Final answer:
To calculate the percent by mass of each element in a compound, divide the mass of each element in one mole by the total molar mass of the compound and multiply by 100. The sum of the percentages for all elements should equal 100% for a pure compound.
Explanation:
To determine the percent by mass of each element in a compound, one needs to carry out a series of calculations. First, you should find the mass of each element in one mole of the compound by using the compound's chemical formula and the atomic masses of the elements (this can be found on the periodic table). Then, divide this mass by the compound's molar mass (which is the sum of all the atomic masses from the chemical formula) and multiply the result by 100 to get the percentage. The sum of these percentages for all elements in the compound should be 100%, assuming the compound is pure.
True.
The percent by mass of an element in a compound can be calculated by dividing the molar mass of that element by the total molar mass of the compound and then multiplying by 100 to express it as a percentage. This calculation gives the proportion of the compound's mass that is attributed to a specific element.
True. To find the percent by mass of an element in a compound, you can use the formula:
[tex]\[ \text{Percent by Mass} = \left( \frac{\text{Molar Mass of Element}}{\text{Total Molar Mass of Compound}} \right) \times 100 \][/tex]
Here's how it works: For each element in the compound, calculate its molar mass (the mass of one mole of atoms of that element). Then, add up the molar masses of all the elements in the compound to find the total molar mass of the compound. Finally, apply the formula by taking the molar mass of the specific element and dividing it by the total molar mass of the compound. Multiply the result by 100 to express the ratio as a percentage. This calculation helps determine the relative abundance of each element in the compound based on their masses.
The probable question may be:
To find the percent by mass of a compound if you are given the formula, divide the molar mass of that element in one mole of the compound by the total molar mass of the compound, multiplied by 100.
True/False.
Which compounds will be soluble in water?
Answer:
salt
Explanation:
A solution of HCl gas dissolved in water (sold commercially as "muriatic acid," a solution used to clean masonry surfaces) has 20.22 g of HCl per 100.0 g of solution, and its density is 1.10 g/mL.
What is its molarity?
What is its mole fraction?
Answer:
[HCl] = 6.09 M
Xm HCl = 0.11
Explanation:
Let's analyse data:
20.22 g of solute / 100 g of solution
Solution's density = 1.10 g/mL
As we have the mass of solution and its density we determine solution's volume to stablish [M]
Density = Mass / volume → 1.10 g/mL = 100 g / Volume
100 g / 1.10g/mL = 90.9 mL
Let's convert the volume to L → 90.9 mL . 1L/ 1000mL = 0.0909L
We convert the mass of solute to moles → 20.22 g . 1mol/ 36.45g =
0.554 moles
[M] = Molarity (moles of solute /1L of solution) = 0.554 mol/0.0909L = 6.09M
Mole fraction (Xm) = Moles of solute / Total moles
Total moles = Moles of solute + Moles of solvent
Mass of solvent = Mass of solution - Mass of solute
Mass of solvent = 100 g - 20.22 g = 79.78g
We convert the mass to moles → 79.78 g / 18g/mol = 4.43 moles
Total moles = 4.43 moles + 0.554moles = 4.984 moles
Xm = 0.554 / 4.984 = 0.11
Final answer:
To find the molarity and mole fraction of the HCl solution, we calculate the molarity as 6.09 M and the mole fraction of HCl as 0.111 based on the given mass of HCl, solution density, and total solution mass.
Explanation:
To determine the molarity and mole fraction of a solution of HCl gas dissolved in water, we first need to calculate the mass of the solution and then convert the mass of HCl to moles. Given that the solution has 20.22 g of HCl per 100.0 g of solution, and its density is 1.10 g/mL, we can calculate the molarity and mole fraction as follows:
Calculating Molarity
Convert the mass of HCl to moles using the molar mass of HCl (36.46 g/mol):
20.22 g HCl * (1 mol HCl / 36.46 g) = 0.554 moles HCl. To find the volume of the solution, use the density and total mass:
100.0 g solution * (1 mL / 1.10 g) = 90.91 mL. Convert this to liters: 90.91 mL = 0.09091 L. Calculate molarity (M):
M = moles of solute / liters of solution = 0.554 moles / 0.09091 L = 6.09 M.
Calculating Mole Fraction
The mole fraction of HCl (XHCl) requires the number of moles of water:
(79.78 g water / 18.015 g/mol) = 4.43 moles of water. Calculate mole fraction of HCl:
XHCl = moles of HCl / (moles of HCl + moles of water) = 0.554 / (0.554 + 4.43) = 0.111.
The pressure of a gas changes from 120kPa to 50kPa. The volume changes from 45L to 40L. If the initial temperature is 81°C, what is the final temperature in Kelvin units?
Answer:
The final temperature is 131 K
Explanation:
Step 1: Data given
The initial pressure = 120 kPa = 1.18431 atm
The final pressure = 50 kPa = 0.493462 atm
The initial volume = 45 L
The final volume = 40 L
The initial temperature = 81 °C = 354 K
Step 2: Calculate the final temperature
(P1*V1)/T1 = (P2*V2)/T2
⇒with P1 = the initial pressure = 1.18431 atm
⇒with V1 = the initial volume = 45 L
⇒with T1 = the initial temperature = 354 K
⇒with P2 = the final pressure = 0.493462 atm
⇒with V2 = the final volume = 40 L
⇒with T2 = the final temperature = ?
(1.18431 * 45)/354 = (0.493462*40)/T2
0.15054788 = 19.73848/T2
T2 = 19.73848/0.15054788
T2 = 131 K
The final temperature is 131 K
Final answer:
To determine the final temperature of a gas with given initial and final pressures and volumes, one applies the combined gas law. After converting the initial Celsius temperature to Kelvin, the final temperature is calculated to be 262.33K.
Explanation:
The problem at hand involves the application of the combined gas law, which allows us to calculate changes in a gas's condition. This law is represented as (P1 * V1) / T1 = (P2 * V2) / T2, where P stands for pressure, V for volume, and T for temperature in Kelvin. Given that the pressure of a gas changes from 120kPa to 50kPa and its volume changes from 45L to 40L, with an initial temperature of 81°C (which is 354.15K), we can find the final temperature.
To solve, we start with the conversion of temperatures to Kelvin and then apply the formula. The rearranged formula to find the final temperature (T2) is T2 = ((P2 * V2) * T1) / (P1 * V1). By substituting the given values, T2 = ((50kPa * 40L) * 354.15K) / (120kPa * 45L), we get a final temperature of 262.33K.
The Na /K pump generates a membrane potential across the plasma membrane (PM) of the cell by transporting Na and K across the PM. The action of this pump results in the cell having a slightly ____________ charge inside the cell compared to the extracellular space.
Answer:
NEGATIVE CHARGE can best fill in the gap
Explanation:
The Na /K pump functions to maintain resting potential so that the cells will be kept in a state of a low concentration of sodium ions and high levels of potassium ions within the cell.
The processes of Na - K pump illustrates active transport since it moves Na+ and K+ ions against their concentration gradient. The energy required is supplied by the breakdown of ATP (adenosine triphosphate) to ADP (adenosine diphosphate). In nerve cells the pump is used to generate gradients of both sodium and potassium ions.
How does the sodium-potassium pump contribute to the net negative charge of the interior of the cell?
The sodium-potassium pump forces out three (positive) Na+ ions for every two (positive) K+ ions it pumps in, thus the cell loses a positive charge at every cycle of the pump.
Which planets are composed more of gas than liquids and solids? A. Venus, Jupiter, Neptune, and Mercury B. Jupiter, Saturn, Uranus, and Neptune C. Venus, Jupiter, Uranus, and Neptune D. Jupiter, Saturn, Neptune, and Mercury
Answer:
the answer is b :)
Explanation:
Answer: B
Explanation:
I just had this question on Study Island.
A 2.00-L glass soda bottle filled only with air is tightly capped at 25°C and 728.0 mmHg. If the bottle is placed in water at 65°C, what is the pressure in the bottle?
Answer:
The pressure in the bottle is 826 mmHg
Explanation:
In this case it is assumed that the volume of the soda bottle does not change, so it remains constant with a value of 2.00 L. Then it is possible to apply the Gay Lussac law.
This law indicates that when there is a constant volume, as the temperature increases, the gas pressure increases. And when the temperature decreases, gas pressure decreases. That is, the gas pressure is directly proportional to its temperature.
Gay-Lussac's law can be expressed mathematically as follows:
[tex]\frac{P}{T}=k[/tex]
Where P = pressure, T = temperature and K = Constant
Having a gas that is at a pressure P1 and a temperature T1, as the temperature varies to a new T2 value, then the pressure will change to P2. It is then fulfilled:
[tex]\frac{P1}{T1} =\frac{P2}{T2}[/tex]
Remember that the temperature must be in degrees Kelvin (° K) and that 0 ° C is 273.15 ° K
In this case you know:
P1= 728 mmHgT1= 25°C+273.15°K= 298.15°KP2= ?T2= 65°C+273.15°K= 338.15°KReplacing:
[tex]\frac{728 mmHg}{298.15K} =\frac{P2}{338.15K}[/tex]
Resolving you get:
[tex]\frac{728 mmHg}{298.15K} *338.15K=P2[/tex]
P2=825.67 mmHg≅826 mmHg
The pressure in the bottle is 826 mmHg
The pressure of the bottle is 825.7 mmHg
The parameters given in the question are
Pressure 1= 728 mmHg
Temperature 1= 25°C
= 25+273
T1= 298K
Temperature 2= 65°C
= 65 +273
= 338K
P1/T1= P2/T2
728/298= P2/338
Cross multiply
298 × P2= 728 × 338
298 × P2= 246,064
P2= 246,064/298
P2= 825.7
Hence the pressure in the bottle is 825.7 mmHg
Please see the link below for more information
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Which of the soutions would have the HIGHEST hydrogen ion concentration?
Solution with a pH = 1
Solution with a pH = 12
Solution with a pH = 7
Solution with a pH = 9
Solution with a pH = 5
Answer:
Solution with a pH = 1
Explanation:
So the pH equation is pH = -log[H+]. To get the [H+] (hydrogen ion concentration), you rearrange to get [H+] = 10^-pH.
Solution with a pH = 1 , [H+] = .1 M
Solution with a pH = 12 , [H+] = 1*10^-12 M
Solution with a pH = 7 , [H+] = 1*10^-7 M
Solution with a pH = 9 , [H+] = 1*10^-9 M
Solution with a pH = 5, [H+] = 1*10^-5 M
Another way to get the answer: a high hydrogen ion concentration means that the solution should be more acidic. The most acidic pH of the 5 solutions is the one with a pH = 1.
Final answer:
The solution with a pH of 1 would have the highest hydrogen ion concentration, indicating it is the most acidic among the given options.
Explanation:
Out of the provided pH values, which solution would have the highest concentration of hydrogen ions? An indicator of how basic or acidic a solution is is the pH scale. High pH solutions are more basic, whereas low pH solutions are more acidic.
Because the pH scale is logarithmic, every pH value below 7 is ten times more acidic than the value immediately above it. For the options given, a pH of 1 indicates the highest acidity, implying the highest hydrogen ion concentration. This is due to the following relationship: pH = -log[H₃O⁺], where [H₃O⁺] represents the hydrogen ion concentration.
Therefore, a solution with a pH of 1 has a hydrogen ion concentration of 1.0 x 10⁻¹M, and is acidic.
The decay series for 238 92U is represented in Figure 19.1. Write the balanced nuclear equation for each of the following radioactive decays. a. Alpha-particle production by 226 88 Ra b. Beta-particle production by 214 82 Pb
Answer: The decay process of the radioisotopes are written below.
Explanation:
For the given options:
Option a:Alpha decay is defined as the process in which the nucleus of an atom disintegrates into two particles. The first one which is the alpha particle consists of two protons and two neutrons, also known as helium nucleus. The second particle is the daughter nuclei which is the original nucleus minus the alpha particle released.
[tex]_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha[/tex]
The chemical equation for the alpha decay process of Ra-226 isotope follows:
[tex]_{88}^{226}\textrm{Ra}\rightarrow _{86}^{222}\textrm{Rn}+_2^4\alpha[/tex]
Option b:Beta decay is defined as the process in which the neutrons get converted into an electron and a proton. The released electron is known as the beta particle. In this process, the atomic number of the daughter nuclei gets increased by a factor of 1 but the mass number remains the same.
[tex]_Z^A\textrm{X}\rightarrow _{Z+1}^{A}\textrm{Y}+_{-1}^0\beta[/tex]
The chemical equation for the alpha decay process of Pb-214 isotope follows:
[tex]_{82}^{214}\textrm{Pb}\rightarrow _{83}^{214}\textrm{Bi}+_{-1}^0\beta[/tex]
Hence, the decay process of the radioisotopes are written above.
A 0.10 mol sample of each of the four species in the reaction represented above is injected into a rigid, previously evacuated 1.0 L container. Which of the following species will have the highest concentration when the system reaches equilibrium?
a.H2S(g)
b.CH4(g)
c.CS2(g)
d.H2(g)
The question is incomplete. complete question is;
A 0.10 mol sample of each of the four species in the reaction represented above is injected into a rigid, previously evacuated 1.0 L container. Which of the following species will have the highest concentration when the system reaches equilibrium?
[tex]2H_2S+CH_4\rightleftharpoons CS_2(g)+4H_2(g)[/tex]
[tex]K_c=3.4\times 10^{-4}[/tex]
a.[tex]H_2S(g) [/tex]
b.[tex]CH_4(g) [/tex]
c.[tex]CS_2(g) [/tex]
d.[tex]H_2(g)[/tex]
Answer:
The correct answer is option a.
Explanation:
[tex]2H_2S+CH_4\rightleftharpoons CS_2(g)+4H_2(g)[/tex]
The equilibrium constant of the reaction= [tex]K_c=3.4\times 10^{-4}[/tex]
Concentration of the species initially:
[tex][H_2S]=\frac{0.10 mol}{1.0 L}=0.10 M[/tex]
[tex][CH_4]=\frac{0.10 mol}{1.0 L}=0.10 M[/tex]
[tex][CS_2]=\frac{0.10 mol}{1.0 L}=0.10 M[/tex]
[tex][H_2]=\frac{0.10 mol}{1.0 L}=0.10 M[/tex]
The equilibrium quotient of the reaction is :
[tex]Q_c=\frac{[CS_2][H_2]^4}{[H_2S]^2[CH_4]}[/tex]
[tex]=\frac{(0.10M)(0.10 M)^4}{(0.10 M)^2(0.10 M)}=0.01[/tex]
[tex]Q_c>K_c[/tex] (reaction will go backward)
[tex]2H_2S+CH_4\rightleftharpoons CS_2(g)+4H_2(g)[/tex]
Initially
0.10 M 0.10 M 0.10 M 0.10 M
At Equilibrium :
(0.10+2x) M (0.10+x) M (0.10-x) M (0.10-4x) M
[tex]K_c=\frac{[CS_2][H_2]^4}{[H_2S]^2[CH_4]}[/tex]
[tex]3.4\times 10^{-4}=\frac{(0.10-x)(0.10-4x)^4}{(0.10+2x)^2(0.10+x)}[/tex]
Solving formx:
x = 0.099 M
As we can see that from the reaction at equilibrium, the concentration of hydrogen sulfide will be highest:
[tex]=[H_2S]=(0.10+2x) M=(0.10+2\times 0.099) M=0.298 M[/tex]
The highest concentration at equilibrium has been of hydrogen sulfide. Thus, option A is correct.
The moles of reactants in the reaction has been 0.10 mol for each reactant. The balanced equation for the reaction has been:
[tex]\rm 2\;H_2S\;+\;CH_4\;\leftrightharpoons CS_2\;+\;4\;H_2[/tex]
The equilibrium quotient Q, for the reaction, has been given as:
[tex]Q=\dfrac{[CS_2]\;[H_2]^4}{[H_2S]^2\;[CH_4]}[/tex]
Computation for Equilibrium quotient :The equilibrium concentration of the reaction has been given in the image attached.
The initial value of equilibrium quotient, Qi has been:
[tex]Q_i=\dfrac{[0.1]\;\times\;[0.1]^4}{[0.1]^2\;[0.1]} \\Q_i=0.01[/tex]
The initial value of equilibrium quotient has been 0.01.
The equilibrium quotient, Ke value for equilibrium concentration:
[tex]3.4\;\times\;10 ^-^4=\dfrac{[0.10-x]\;[0.10-4x]^4}{[0.10+2x]^2\;[0.10 +x]} \\x=0.099\;M[/tex]
The concentration of compounds at equilibrium has been highest for hydrogen sulfide that is 0.298 M.
Thus, the highest concentration at equilibrium has been of hydrogen sulfide. Thus, option A is correct.
For more information about equilibrium concentration, refer to the link:
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The ph of 0.010 m aqueous aniline is 8.32. What is the percentage protonated?
Answer : The percentage aniline protonated is, 0.0209 %
Explanation :
First we have to calculate the pOH.
[tex]pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-8.32\\\\pOH=5.68[/tex]
Now we have to calculate the hydroxide ion concentration.
[tex]pOH=-\log [OH^-][/tex]
[tex]5.68=-\log [OH^-][/tex]
[tex][OH^-]=2.09\times 10^{-6}M[/tex]
The equilibrium chemical reaction will be:
[tex]NH_3+H_2O\rightleftharpoons NH_4^++OH^-[/tex]
From the reaction we conclude that,
Concentration of [tex]OH^-[/tex] ion = Concentration of [tex]NH_4^+[/tex] ion = [tex]2.09\times 10^{-6}M[/tex]
Now we have to calculate the percentage aniline protonated.
[tex]\text{percentage aniline protonated}=\frac{2.09\times 10^{-6}M}{0.010M}\times 100[/tex]
[tex]\text{percentage aniline protonated}=0.0209\%[/tex]
Thus, the percentage aniline protonated is, 0.0209 %
when the temperature of a gas changes, it's volume decreases from 12 cm3 to 7 cm3 if the final temperature is measured to be 18°C what is the initial temperature in Kelvin units?
pls help :)
Answer:
The initial temperature is 499 K
Explanation:
Step 1: Data given
initial volume = 12 cm3 = 12 mL
Final volume = 7 cm3 = 7mL
The final temperature = 18 °C = 291 K
Step 2: Calculate the initial temperature
V1/T1 = V2/T2
⇒with V1 = the initial volume = 0.012 L
⇒with T1 = the initial volume = ?
⇒with V2 = the final volume 0.007 L
⇒with T2 = The final temperature = 291 K
0.012 / T1 = 0.007 / 291
0.012/T1 = 2.4055*10^-5
T1 = 0.012/2.4055*10^-5
T1 = 499 K
The initial temperature is 499 K
An 8.10-g sample of was placed in an evacuated container, where it decomposed at 590°C according to the following reaction: At equilibrium the total pressure and the density of the gaseous mixture were 1.83 atm and 1.57 g/L respectively. Calculate for this reaction.
Correct question:
An 8.10-g sample of SO3 was placed in an evacuated container, where it decomposed at 590°C according to the following reaction:
SO3(g) <-----> SO2(g) + 1/2 O2 (g)
At equilibrium the total pressure and the density of the gaseous mixture were 1.83 atm and 1.57 g/L respectively. Calculate Kp for this reaction
Answer:
Kp for this reaction is 0.149atm
Explanation:
Given details
The state reaction
SO3(g) <-----> SO2(g) + 1/2 O2 (g)
Density = 1.57 g/L
Temperature = 590°C = 863K
The given mass of SO3 is 8.10g
The molar mass of SO3 is
S + 3O = {(32) + 3(16)} = 80g/mol
Numbers of mole =
Given mass/molar mass = 8.10/80
Numbers of mole of SO3 = 0.1013mol
From density = mass/volume
Volume V = 8.10/1.56 = 5.2L
Initial pressure from PV = nRT
R = Universal gas constant
R = 0.0821 atm/K/mol
P = (0.1013*0.0821*863)/5.2
P = 1.38 atm
At equilibrium
moles SO3 = 0.10 - X
moles SO2 = X
moles O2 = X/2
moles total = (0.10 - X) + X + X/2
Total mole = 0.10 + X/2
Ptot = (0.10 + X/2)*0.0821*863/5.2 = 1.83
(0.10 + X/2)* 70.8523 = 9.516
X/2 = 0.1343 -0.10 = 0.0343
X = 0.0686
At equilibrium
moles SO3 = 0.10 - X = 0.10 - 0.0686 = 0.0314
moles SO2 = X = 0.0686
moles O2 = X/2 = 0.0343
moles total = 0.10 + X/2 = 0.10 + 0.0343 = 0.1343
P(SO3) = Ptot*X(SO3) = 1.83*0.0314/0.1343 = 0.428atm
P(SO2) = 1.83*0.0686/0.1343 = 0.935atm
P(O2) = 1.83*0.0343/0.1343 = 0.467atm
Kp for this reaction is
Kp = [P(SO2)*P(O2)^1/2]/P(SO3)
Kp = {0.935*(0.467)^0.5}/0.428
Kp = 0.149atm
The______of water molecules and the hydrogen bonds between water molecules explain most of water's life-supporting properties.The_____of water molecules to each other helps transport water from the roots to the leaves in plants.
Polarity
Cohesion
Explanation:
One molecule of water joins with four other water molecule by hydrogen bonds. In a water molecule, one end has positive charge and the other end has negative charge. This difference in charge creates polarity in the molecule.
The cohesion of water molecules helps transport water from roots to the leaves in plants. Plants absorb water from the soil by osmosis. They absorb mineral ions by active transport, against the concentration gradient. Root hair cells are adapted for taking up water and mineral ions by having a large surface area to increase the rate of absorption.
Answer: Cohesion
Explanation:
Cohesion is a measure of how well molecules stick to each other. Water molecules is a typical example of Cohesion.
Hydrogen bonds are formed between each water molecule, enabling them stick to each other strongly. Due to this sticky nature of water molecules, they form droplets on surfaces (e.g dew drops) and a dome like-shape when filling a container just before it overflows.
Cohesion also produces Surface Tension; a phenomenon that makes it possible for light objects like needle to float when placed gently and insects to walk on water.
Also aided by capillary action (the movement of a liquid across the surface of a solid caused by adhesion between the two), Cohesion makes it possible for water to be taken as single huge molecule from Xylem in the roots of plant to its leaves.
The combustion of glucose is represented by the following balanced equation: C6H12O6+6 O2→6 H2O+6 CO2. The reaction uses 1 gram of both C6H12O6 and O2. What is the percent yield if 0.45 g of H2O is produced? a 0.558% b 100% c 0.31% d 80%
Answer : The correct option is, (d) 80 %
Solution : Given,
Mass of [tex]C_6H_{12}O_6[/tex] = 1 g
Mass of [tex]O_2[/tex] = 1 g
Molar mass of [tex]C_6H_{12}O_6[/tex] = 180 g/mole
Molar mass of [tex]O_2[/tex] = 32 g/mole
Molar mass of [tex]H_2O[/tex] = 18 g/mole
First we have to calculate the moles of [tex]C_6H_{12}O_6[/tex] and [tex]O_2[/tex].
[tex]\text{ Moles of }C_6H_{12}O_6=\frac{\text{ Mass of }C_6H_{12}O_6}{\text{ Molar mass of }C_6H_{12}O_6}=\frac{1g}{180g/mole}=0.00555moles[/tex]
[tex]\text{ Moles of }O_2=\frac{\text{ Mass of }O_2}{\text{ Molar mass of }O_2}=\frac{1g}{32g/mole}=0.0312moles[/tex]
Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,
[tex]C_6H_{12}O_6+6O_2\rightarrow 6H_2O+6CO_2[/tex]
From the balanced reaction we conclude that
As, 6 mole of [tex]O_2[/tex] react with 1 mole of [tex]C_6H_{12}O_6[/tex]
So, 0.0312 moles of [tex]O_2[/tex] react with [tex]\frac{0.0312}{6}=0.0052[/tex] moles of [tex]C_6H_{12}O_6[/tex]
From this we conclude that, [tex]C_6H_{12}O_6[/tex] is an excess reagent because the given moles are greater than the required moles and [tex]O_2[/tex] is a limiting reagent and it limits the formation of product.
Now we have to calculate the moles of [tex]H_2O[/tex]
From the reaction, we conclude that
As, 6 mole of [tex]O_2[/tex] react to give 6 mole of [tex]H_2O[/tex]
So, 0.0312 mole of [tex]O_2[/tex] react to give 0.0312 mole of [tex]H_2O[/tex]
Now we have to calculate the mass of [tex]H_2O[/tex]
[tex]\text{ Mass of }H_2O=\text{ Moles of }H_2O\times \text{ Molar mass of }H_2O[/tex]
[tex]\text{ Mass of }H_2O=(0.0312moles)\times (18g/mole)=0.562g[/tex]
Theoretical yield of [tex]H_2O[/tex] = 0.562 g
Experimental yield of [tex]H_2O[/tex] = 0.45 g
Now we have to calculate the percent yield of the reaction.
[tex]\% \text{ yield of reaction}=\frac{\text{ Experimental yield of }H_2O}{\text{ Theoretical yield of }H_2O}\times 100[/tex]
[tex]\% \text{ yield of reaction}=\frac{0.45g}{0.562g}\times 100=80\%[/tex]
Therefore, the percent yield of reaction is, 80 %
Answer:
The yield would D. 80%!
Explanation:
Since 1 gram of O2 only produces 0.56 g of H2O, whereas 1 g of C6H12O6 produces 0.60 g of H2O, the O2 is the limiting reagent.
The molarity of an aqueous solution of nacl is defined as the
Answer: Number of moles of NaCl per liter of solution
Explanation: Molarity can be defined as the number of moles
of solute per liter of solution.
Therefore the molarity of an aqueous solution of NaCl is thus defined as the number of moles of NaCl per liter of solution.
22. Complete and balance the following acid-base equations: (a) A aqueous solution of HClO4 is added to an aqueous solution of LiOH. (b) Aqueous H2SO4 reacts with aqueous NaOH. (c) Ba(OH)2 solid reacts with HF gas.
Answer:
Answers are in the explanation
Explanation:
An acid-base equation in general is the reaction between an acid and a base that produce water and a salt. Thus:
a) HClO₄(aq) + LiOH(aq) → LiClO₄(aq) + H₂O(l)
Acid + Base → Salt + Water
b) H₂SO₄(aq) + 2NaOH(aq) → Na₂SO₄(aq) + 2H₂O(l)
Acid + Base → Salt + Water
c) 2HF(g) + Ba(OH)₂(s) → BaF₂ + 2H₂O
Acid + Base → Salt + Water
I hope it helps!
When we think about the carbon cycle and human activities, it is important to differentiate between facts and hypotheses. Which of the following is NOT a fact, but is a hypothesis? A. The amount of carbon dioxide in the atmosphere has increased since 1950. B. Increasing atmospheric carbon dioxide will cause mean global temperature to increase by 2 degrees Celsius over the next century. C. The burning of fossil fuels contributes substantially to the ongoing rise of atmospheric CO2. D. In the past, atmospheric CO2 levels reached levels higher than those observed today.
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.
Precipitation reactions and ionic equations
(look at attachment)
Answer:
Net ionic equation: 2OH⁻(aq) + Fe²⁺(aq) → Fe(OH)₂(s)
Net ionic equation: 2K⁺(aq) + CH₃COO⁻ (aq) + 2Na⁺(aq) + S⁻²(aq) → NO REACTION
Net ionic equation: CO₃⁻²(aq) + Pb⁺²(aq) → PbCO₃(s)
Explanation:
a. Solutions of calcium hydroxide and Iron (II) chloride are mixed:
We identify the reactants:
Ca(OH)₂ , FeCl₂
In excess, the Fe(OH)₂ can make precipitate
Salts from chlorides with elements from group II are soluble.
The reaction is: Ca(OH)₂(aq) + FeCl₂(aq) → Fe(OH)₂(s) + CaCl₂(aq)
Ca(OH)₂(aq) + FeCl₂(aq) → Fe(OH)₂(s) + CaCl₂(aq)
We dissociate the compounds, except for the solid
Ca²⁺(aq) + 2OH⁻(aq) + Fe²⁺(aq) + 2Cl⁻(aq) → Fe(OH)₂(s) + Ca²⁺ + 2Cl⁻(aq)
Net ionic equation: 2OH⁻(aq) + Fe²⁺(aq) → Fe(OH)₂(s)
b. Solutions of potassium acetate and sodium sulfide are mixed:
The reactants are: KCH₃COOH and Na₂S
In this case there are no precipitates, because all the salts are soluble
We make the complete reaction:
2KCH₃COO (aq) + Na₂S(aq) → K₂S(aq) + 2NaCH₃COO (aq)
Net ionic equation is:
2K⁺(aq) + CH₃COO⁻ (aq) + 2Na⁺(aq) + S⁻²(aq) → 2K⁺(aq) + S⁻²(aq) + 2Na⁺(aq) + CH₃COO⁻ (aq)
c. Solutions of ammonium carbonate and lead(II) nitrate are mixed:
In this case, the reactants are: (NH₄)₂CO₃ and Pb(NO₃)₂
All salts from nitrate are soluble.
Carbonate makes a precipitate when it bonds Pb.
The complete reaction is:
(NH₄)₂CO₃(aq) + Pb(NO₃)₂(aq) → PbCO₃(s) + 2NH₄NO₃(aq)
We dissociate all of the compounds, except for the solid in order to make the net ionic equation:
2NH₄⁺(aq) +CO₃⁻²(aq) + Pb⁺²(aq) +2NO₃⁻(aq) → PbCO₃(s) + 2NH₄⁺ (aq) + 2NO₃⁻(aq)
The net ionic equation is: CO₃⁻²(aq) + Pb⁺²(aq) → PbCO₃(s)
The ions that are repeated, are called spectators ions. We all cancel them.
How can you tell if a chemical compound is ionic or covalent by just looking at the formula?
Answer: Ionic compounds ( Metal + Non-metal), Covalent Compounds (Non-metal + Non metal ).
Explanation: Going by the definition, an ionic compound is formed when a chemical reaction occurs between a metal and a non-metal while a covalent compound is formed when a chemical reaction occurs between two non-metals.
Having a good knowledge of the periodic table, one can easily identify the metals and non-metals in each compound and thus tell if it is Ionic or Covalent.
By examining the formula of a chemical compound, one can tell if it is ionic or covalent. Ionic compounds consist of metals combined with nonmetals or polyatomic ions, whereas covalent compounds are formed from nonmetals only.
Explanation:To determine if a chemical compound is ionic or covalent just by looking at the formula, we consider the types of elements involved in the compound. Typically, ionic compounds are formed when a metal and a nonmetal react, resulting in the transfer of electrons and the formation of ions. For example, NaCl (sodium chloride) is an ionic compound because it consists of the metal sodium (Na) and the nonmetal chlorine (Cl).
In contrast, covalent compounds are formed when nonmetals bond together, leading to the sharing of electrons. An example of a covalent compound is H2O (water), which comprises the nonmetals hydrogen (H) and oxygen (O). Also, if the compound contains a recognizable polyatomic ion like NO3− (nitrate), which typically forms ionic bonds with metals, it can be identified as ionic. For instance, Ba(NO3)2 includes the nitrate ion and the metal barium (Ba), indicating an ionic compound.
Explain to Mark how composting can help reduce greenhouse gases
Explanation:
Compositing is the regulated breakdown of organic matter by microbes, aerobically. The major gas released from composting is carbon dioxide. This is different from landfills and manure piles where most of the breakdown of the organic matter happens, anaerobically because less oxygen penetrates the matter. Composting involves deliberate aeration of the decomposing matter. Anaerobic breakdown methane releases methane gas even more than carbon dioxide. Methane is four times more potent as a greenhouse gas than carbon dioxide. This is why composting is a good agricultural practice for mitigating climate change as compared to the use of landfills.
Answer:
Composting reduces the waste going to the landfill, which can lower methane emissions. It also promotes the growth of new plants and trees, which control the CO2 levels in the air. Mark could ask these two questions at the meeting:
What types of food waste will be composted?
How will the compost be used in the community?
Explanation:
This is the sample answer on edmentum
The volume of a sample of chlorine gas is 8.00 liters at 45.0 degrees Celsius and 0.966 atm. How many moles of chlorine are present in the sample? R = 0.0821 (atm)(L)(mol-1)(K-1)
Answer:
Number of moles of Cl₂ = 0.3 mol
Explanation:
Given data:
Number of moles of Cl₂ = ?
Pressure = 0.966 atm
Volume = 8.00 L
Temperature = 45°C
Solution:
The given problem will be solve by using general gas equation, which is,
PV = nRT
R = general gas constant (0.0821 atm.L/mol.K)
Now we will convert the °C into K.
Temperature = 45+ 273 = 318 K
Now we will put the values in formula.
n = PV/RT
n = 0.966 atm × 8.00 L / 318 K ×0.0821 atm.L/mol.K
n = 7.728/26.1078 /mol
n = 0.3 mol
Early life arose in an oxygen-free environment, but if any of these microbes had somehow come in contact with oxygen, the most likely effect would have been ________.
Answer:
the effect of oxygen on these types of microbes is it will kill them.
Explanation:
When oxygen present in the environment come in contact with anaerobe bacteria it kill them because oxygen in air act as excited oxygen singlet molecule which will react with the water present in the cell of bacteria and convert it into hydrogen peroxides and bacteria do not have any defense system from hydrogen peroxide and ultimately it kill the bacteria.
Calculate the pH after 0.018 mole of HCl is added to 1.00 L of each of the four solutions. (Assume that all solutions are at 25°C.) (a) 0.129 M acetic acid (HC2H3O2, Ka = 1.8 ✕ 10−5) (b) 0.129 M sodium acetate (NaC2H3O2) (c) pure H2O (d) 0.129 M HC2H3O2 and 0.129 M NaC2H3O2
Explanation:
Below are attachments containing the solution
The combustion of ethane ( C 2 H 6 ) produces carbon dioxide and steam. 2 C 2 H 6 ( g ) + 7 O 2 ( g ) ⟶ 4 CO 2 ( g ) + 6 H 2 O ( g ) How many moles of CO 2 are produced when 5.30 mol of ethane is burned in an excess of oxygen?
Answer:
10.6 moles of CO₂ are produced in this combustion
Explanation:
The combustion reaction is:
2C₂H₆ (g) + 7O₂ (g) ⟶ 4CO₂ (g) + 6H₂O (g)
We assume the ethane as the limiting reactant because the excersise states that the O₂ is in excess.
We make a rule of three:
2 moles of ethane can produce 4 moles of CO₂
Therefore 5.30 moles of ethane will produce (5.3 . 4) /2 = 10.6 moles
In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releasesA) acetylcholine.B) sodium ions.C) potassium ions.D) calcium ions.E) hydrogen ions
Answer:
Calcium ions.
Explanation:
The generation of the action potential helps in the transfer of information to the different body parts. This potential occurs to the difference in membrane potential inside and outside of the cell.
The sarcoplasmic reticulum is the homologous to the endoplasmic reticulum of the cells. The sarcoplasmic reticulum contains calcium ions in it and releases the stored calcium ions on the generation of the action potential. This calcium ion is important for the action of the actin and myosin.
Thus, the correct answer is option (D).
Boyle's law states that gas volume is Boyle's law states that gas volume is inversely proportional to temperature. directly proportional to pressure. inversely proportional to pressure. directly proportional to temperature. both directly proportional to pressure and directly proportional to temperature.
Answer: Boyle's law states that gas volume is inversely proportional to pressure.
Explanation:
Boyle's law is one of the law used to determine the Ideal Gas equation.
This law states that pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles
Mathematically,
[tex]P\propto \frac{1}{V}[/tex] (at constant temperature and number of moles)
The above expression can also be written as:
[tex]P_1V_1=P_2V_2[/tex]
where,
[tex]P_1\text{ and }V_1[/tex] are initial pressure and volume of the gas
[tex]P_2\text{ and }V_2[/tex] are final pressure and volume of the gas
Hence, Boyle's law states that gas volume is inversely proportional to pressure.
Boyle's law states that at constant temperature, the volume of a fixed amount of gas is inversely proportional to its pressure. Thus, if the pressure on a gas increases, its volume decreases, and vice versa. This relationship is crucial for understanding gas behavior.
Boyle's law states that the volume of a given amount of gas held at constant temperature is inversely proportional to the pressure under which it is measured. This means if the pressure on a gas increases, its volume decreases, as long as the temperature and the amount of gas remain constant, and vice versa.
If we express this relationship mathematically:
V ∝ 1/P or PV = k (where k is a constant)
For example, if you double the pressure on a gas, its volume will decrease by half, provided the temperature stays the same. This principle is essential in understanding the behavior of gases in various conditions.
Choose the chemical equation that is correctly balanced. 2Ca(s) + Cl2(g) → CaCl2(s) 4Mg(s) + O2(g) → 2MgO(s) Li(s) + Cl2(g) → 2LiCl(s) C(s) + O2(g) → CO2(g)
Answer:
Last option C(s) + O2(g) → CO2(g)
Explanation:
The reactions are:
2Ca(s) + Cl2(g) → CaCl2(s)
4Mg(s) + O2(g) → 2MgO(s)
Li(s) + Cl2(g) → 2LiCl(s)
C(s) + O2(g) → CO2(g)
Let's count the atoms (check out the stoichiometry):
1. We have 2 Ca in reactant side and 2Cl, in product side we have 1 Ca and 2 Cl. UNBALANCED
2. We have 4 Mg in reactant side and 2 O. In product side we have 2 Mg and 2 O. UNBALANCED
3. In reactant side we have 1 Li and 2 Cl. Then, in product side we have 2Li and 2Cl. UNBALANCED
C(s) + O2(g) → CO2(g)
1 C and 2 O ⇒ 1 C and 2 O Correctly balanced
The chemical equation [tex]\( \text{C(s)} + \text{O}_2\text{(g)} \rightarrow \text{CO}_2\text{(g)} \)[/tex] is correctly balanced. The correct option is (D).
To determine which chemical equation is correctly balanced, we need to ensure that the number of atoms for each element is the same on both sides of the equation. Let’s examine each option:
A) [tex]\( 2\text{Ca(s)} + \text{Cl}_2\text{(g)} \rightarrow \text{CaCl}_2\text{(s)} \)[/tex]
- Reactants: 2 Ca and 2 Cl
- Products: 1 Ca and 2 Cl
In this equation, the calcium (Ca) atoms are not balanced (2 Ca atoms on the left vs. 1 Ca atom on the right).
This equation is not balanced.
B) [tex]\( 4\text{Mg(s)} + \text{O}_2\text{(g)} \rightarrow 2\text{MgO(s)} \)[/tex]
- Reactants: 4 Mg and 2 O
- Products: 2 Mg and 2 O
In this equation, the magnesium (Mg) atoms are not balanced (4 Mg atoms on the left vs. 2 Mg atoms on the right).
This equation is not balanced.
C) [tex]\( \text{Li(s)} + \text{Cl}_2\text{(g)} \rightarrow 2\text{LiCl(s)} \)[/tex]
- Reactants: 1 Li and 2 Cl
- Products: 2 Li and 2 Cl
In this equation, the lithium (Li) atoms are not balanced (1 Li atom on the left vs. 2 Li atoms on the right).
This equation is not balanced.
D) [tex]\( \text{C(s)} + \text{O}_2\text{(g)} \rightarrow \text{CO}_2\text{(g)} \)[/tex]
- Reactants: 1 C and 2 O
- Products: 1 C and 2 O
In this equation, both carbon (C) and oxygen (O) atoms are balanced.
After analyzing the chemical equations, the only equation that is correctly balanced is:
[tex]\*\*D) \( \text{C(s)} + \text{O}_2\text{(g)} \rightarrow \text{CO}_2\text{(g)} \)\*\*[/tex]
To verify that the equation is balanced:
Carbon [tex](C)[/tex]:
- Reactants: 1 atom
- Products: 1 atom
Oxygen [tex](O)[/tex]:
- Reactants: 2 atoms
- Products: 2 atoms
Since the number of atoms for each element is the same on both sides of the equation, it confirms that option D is the correct and balanced chemical equation.
The complete question is:
Choose the chemical equation that is correctly balanced.
A) [tex]2Ca(s) + Cl_2(g) \rightarrow CaCl_2(s)[/tex]
B) [tex]4Mg(s) + O_2(g) \rightarrow 2MgO(s)[/tex]
C) [tex]Li(s) + Cl_2(g) \rightarrow 2LiCl(s)[/tex]
D) [tex]C(s) + O_2(g) \rightarrow CO_2(g)[/tex]
2 SO2(g) + O2(g) 2 SO3(g) Assume that Kc = 0.0680 for the gas phase reaction above. Calculate the corresponding value of Kp for this reaction at 84.5°C.
Answer: The corresponding value of [tex]K_p[/tex] for this reaction at 84.5°C is 0.00232
Explanation:
[tex]2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)[/tex]
Relation of with is given by the formula:
[tex]K_p=K_c(RT)^{\Delta ng}[/tex]
where,
= equilibrium constant in terms of partial pressure = ?
[tex]K_c[/tex] = equilibrium constant in terms of concentration = 0.0680
R = Gas constant = [tex]0.0821\text{ L atm }mol^{-1}K^{-1}[/tex]
T = temperature =[tex]84.5^0C=(273+84.5)K=357.5K[/tex]
[tex]\Delta n_g[/tex] = change in number of moles of gas particles = [tex]n_{products}-n_{reactants}=2-3=-1[/tex]
Putting values in above equation, we get:
[tex]K_p=0.0680\times (0.0821\times 357.5)^{-1}\\\\K_p=0.00232[/tex]
Thus the corresponding value of [tex]K_p[/tex] for this reaction at 84.5°C is 0.00232
How many hours will it take for the concentration of methyl isonitrile to drop to 14.0 %% of its initial value?
This is an incomplete question, here is a complete question.
The rearrangement of methyl isonitrile (CH₃NC) to acetonitrile (CH₃NC) is a first-order reaction and has a rate constant of 5.11 × 10⁻⁵ s⁻¹ at 472 K. If the initial concentration of CH₃NC is 3.00 × 10⁻² M :
How many hours will it take for the concentration of methyl isonitrile to drop to 14.0 % of its initial value?
Answer : The time taken will be, 10.7 hours
Explanation :
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant = [tex]5.11\times 10^{-5}s^{-1}[/tex]
t = time passed by the sample = ?
a = let initial amount of the reactant = 100
a - x = amount left after decay process = 14 % of 100 = 14
Now put all the given values in above equation, we get
[tex]t=\frac{2.303}{5.11\times 10^{-5}}\log\frac{100}{14}[/tex]
[tex]t=38482.72s=\frac{38482.72}{3600}=10.7hr[/tex]
Therefore, the time taken will be, 10.7 hours
hat is the relationship between the vapor pressure of a liquid and the measured pressure of the gas above the liquid at a given temperature in a closed system?
Answer:
In a closed system the vapor pressure and the measured pressure of a gas increases.
Explanation:
as the pressure of the liquid increases the measured pressures also increases with a given temperature.