Answer:
ΔHacetone = - 247.5 kJ/mol
Explanation:
The enthalpy equation is as follows
ΣnΔHproducts – ΣmΔHreactants =ΔHreaction
3×ΣnΔH(CO2(g)) + 3×ΣnΔH(H2O) - ΣnΔH (C3H6O(l)) =ΔHreaction = -1790 kJ/mol
[3(-393.5) + 3(-285.8)] – ΔHacetone
= -1790 kJ/mol
(-1180.5 – 857.4)kJ/mol - ΔHacetone =
-1790 kJ/mol
-2037.9 kJ/mol - ΔHacetone
= -1790kJ/mol
-2037.9 kJ/mol + 1790kJ/mol = ΔHacetone
- 247.5 kJ/mol = ΔHacetone
ΔHacetone = - 247.5 kJ/mol
To determine the standard enthalpy of formation of acetone (C3H6O), we can use the combustion reaction equation and the standard enthalpies of formation of other compounds involved. By applying Hess's Law and the enthalpy change of the reaction, we can calculate the standard enthalpy of formation.
Explanation:The standard enthalpy of formation of acetone (C3H6O) can be calculated using the given equation for the combustion of acetone and the standard enthalpies of formation of O2(g), CO2(g), and H2O(l). For the combustion reaction:
C3H6O(l) + 4O2(g) → 3CO2(g) + 3H2O(l)
The enthalpy change or ΔH of the reaction is -1790 kJ. Using Hess's Law and the enthalpy change, we can determine the standard enthalpy of formation of acetone.
We can set up an equation using the standard enthalpy of formation values:
ΔH = Σ(ΔHf(products)) - Σ(ΔHf(reactants))
By rearranging the equation, we can solve for the standard enthalpy of formation of acetone.
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Why are the Nobel Gases so unreactive?
A.) Because they are used for cancer treatment.
B.) They have a full valence shell (outer electrons) of 8.
C.) Because they have a high boiling point.
Answer:B
Explanation:
They have a full valence shell of 8
. A solution is prepared by dissolving 23.7 g of CaCl2 in 375 g of water. The density of the resulting solution is 1.05 g/mL. The concentration of CaCl2 in this solution is __________ molar.
a. 0.564
b. 0.571
c. 0.569
d. 0.537
e. 0.214
Answer:
The concentration of CaCl2 in this solution is 0.564 molar (option A)
Explanation:
Step 1: Data given
Mass of CaCl2 = 23.7 grams
Mass of water = 375 grams
Density of solution is 1.05 g/mL
Step 2: Calculate total mass
Total mass = mass of CaCl2 + mass of water
Total mass = 23.7 grams + 375 grams = 398.7 grams
Step 3: Calculate volume of the solution
Density = mass / volume
Volume = mass / density
Volume = 398.7 grams / 1.05 g/mL
Volume = 379.7 mL = 0.3797 L
Step 4: Calculate moles CaCl2
Moles CaCl2 = mass CaCl2 / molar mass CaCl2
Moles CaCl2 = 23.7 grams / 110.98 g/mol
Moles CaCl2 = 0.214 moles
Step 5: Calculate concentration
Concentration of CaCl2 = moles / volume
Concentration of CaCl2 = 0.214 moles / 0.3797 L
Concentration of CaCl2 = 0.564 mol / L = 0.564 molar
The concentration of CaCl2 in this solution is 0.564 molar (option A)
You have a 1.153 g sample of an unknown solid acid, HA, dissolved in enough water to make 20.00 mL of solution. HA reacts with KOH(aq) according to the following balanced chemical equation:?
Answer:
HA + KOH → KA + H₂O
Explanation:
The unknown solid acid in water can release its proton as this:
HA + H₂O → H₃O⁺ + A⁻
As we have the anion A⁻, when it bonded to the cation K⁺, salt can be generated, so the reaction of HA and KOH must be a neutralization one, where you form water and a salt
HA + KOH → KA + H₂O
It is a neutralization reaction because H⁺ from the acid and OH⁻ from the base can be neutralized as water
Describe the two known major natural mechanisms for converting atmospheric nitrogen to useable forms.
Answer:
(a). Biological fixation
(b). Fixation by lightning
Explanation:
Gaseous nitrogen in the atmosphere has to be converted or "fixed" into a suitable form before it can be utilised by living organisms.
There two main ways of nitrogen fixation are
(a). Biological fixation: Majority (approximately 90%) of nitrogen fixation is carried out by bacteria. Bacterias such as Cyanobacteria transforms nitrogen into ammonium and ammonia : N2 + 3 H2 → 2 NH3. The produced ammonia can then be taken in directly by plants and /or the conversion products of ammonium and ammonia may further react in the process of nitrification.
(b). Fixation by lightning: Lightning energy causes the combination nitrogen (N2) and water (H2O) forming nitrates (NO3) and ammonia (NH3) . Rain water dissolves the formed nitrates and ammonia and the solution is drained into the ground, where they can be reached by plants plant roots for consumption.
Biological nitrogen fixation and lightning are the major natural processes responsible for converting atmospheric nitrogen to useable forms.
What processes responsible for converting atmospheric nitrogen to useable forms?Nitrogen gas goes into the soil from the atmosphere, and nitrogen fixing bacteria convert this nitrogen to ammonium ions (NH4+), which can be used by plants.
Whereas, Lightning converts atmospheric nitrogen into ammonia and nitrate (NO3) that comes to the soil with the help of rainfall.
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Consider just the first sentence of this multistep word problem. Sentence 1: The sum of the ages of a brother and sister is 26. Give an equation that represents this statement using b as the age of the brother and s as the age of the sister. Express your answer in terms of the symbols b and s.
Answer:
a. b + s = 26
b. b = 26 — s
Explanation:
Annie has a soccer ball and a kickball she kicks each ball with the same force the soccer ball accelerates at 3 m/s to the second power and the kickball accelerates at 5 m/s to the second power Use Newtons laws to describe why the kickball has a greater acceleration
Answer:
Because of less weight kick ball has more acceleration.
Explanation:
Acceleration of kick ball:
5 m/s
Acceleration of soccer ball:
3 m/s
Newton's second law:
According to newton's second law the acceleration of object depends upon two variables.
1) Mass of object
2) Force acting on it
Mathematical expression:
a = f/m
a = acceleration
f = force
m = mass
The force on balls are same thus the acceleration is depend upon the masses of balls.
The soccer ball has more weight that's why its acceleration is less while kick ball is lighter and thus its acceleration will more.
Answer:
Based on Newton's second law, if the balls are kicked with the same force, the one with less mass will have a greater acceleration. Since the kickball accelerates more than the soccer ball, it has less mass.
Explanation:
An aqueous solution is 3.00% by mass dextrose (C6H12O6) in water. If the density of the solution is 1.0097 g/mL, calculate the molarity of dextrose in the solution.
Answer:
[C₆H₁₂O₆] = 0.17M
Explanation:
3% by mass, means 3 g of solute in 100 g of solution.
Density is mass / volume. This data always refers to solution.
Solution density = Solution mass / Solution volume
1.0097 g/mL = 100 g / Solution volume
Solution volume = 100 g / 1.0097 g/mL → 99.03 mL
Let's convert the mL to L, for molarity (mol/L)
99.03 mL = 0.09903 L
Now we have to find out the moles. Let's calculate them with the molar mass
(mass / molar mass)
3 g / 180 g/mol = 0.0166 mol
Molarity is mol/L → 0.0166 mol/0.09903 L → 0.17 M
The molarity of dextrose in a 3.00% by mass aqueous solution, with a density of 1.0097 g/mL, is calculated to be approximately 0.168 M by dividing the number of moles of dextrose (0.01665 mol) by the volume of the solution in liters (0.09903 L).
Explanation:To calculate the molarity of dextrose in the solution, we'll first need to understand that molarity is defined as the number of moles of solute per liter of solution. Here, the solution is 3.00% by mass dextrose. This means that in 100 grams of the solution, there are 3 grams of dextrose.
Using the density of the solution (1.0097 g/mL), we'll calculate the volume that 100 grams of the solution occupies:
Volume = mass / density = 100 g / 1.0097 g/mL = 99.03 mL100 grams of solution contains 3 grams of dextrose. With the molar mass of dextrose (C6H12O6) being 180.16 g/mol, we calculate the number of moles in those 3 grams:
Moles of dextrose = mass of dextrose / molar mass = 3 g / 180.16 g/mol = 0.01665 molTo find the molarity, we need the volume in liters:
Volume in liters = 99.03 mL / 1000 = 0.09903 LThus, the molarity (M) is:
M = moles of solute / volume in liters = 0.01665 mol / 0.09903 L ≈ 0.168 MThe molarity of dextrose in the solution is approximately 0.168 M.
What is the type of strong chemical bond between carbon, hydrogen, and oxygen atoms in a single organic molecule?
Answer:
covalent bond
Explanation:
Covalent bond -
It is the type of interaction observed between two species , which share the electrons in order to attain stability , is referred to as covalent bond.
The shared electrons are referred to as the bonding pairs or the shared pairs .
Stability and completion of the octet is the driving force for the formation covalent bond.
The molecules of the organic compound usually shows this type bonding .
Like the bonds between - carbon , oxygen and hydrogen are covalent bonds.
Choose the aqueous solution below with the lowest freezing point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable. Choose the aqueous solution below with the lowest freezing point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.
A. 0.075 m Li I
B. 0.075 m (NH4)3PO4
C. 0.075 m NaIO4
D. 0.075 m KCN
E. 0.075 m KNO2
Answer:
B. 0.075 m (NH4)3PO4
Explanation:
Our strategy here is to recall the van´t Hoff factor, i, for the colligative properties of electrolyte solutions which appears as the consequence that electrolytes disociate completely in their solutions in water.
Thus in this problem we need to determine i and then realize the one with the lowest freezing point will have the biggest i ( all the concentrations are equal) since
ΔTf = i m Kf
Substance van´t Hoff factor
Li I 2
(NH4)3PO4 4
NaIO4 2
KCN 2
KNO2 2
The correct answer is B. 0.075 m (NH4)3PO4
The aqueous solution with the lowest freezing point is 0.075 m (NH4)3PO4 because it dissociates into the highest number of particles, leading to the greatest freezing point depression.
Explanation:To find the aqueous solution with the lowest freezing point, we need to determine the effective concentration of solute particles after dissociation. Freezing point depression is larger for solutions with a higher number of dissolved particles. Therefore, we must consider the van't Hoff factor (i), which is the number of particles a compound dissociates into in solution. For example, LiI (i=2), NaIO4 (i=1), and KCN (i=2) will produce fewer particles than (NH4)3PO4, which will dissociate into four particles (i=4).
Given that the molal concentrations (m) are the same, the solution with the highest van't Hoff factor will have the highest concentration of particles and therefore, the lowest freezing point. Hence, solution B, 0.075 m (NH4)3PO4, with an effective concentration of 0.3 m (0.075 m × 4), will have the lowest freezing point.
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How many moles of water are made from complete reaction of 1.4 moles of hydrogen gas? Given the reaction: 2H2 + O2 → 2H2O
Answer:
1.4moles
Explanation:
From the balanced equation below;
2H2 + O2 → 2H2O
2moles of hydrogen reacts with 1mole of oxygen to produce 2moles of water.
since we are only interested in comparing hydrogen and water, we can say 2moles of hydrogen will produce 2moles of water
Hence by comparism of moles;
1.4moles of hydrogen will produce 1.4moles of water
In the reaction 2H2 + O2 → 2H2O, the formation of water from hydrogen gas is a 1:1 ratio. Thus, 1.4 moles of hydrogen gas would produce 1.4 moles of water.
Explanation:Analyzing balanced chemical equations is a fundamental approach to determine the stoichiometry of a chemical reaction. In this case, the equation 2H2 + O2 → 2H2O provides crucial information regarding the mole ratios of reactants and products. It signifies that 2 moles of hydrogen gas (H2) react completely with 1 mole of oxygen gas (O2) to yield 2 moles of water (H2O).
Therefore, when 1.4 moles of hydrogen gas are fully consumed in the reaction, the stoichiometry reveals that an equivalent amount, 1.4 moles, of water will be generated. This clear and direct correlation underscores the predictive power of balanced chemical equations in understanding the quantities of reactants and products in a chemical reaction.
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I have this question for homework. But balancing chemical equations has never been my strong point can somebody explain it to me please?
3. When propane burns in air, it reacts with
oxygen (O2) to form carbon dioxide (CO)
and water (H2O). Which balanced chemical
equation describes this reaction?
A. C3Hg + O2 + CO2 + H2O
B. C3H8 + 402 CO2 + 4H2O
C. C3H3 + 502 3C02 + H2O
D. C3Hg + 502 → 3CO2 + 4H2O
Answer:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
Option D.
Explanation:
This is a combustion reaction, where a compound reacts with oxygen to produce CO₂ and water.
You have to look at the reactants and the products.
C₃H₈ + O₂ → CO₂ + H₂O
To balance you must have the same atoms of each elements in both sides.
Actually we have 3 C, 8 H and 2 O in reactant side and 1 C, 3 O and 2H in product side.
We can add 4 to water to have 8 H in product side to balance the H with reactants but we modified the amount of oxygens. Now, we have 4 O in water and 2 O from CO₂ (6 in total).
In reactant side, we have 3 C, therefore we add 3 to CO₂ and now, we have 3 C on both sides and 8 H in both sides, so, as in product side we have 10 O, 6 from CO₂ and 4 from water, we must add a 5 to balance in reactant side. The balance equation will be:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
If an evaluating committee places the burden of proof of the safety of a new chemical on the manufacturer of the chemical, then the committee is using the _________.
If an evaluating committee places the burden of proof of the safety of a new chemical on the manufacturer of the chemical, then the committee is using the precautionary principle
Explanation:
This is a method that is used to handle the problems that are related in affecting any person. This principle mainly aims in determining the safety of any new thing before it is released to the public. This will test whether the new thing does not make harm or destroy anything before it is introduced to public.
For instance let us take an example of a medicine introduction. Any new tablets when it is discovered must be tested. Without any testing, releasing it to public will only have adverse effect on them. The given scenario also relates with the precautionary principle since, the safety is considered as an important one by the evaluating committee.
A coffee cup calorimeter initially contains 125g of water at 24.2oC. 10.5g of potassium bromide also at 24.2oC is added to the water. After the KBr dissolves the final temperature is 21.1oC. Calculate the enthalpy change for dissolving the salt in J/g and kJ/mol. Assume specific heat of solution is 4.18J/goC.
To calculate the enthalpy change for dissolving potassium bromide, use the equation q = mcΔT. Then divide the heat gained or lost by the mass of the substance to get the enthalpy change in J/g. To convert to kJ/mol, divide by the molar mass of potassium bromide.
Explanation:To calculate the enthalpy change for dissolving the salt, we need to use the equation q = mcΔT, where q is the heat, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. First, we calculate the heat gained by the water using m = 125g, c = 4.18J/goC, and ΔT = 24.2oC - 21.1oC. Next, we calculate the heat lost by the potassium bromide using m = 10.5g, c = 4.18J/goC, and ΔT = 24.2oC - 21.1oC. Finally, we can calculate the enthalpy change in J/g by dividing the heat gained or lost by the mass of the substance. To convert to kJ/mol, we need to use the molar mass of potassium bromide and divide the enthalpy change in J/g by the molar mass.
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You have a total body concentration of 300 mOsM and total body volume of 3 liters. If you add 0.5 L of a solution containing 150 mosmol of NaCl to the body, what would the new total body concentration be?
Answer:
The new total body concentration would be 300 mOsM
Explanation:
In order to do this, we need to convert all concentrations to moles.
First, with the total body concentration, we have the initial volume of 3 liters and the concentration of 300 M (I will omit til the end the part of mOs)
The moles of the body concentration in this volume is:
moles = M * V
moles = 300 * 3 = 900 moles
To this moles, we add 150 moles of NaCL so, the total moles now is:
moles = 900 + 150 = 1050 moles
Finally, we can calculate the concentration with the new volume of 3.5 L (the sum of 3 and 0.5 liters added):
M = 1050 / 3.5
M = 300 mOsM
So the concentration remains the same as initial
As the temperature of a gas sample increases, the number of molecules and volume remaining constant, the pressure exerted by the gasA. increasesB. decreasesC. stays the same
Answer:
A. increases
Explanation:
According to the Gay-Lussac's law:-
Thus, at constant volume and number of moles, Pressure of the gas is directly proportional to the temperature of the gas.
P ∝ T
Also, it can be written as:-
[tex]\frac {P_1}{T_1}=\frac {P_2}{T_2}[/tex]
Thus, if the temperature is increased, the pressure exerted by the gas also increases.
You happen to be visiting Northem California and you are driving by Suisun Bay, a notorious graveyard for old ships You notice that all of these ships appear to be nusting may Which of the following statements is true?
a. The rusting of the metal is neither a chemical change nor a physical change
b. The rusting of the metal is a chemical change
c. The rusting of the metal is both a chemical change and a physical change
d. The rusting of the metal is a physical change
Answer: B. Rusting of the metal is a chemical change.
Explanation: Rusting is considered a chemical change since it involves a change in the composition of iron through oxidation. Since there is a presence of oxygen and moisture it weakens the bonds of iron molecules to react and form iron oxide another substance in the chemical process.
The R group or side chain of the amino acid leucine is non-polar. The R group of serine is polar. Where would you expect to find these amino acids in a globular protein in aqueous solution?
Answer:
Serine will be on the exterior of the globular protein while leucine on the interior of the globular proteins
Explanation:
The nature or solubility of the side cham determines the poition of amino acid on the globular protein and it is either hydrophilic or hydrophobic.
Serine is an hydrophilic amino acid and so it is position on the surface of the globular protein (Exterior)
While Leucine side chain is hydrophobic in nature is positioned on the interior of the globular protein.
Leucine, a non-polar amino acid, tends to be in the interior of globular proteins while serine, a polar amino acid, is often found on the surface.
Explanation:In an aqueous environment of globular proteins, the position of an amino acid is influenced by the polar or non-polar nature of its R group or side chain. Leucine, with a non-polar R group, prefers to stay in the interior part of the protein, away from the water, because non-polar R groups are hydrophobic. On the other hand, serine, with a polar R group, tends to stay on the surface, close to the water, due to its hydrophilic or water-attracting nature.
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Use Dalton’s atomic theory to explain what is happening to the carbon atoms when a diamond is burned and to oxygen and hydrogen atoms when water is electrolyzed.
Answer:
Diamond is burnt
Diamond (Carbon)+ Oxygen → CO2
Water electrolysed
2H2O → 2H2 + O2
Explanation:
Dalton atomic theory states that in a chemical reaction, the atoms of the elements join together or combine in simple whole number ratios
Hence when, at very high temperatures, diamond which consists of carbon is burnt we have
Diamond (Carbon)+ Oxygen → CO2
Also when water is electrolysed it decomposes as follows
2H2O → 2H2 + O2
If an enclosure of 0.432 L has a partial pressure of O2 of 3.4×10−6 torr at 28 ∘C, what mass of magnesium will react according to the following equation? 2Mg(s)+O2(g)→2MgO(s)
The mass of the magnesium that is produced is [tex]2.1 * 10^{-8[/tex] g.
What is ideal gas equation?The ideal gas equation can also be expressed in different forms to solve for different parameters. For example, it can be rearranged to find the molar volume (V/n) or the number of moles (n) when other variables are known.
We have that;
PV = nRT
n = PV/RT
n = [tex]3.4 * 10^{-6[/tex] * 0.432/62.4 * 55
n = [tex]4.3 * 10^{-10[/tex] moles
If 2 moles of Mg produces 1 mole of oxygen
x moles of oxygen produces [tex]4.3 * 10^{-10[/tex] moles of oxygen
x =[tex]8.6 * 10^{-10[/tex] moles
Mass of magnesium = [tex]8.6 * 10^{-10[/tex] moles * 24 g/mol
= [tex]2.1 * 10^{-8[/tex] g
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Part IV. For each trial, calculate the number moles of 6.0 M HCl used in the reaction. Report your answer using 4 digits. Note that it is 1 or 2 digits beyond the number of significant figures, i.e. 0.2345 moles.
This is an incomplete question, here is a complete question.
For each trial, calculate the number moles of 6.0 M HCl used in the reaction?
Trial 1 : Volume of HCl = 15.0ml
Trial 2 : Volume of HCl = 14.9ml
Trial 3 : Volume of HCl = 15.2ml
Answer :
The number moles of HCl for trial 1, 2 and 3 is, 0.090 mol, 0.089 mol and 0.091 mol
Explanation :
Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.
Formula used :
[tex]\text{Molarity}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}[/tex]
In this question, the solute is HCl.
Now we have to calculate the number of moles of HCl for trial 1.
Volume of HCl = 15.0 mL = 0.015 L
[tex]6.0M=\frac{\text{Moles of HCl}}{0.015L}[/tex]
[tex]\text{Moles of HCl}=0.090mol[/tex]
Now we have to calculate the number of moles of HCl for trial 2.
Volume of HCl = 14.9 mL = 0.0149 L
[tex]6.0M=\frac{\text{Moles of HCl}}{0.0149L}[/tex]
[tex]\text{Moles of HCl}=0.089mol[/tex]
Now we have to calculate the number of moles of HCl for trial 3.
Volume of HCl = 15.2 mL = 0.0152 L
[tex]6.0M=\frac{\text{Moles of HCl}}{0.0152L}[/tex]
[tex]\text{Moles of HCl}=0.091mol[/tex]
If the absolute temperature of a gas is 600 K, the temperature in degrees Celsius is A. 705°C. B. 327°C. C. 273°C. D. 873°C.
Answer:
Option B. 327°C
Explanation:
Absolute T° = T° in K
T° in K = T° in C + 273
T° in K - 273 = T° in C
600 K - 273 = 327°C
Which type of interaction does NOT contribute to the stabilization of the tertiary structure of a protein? a.Disulfide bond b.Phosphodiester bond c.Hydrogen bond d.Salt bridge
Answer:
Option b, Phosphodiester bond
Explanation:
Proteins are sequence of amino acids. Two amino acids are joined by peptide bond. Therefore, proteins are also known as sequence of polypeptide chains. These polypeptides chains have four level of structures:
Primary structure
secondary structure
Tertiary structure
Quaternary structure
Primary structure is simply a sequence of amino acids. In secondary, tertiary and Quaternary structure, various interactions are present.
Disulfide bond, hydrogen bond and salt bridge stabilizes tertiary structure of the protein.
Phosphodiester bond is present as link between two nucleotides and thus, present in the backbone of nucleic acid (RNA and DNA)
Therefore, the correct option is option b
Among disulfide bonds, hydrogen bonds, salt bridges, and phosphodiester bonds, the latter does not contribute to the stabilization of the tertiary structure of a protein. Instead, phosphodiester bonds are crucial in the formation of nucleic acids.
Explanation:In regards to protein structure, the interaction types that contribute to the stabilization of the tertiary structure of a protein include disulfide bonds, hydrogen bonds, and salt bridges.
Disulfide bonds are covalent bonds between two sulfur atoms that stabilize the protein structure. Hydrogen bonds are weak forces of attraction between the hydrogen atom in one molecule and an electronegative atom in another. Salt bridges are ionic bonds between amino acid side chains that also stabilize the protein structure.
However, the phosphodiester bond does not play a role in tertiary protein structure. This type of bond is important in the formation of nucleic acids, such as DNA and RNA, where it links the 3' carbon of one nucleotide to the 5' carbon of another. It serves a different purpose in molecular biology and does not contribute to the stabilization of the tertiary structure of a protein.
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You have 10.0 g each of Na, C, Pb, Cu and Ne. Which contains the smallest number of moles? You have 10.0 g each of Na, C, Pb, Cu and Ne. Which contains the smallest number of moles?
1. Pb
2. Cu
3. Ne
4. Na
Answer:
The answer to your question is number 1. Pb
Explanation:
Data
10 grams of Na, C, Pb, and Ne
Process
Calculate the moles of each element
23 g of Na ----------------- 1 mol
10 g of Na ------------------- x
x = 0.43 moles of Na
20 g of Ne ---------------- 1 mol
10 g of Ne ----------------- x
x = 0.5 moles of Ne
64 g of Cu -------------- 1 mol
10 g of Cu -------------- x
x = 0.16 moles of Cu
207 g of Pb ------------- 1 mol
10 g of Pb -------------- x
x = 0.048 moles of Pb
Pb has the smallest number of moles
Answer:
Pb contains the smallest no of moles
Mole = mass/atomic mass
For lead no of mole = 10g/207.2g/mol
= 0.04826mol
For Cu no of mole = 10g/63.546g/mol = 0.1574mol
For Ne no of mole = 10g/20.1797g/mol = 0.4955mol
For Na no of mole = 10g/22.9898g/mol = 0.5350mol
You are studying the equilibirum between S8 and S2 gases at 0 celcius, you place a smaple of s2 in an otherwise empty, rigid container at an initial pressure of 3.-0 atm. wher eit reactsto form S8. at equilimrium, the partial pressure of s2 is 2.07 atm. calculate kp and kc.
Answer:
Kp and Kc are 0.01266 and 145.17, respectively.
Explanation:
Please check document attached.
Solid lithium hydride reacts with water to form aqueous lithium hydroxide and hydrogen gas. When this equation is written and balanced, the coefficient of lithium hydride is?
Answer:
The coefficient of LiH is 1 (non written)
Explanation:
The equation is this:
LiH (s) + H₂O (l) → LiOH (aq) + H₂ (g)
Ratio is 1:1 between reactants and products.
The coefficient of LiH is 1
Li2O(s)+H2O(l)→2LiOH(aq)
For the endothermic formation of sulfuric acid H2O(g) + SO3(g) ↔ H2SO4(g) _______ the pressure of the system and ________ the temperature of the system would shift the reaction to the left.
1. decreasing, lowering
2. decreasing, raising
3. increasing, raising
4. increasing, lowering
Answer: Option (1) is the correct answer.
Explanation:
As per Le Chatelier's principle, any disturbance caused in an equilibrium reaction will tend to shift the equilibrium in a direction away from the disturbance.
For example, [tex]H_{2}O(g) + SO_{3}(g) \rightleftarrow H_{2}SO_{4}(g)[/tex]
As this given reaction is endothermic in the forward direction and exothermic in the backward direction. Thus, in order to shift the reaction on left side we need to decrease the temperature.
Also, the number of moles are more on reactant side as compared to product side. So, when we decrease the number of moles on reactant side then the equilibrium will shift on left side.
Therefore, we can conclude that for the given reaction decreasing the pressure of the system and lowering the temperature of the system would shift the reaction to the left.
Final answer:
Decreasing the pressure of the system and lowering the temperature for the reaction H₂O(g) + SO₃(g) ⇔ H₂SO₄(g) both shift the equilibrium to the left because Le Chatelier's Principle dictates that the system will counteract changes by shifting towards more gas molecules (when pressure decreases) and by absorbing heat (when temperature is lowered for an endothermic reaction).
Explanation:
To determine how changes in pressure and temperature affect the equilibrium of the reaction H₂O(g) + SO₃(g) ⇒H₂SO₄(g), Le Chatelier's Principle can be applied. This principle states that if a system at equilibrium is subjected to a change in conditions, the system will adjust to partially counteract the effect of the change.
For the reaction given, if we decrease the pressure, the equilibrium will shift towards the side with more gas molecules to increase the pressure again. Since the left side has two moles of gas and the right side has only one, decreasing the pressure will shift the equilibrium to the left.
Regarding temperature, since it's an endothermic reaction, heat can be considered a reactant. So, if we lower the temperature, the system will shift towards the side that absorbs heat to counteract the decrease in temperature, which would be shifting the equilibrium to the left. Therefore, the correct answer is 1. decreasing, lowering.
Measurements show that the ph of a particular lake is 4.0. What is the hydroxide ion concentration of the lake?
Answer:
[OH⁻] → 1×10⁻¹⁰
Explanation:
pH = - log [H⁺]
pOH = - log [OH⁻]
pH + pOH = 14
4 + pOH = 14
14 - 4 = 10 → pOH
10^-pOH = [OH⁻]
10⁻¹⁰ = [OH⁻] → 1×10⁻¹⁰
The pOH of the lake is 10 (calculated by subtracting the pH from 14), and the hydroxide ion concentration of the lake is 10^(-10) moles per liter, obtained by raising 10 to the power of the negative pOH.
Explanation:The pH of a solution is a measure of the hydrogen ion concentration, and the pOH is a measure of the hydroxide ion concentration. In water, pH and pOH are related to each other, and have a sum of 14 at room temperature. When the pH of the solution is given, you can find the pOH by subtracting the pH from 14. In this case, the pH of the lake is 4.0, so the pOH would be 14 - 4 = 10. The concentration of hydroxide ions in a solution can be calculated using the formula 10^(-pOH). So, the hydroxide ion concentration of the lake is 10^(-10) moles per liter.
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In the equation 2 H2 + O2 -> 2H2O, H2, O2, and H2O are all trace elements. Only H2O is a compound. Only H2 and O2 are compounds. H2, O2, and H2O are ALL elements. H2, O2, and H2O are ALL compounds.
Answer: only H2O is a compound
Explanation:
A mixture of N2, O2 and He have mole fractions of 0.25, 0.65, and 0.10, respectively. What is the pressure of N2 if the total pressure of the mixture is 3.9 atm?
Answer:
Partia pressure N₂ → 0.975 atm
Explanation:
Let's analyse the moles fractions:
N₂ → 0.25
O₂ → 0.65
He → 0.1
Partial pressure / Total pressure = Mole fraction
Partial pressure N₂ / 3.9 atm = Mole fraction N₂
Partial pressure N₂ / 3.9 atm = 0.25
Partial pressure N₂ = 3.9 atm . 0.25 → 0.975 atm
The pressure of nitrogen in the mixture has been 0.975 atm.
Partial pressure has been defined as the pressure exerted by the gas molecules in the mixture. The partial pressure ([tex]P_A[/tex]) has been expressed as:
[tex]P_A=X_A\;\times\;P[/tex]
Where, Mole fraction of the element A, [tex]X_{N_2}=0.25\;\rm atm[/tex]
The total pressure of the mixture, [tex]P=3.9\;\rm atm[/tex]
Substituting the values, the pressure of nitrogen ([tex]P_{\rm N_2}[/tex]),
[tex]P_{\rm N_2}=0.25\;\times\;3.9\;\rm atm\\ \textit P_{N_2}=0.975\;atm[/tex]
The pressure of nitrogen in the mixture has been 0.975 atm.
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Assuming all volume measurements are made at the same temperature and pressure, what volume of hydrogen gas is needed to react completely with 4.55 L of oxygen gas to produce water vapor?
Answer:
9.1L
Explanation:
Firstly, to solve the problem, we need a balanced chemical equation.
2H2 + O2 ———> 2H2O
2 moles of hydrogen reacted one mole of oxygen. Now, we know that at STP, one mole of a gas occupies a volume of 22.4L, now let us get the number of moles in 4.55L of oxygen.
This means 4.55/22.4 = 0.203125 mole
Since in theory we have 2 moles of hydrogen reacting one mole of oxygen. Hence the number of moles of hydrogen we have is 0.203125 * 2 = 0.40625 mole
We now proceed to get the volume of hydrogen gas. Since 1 mole is 22.4L, then
0.40625 Is 0.40625 * 22.4 = 9.1L
To react with 4.55 L of oxygen gas completely, you need 9.10 L of hydrogen gas. This follows the balanced chemical equation 2H₂ + O₂ → 2H₂O, which indicates a 2:1 ratio between hydrogen and oxygen volumes.
To determine the volume of hydrogen gas needed to react completely with 4.55 L of oxygen gas to produce water vapor, we begin with the balanced chemical equation:
2H₂(g) + O₂(g) → 2H₂O(g)
This tells us that 2 volumes of hydrogen gas react with 1 volume of oxygen gas. Therefore, to find the necessary volume of hydrogen gas:
Recognize the stoichiometric ratio from the equation: 2 volumes of hydrogen gas (H₂) react with 1 volume of oxygen gas (O₂).
Given that there are 4.55 L of oxygen gas, apply the ratio:
Volume of H₂ needed = 2 times the volume of O₂ = 2 x 4.55 L = 9.10 L
Thus, 9.10 L of hydrogen gas is required to react completely with 4.55 L of oxygen gas under the same conditions of temperature and pressure.