 = 2(16) = 32g/mol
MH = 1g/mol
MCl = 35.45g/mol
Molar Mass of MnO2:
54.94 + 2(16)= 86.94
Molar Mass of HCl:
1+35.45=36.45
Mols of MnO2:
42.7 /86.94 = 0.49
Mols of HCl:
47.1 /36.45 = 1.29
Molar Mass of Cl2:
35.45 ×2 = 70.9
Mols of Cl2
1.29/4=0.323
Mass of Cl2 (Theoretical yield)
0.323 ×70.9= 22.9
To calculate the actual yield, we multiply the theoretical yield by the final percentage:
22.9 ×0.791=18.11
The most abundant elements in the universe are hydrogen and helium, but there are also small but significant amounts of heavier elements in stars and planets and in our own bodies. Where did these heavy elements originate?
Answer:
in nuclear fusion deep in the interiors of stars
Explanation:
Nuclear fusion -
It is the type of reaction , where two or more atomic nuclei of the atom merges together to release two or more different nuclei along with some subatomic particles , is referred to as a nuclear fusion reaction .
The reaction can very well be done on stars , because of very high energy .
Hence , a nuclear fusion occurs deep inside the stars .
Write a statement that reads a floating point (real) value from standard input into temperature. Assume that temperature. has already been declared as an double variable.
Answer:
temperature = stdin.nextDouble();
Explanation: since the temperature has already been declared as a double variable, the above statement will read so.
As temperature equal standard input dot next double variable.
To read a floating point value from standard input into a double variable, use the scanf function with %lf format specifier.
Explanation:To read a floating point (real) value from standard input into a double variable named temperature, you can use the scanf function in the C programming language. The scanf function allows you to read formatted input, and the %lf format specifier is used to read a double value. Here's an example:
scanf("%lf", &temperature);This line of code will read a floating point value from the standard input and store it in the temperature variable declared as a double.
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Please Answer! Help! Will Give Brainliest. Find Keq for a 3.0 L container with 1.2 moles of both NO2 and N2O4 initially and 0.38 M NO2 at equilibrium. 2NO2(g) ⇌ N2O4(g)
Answer:
Kc → 41.9
Explanation:
This is the equilibrium:
2NO₂(g) ⇌ N₂O₄(g)
So the expression for Kc will be:
Kc = [N₂O₄] / [NO₂]²
We prospose the situations:
Initially we have 1.2 moles of NO₂ and N₂O₄
X amount has reacted. As stoichiometry is 2:1, we have produced x/2 of the product during the reaction
Finally In equilibrium we have, 0.38 NO₂
2NO₂(g) ⇌ N₂O₄(g)
Initially 1.2 1.2
React x x/2
Eq (1.2 - x) = 0.38 1.2 + x/2
As we have [NO₂] in the equilibrium, we can determine x (the amount that has reacted) to solve and determine, the [N₂O₄] in the equilibrium
1.2-0.38 = x → 0.82
1.2 + 0.82/2 = 2.02 → [N₂O₄]
For Kc, we need Molar concentration, so we have to divide [N₂O₄] and [NO₂] by the volume
[N₂O₄] → 2.02 mol/3L = 0.673 M
[NO₂] → 0.38 mol/3L = 0.127 M
Now we can replace the Kc expression:
Kc → [N₂O₄] / [NO₂]² → 0.673 / 0.127² = 41.9
Remember that Kc has no UNITS