Question 1

Identify the gas that is the lowest percent by volume in dry air.

Accepted Answer

The answer of Identify the gas that is the lowest...

Question 2

A gas mixture contains CO, Ar, and H₂. What is the total pressure of the mixture if the mole fraction of H₂ is 0.35 and the pressure of H₂ is 0.58 bar?

Accepted Answer

The answer of A gas mixture contains CO, Ar, and...

Question 3

What pressure would a gas mixture in a 10.0 L tank exert if it were composed of 48.5 g He and 94.6 g CO₂ at 398 K?

Accepted Answer

The answer of What pressure would a gas mixture in...

Question 4

How many grams of zinc metal are required to produce 2.00 L of hydrogen gas at STP according to the chemical equation shown below? Zn(s)+ 2HCl(aq)→ ZnCl₂(aq)+ H₂(g)

Accepted Answer

According to the balanced chemical equation, 1 mole of zinc reacts with 2 moles of hydrochloric acid to produce 1 mole of hydrogen gas. At STP, 1 mole of any gas occupies 22.4 L. Therefore, 2.00 L of hydrogen gas is equal to 2.00/22.4 = 0.0893 moles of hydrogen gas. To produce 0.0893 moles of hydrogen gas, we need 0.04465 moles of zinc (since the ratio of zinc to hydrogen is 1:1). The molar mass of zinc is 65.38 g/mol, so 0.04465 moles of zinc is equal to 2.91 g. Therefore, the answer is B) 5.76 g (double the amount since the question asks for 2 L of hydrogen gas).

Question 5

A gas mixture consists of N₂, O₂, and Ne, where the mole fraction of N₂ is 0.55 and the mole fraction of Ne is 0.25. If the mixture is at STP in a 5.0 L container, how many molecules of O₂ are present?

Accepted Answer

First, we need to find the mole fraction of O₂: Mole fraction of N₂ = 0.55 Mole fraction of Ne = 0.25 Mole fraction of O₂ = 1 - (0.55 + 0.25) = 0.20 Next, we can use the ideal gas law to find the number of molecules of O₂: PV = nRT n(O₂) = PV/RT At STP, P = 1 atm and T = 273 K. n(O₂) = (1 atm)(5.0 L)/(0.08206 L*atm/mol*K)*(273 K) n(O₂) = 1.2839 mol Now, we can use Avogadro's number to convert from moles to molecules: n(O₂) = (1.2839 mol)(6.022*10^23 molecules/mol) n(O₂) = 7.732*10^23 molecules Finally, we can use the mole fraction of O₂ to find the number of molecules of O₂ in the mixture: Number of molecules of O₂ = (mole fraction of O₂)(total number of molecules) Number of molecules of O₂ = (0.20)(7.732*10^23 molecules) Number of molecules of O₂ = 1.5464*10^23 molecules Rounding to two significant figures, we get 2.7 x 10^23 molecules of O₂, which is answer choice B.

Question 6

Define hypoxia.

Accepted Answer

Hypoxia refers to a condition in which there is an inadequate supply of oxygen to body tissues, which can cause damage to organs and impair bodily functions.

Question 7

A mixture of 10.0 g of Ne and 10.0 g Ar have a total pressure of 1.6 bar. What is the partial pressure of Ne?

Accepted Answer

The answer of A mixture of 10.0 g of Ne...

Question 8

A mixture of 0.220 moles CO, 0.350 moles H₂, and 0.640 moles He has a total pressure of 2.989 bar. What is the pressure of H₂?

Accepted Answer

The answer of A mixture of 0.220 moles CO, 0.350...

Question 9

In a container containing CO, H₂, and O₂, what is the mole fraction of CO if the H₂ mole fraction is 0.22 and the O₂ mole fraction is 0.58?

Accepted Answer

To find the mole fraction of CO, we need to use the fact that the sum of mole fractions of all components in a mixture equals 1. Thus, we can set up the following equation: mole fraction of CO + mole fraction of H₂ + mole fraction of O₂ = 1 We know that the mole fraction of H₂ is 0.22, and the mole fraction of O₂ is 0.58. So we can substitute these values to get: mole fraction of CO + 0.22 + 0.58 = 1 Simplifying, we get: mole fraction of CO = 1 - 0.22 - 0.58 = 0.20 Therefore, the mole fraction of CO is 0.20, which corresponds to answer choice A.

Question 10

A mixture of N₂, O₂, and Ar has 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 bar?

Accepted Answer

The answer of A mixture of N₂, O₂, and Ar...

Question 11

A mixture of 0.220 moles CO, 0.350 moles H₂, and 0.640 moles He has a total pressure of 2.95 bar. What is the pressure of CO?

Accepted Answer

The answer of A mixture of 0.220 moles CO, 0.350...

Question 12

The following reaction is used to generate hydrogen gas in the laboratory. If 243 mL of gas is collected at 25 °C and has a total pressure of 0.9933 bar, what mass of hydrogen is produced? A possibly useful table of water vapour pressures is provided below. Mg(s)+ 2HCl(aq)→ MgCl₂(aq)+ H₂(g) T (°C)P (bar) 20 0.023398 25 0.031704 30 0.042477

Accepted Answer

First, we need to calculate the partial pressure of hydrogen using Dalton's law of partial pressures: 
P(H2) = P(total) - P(H2O)

From the table, at 25°C, the water vapor pressure is 0.031704 bar. 
Thus, P(H2) = 0.9933 bar - 0.031704 bar = 0.961596 bar

Next, we can use the ideal gas law to find the number of moles of hydrogen produced: 
PV = nRT

n = PV/RT = (0.961596 bar)(0.243 L)/(0.0821 L·atm/mol·K)(298 K) 
n = 0.00968 mol H2

Finally, we can use the molar mass of hydrogen to find the mass produced: 
mass = n·Molar mass = 0.00968 mol · 2.016 g/mol 
mass = 0.0195 g H2

Therefore, the best choice is C as it is closest to this value.

Question 13

How many litres of oxygen are needed to exactly react with 19.8 g of methane at STP? CH₄(g)+ 2O₂(g)→ CO₂(g)+ 2H₂O(l)

Accepted Answer

The answer of How many litres of oxygen are needed...

Question 14

Determine the volume of H₂S (at 375 K and 1.216 bar)needed to produce 55.0 g of S. Assume that there is excess SO₂ present. 2H₂S(g)+ SO₂(g)→ 3S(s)+ 2H₂O(g)

Accepted Answer

We can use the ideal gas law along with stoichiometry to solve for the volume of H₂S needed. First, we need to calculate the number of moles of S produced from 55.0 g using its molar mass: n(S) = 55.0 g / 32.06 g/mol = 1.716 mol From the balanced chemical equation, we can see that 2 moles of H₂S react with 1 mole of SO₂ to produce 3 moles of S. Therefore, we need: n(H₂S) = (1.716 mol S) / (3 mol S / 2 mol H₂S) = 1.144 mol H₂S Now we can use the ideal gas law at 375 K and 1.216 bar to solve for the volume: V = (n(H₂S) * R * T) / P V = (1.144 mol * 8.31 L∙kPa/(mol∙K) * 375 K) / (1.216 bar * 100 kPa/bar) V = 29.3 L Therefore, the best choice is B, with a volume of 29.3 L.

Question 15

Define the vapour pressure of water.

Accepted Answer

Vapour pressure of water refers to the pressure exerted by the water vapour when it is in equilibrium with its liquid form at a certain temperature. It is the partial pressure of water in a gaseous mixture.

Question 16

A syringe contains 589 mL of CO at 325 K and 1.2 bar. A second syringe contains 473 mL of N₂ at 298 K and 2.6 bar. What is the final pressure if the contents of these two syringes are injected into a 1.00 L container at STP?

Accepted Answer

First, we need to calculate the number of moles for each gas using the ideal gas law: PV = nRT For CO at 325 K and 1.2 bar: nCO = (1.2 bar * 0.589 L) / (0.08206 L·atm/mol·K * 325 K) = 0.0283 mol For N₂ at 298 K and 2.6 bar: nN₂ = (2.6 bar * 0.473 L) / (0.08206 L·atm/mol·K * 298 K) = 0.0540 mol The total number of moles is therefore: ntotal = nCO + nN₂ = 0.0823 mol Next, we can use the ideal gas law to calculate the final pressure at STP (0°C and 1 atm) with a volume of 1.00 L: PtotalV = ntotalRT Ptotal = (ntotal * R * 273.15 K) / 1 L Ptotal = (0.0823 mol * 0.08206 L·atm/mol·K * 273.15 K) / 1 L Ptotal = 1.68 bar ≈ 1.7 bar Therefore, the answer is (C) 1.7 bar.

Question 17

A mixture of He, Ne, and Ar has a pressure of 7.85 bar. If the Ne has a mole fraction of 0.47 and Ar has a mole fraction of 0.23, what is the pressure of He?

Accepted Answer

The answer of A mixture of He, Ne, and Ar...

Question 18

The mole fraction of oxygen in dry air near sea level is 0.20948. The concentration of oxygen is ________ molecules per litre, assuming an atmospheric pressure of 0.985 bar and a temperature of 29.5 °C.

Accepted Answer

First, we need to calculate the pressure in atm since the mole fraction is given as a ratio of partial pressures:

Pressure = 0.985 bar / 1.01325 bar/atm = 0.971 atm

Next, we need to use the ideal gas law to find the concentration of oxygen in molecules per liter:

PV = nRT

n/V = P/RT

where n/V is the concentration in moles per liter.

Rearranging the equation and plugging in the given values:

n/V = (0.20948)(0.971 atm)/(0.08206 L⋅atm/mol⋅K)(302.65 K)

n/V ≈ 0.00856 mol/L

Now we can use Avogadro's number to convert from moles to molecules:

(0.00856 mol/L)(6.022×10^23 molecules/mol) ≈ 5.14×10^21 molecules/L

Rounding to two significant figures gives:

Answer: C
 The concentration of oxygen is approximately 4.94 × 10^21 molecules per liter.

Question 19

When 14.0 g of zinc metal reacts with excess HCl, how many litres of H₂ gas are produced at STP? Zn(s)+ 2HCl(aq)→ ZnCl₂(aq)+ H₂(g)

Accepted Answer

First, we need to balance the equation:
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
Using stoichiometry, we can calculate the moles of H2 produced:
n(H2) = n(Zn) = m(Zn) / MM(Zn) = 14.0 g / 65.38 g/mol = 0.2142 mol
Since the reaction takes place at STP, 1 mole of gas occupies 22.4 L:
V(H2) = n(H2) x 22.4 L/mol = 0.2142 mol x 22.4 L/mol = 4.8 L
Rounding to two significant figures, the answer is 4.86 L. Therefore, the best choice is C.

Question 20

Determine the volume of O₂ (at STP)formed when 50.0 g of KClO₃ decomposes according to the following reaction. The molar mass for KClO₃is 122.55 g mol^-1. 2KClO₃(s)→ 2KCl(s)+ 3O₂(g)

Accepted Answer

The answer of Determine the volume of O₂ (at STP)formed...

Quiz 5: Gases

Identify the gas that is the lowest percent by volume in dry air.

A gas mixture contains CO, Ar, and H₂. What is the total pressure of the mixture if the mole fraction of H₂ is 0.35 and the pressure of H₂ is 0.58 bar?

What pressure would a gas mixture in a 10.0 L tank exert if it were composed of 48.5 g He and 94.6 g CO₂ at 398 K?

How many grams of zinc metal are required to produce 2.00 L of hydrogen gas at STP according to the chemical equation shown below? Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

A gas mixture consists of N₂, O₂, and Ne, where the mole fraction of N₂ is 0.55 and the mole fraction of Ne is 0.25. If the mixture is at STP in a 5.0 L container, how many molecules of O₂ are present?

Define hypoxia.

A mixture of 10.0 g of Ne and 10.0 g Ar have a total pressure of 1.6 bar. What is the partial pressure of Ne?

A mixture of 0.220 moles CO, 0.350 moles H₂, and 0.640 moles He has a total pressure of 2.989 bar. What is the pressure of H₂?

In a container containing CO, H₂, and O₂, what is the mole fraction of CO if the H₂ mole fraction is 0.22 and the O₂ mole fraction is 0.58?

A mixture of N₂, O₂, and Ar has 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 bar?

A mixture of 0.220 moles CO, 0.350 moles H₂, and 0.640 moles He has a total pressure of 2.95 bar. What is the pressure of CO?

How many litres of oxygen are needed to exactly react with 19.8 g of methane at STP? CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l)

Determine the volume of H₂S (at 375 K and 1.216 bar) needed to produce 55.0 g of S. Assume that there is excess SO₂ present. 2H₂S(g) + SO₂(g) → 3S(s) + 2H₂O(g)

Define the vapour pressure of water.

A syringe contains 589 mL of CO at 325 K and 1.2 bar. A second syringe contains 473 mL of N₂ at 298 K and 2.6 bar. What is the final pressure if the contents of these two syringes are injected into a 1.00 L container at STP?

A mixture of He, Ne, and Ar has a pressure of 7.85 bar. If the Ne has a mole fraction of 0.47 and Ar has a mole fraction of 0.23, what is the pressure of He?

The mole fraction of oxygen in dry air near sea level is 0.20948. The concentration of oxygen is ________ molecules per litre, assuming an atmospheric pressure of 0.985 bar and a temperature of 29.5 °C.

When 14.0 g of zinc metal reacts with excess HCl, how many litres of H₂ gas are produced at STP? Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

Determine the volume of O₂ (at STP) formed when 50.0 g of KClO₃ decomposes according to the following reaction. The molar mass for KClO₃is 122.55 g mol^-1. 2KClO₃(s) → 2KCl(s) + 3O₂(g)

Quiz 5: Gases

Identify the gas that is the lowest percent by volume in dry air.

A gas mixture contains CO, Ar, and H2. What is the total pressure of the mixture if the mole fraction of H2 is 0.35 and the pressure of H2 is 0.58 bar?

What pressure would a gas mixture in a 10.0 L tank exert if it were composed of 48.5 g He and 94.6 g CO2 at 398 K?

How many grams of zinc metal are required to produce 2.00 L of hydrogen gas at STP according to the chemical equation shown below? Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)

A gas mixture consists of N2, O2, and Ne, where the mole fraction of N2 is 0.55 and the mole fraction of Ne is 0.25. If the mixture is at STP in a 5.0 L container, how many molecules of O2 are present?

Define hypoxia.

A mixture of 10.0 g of Ne and 10.0 g Ar have a total pressure of 1.6 bar. What is the partial pressure of Ne?

A mixture of 0.220 moles CO, 0.350 moles H2, and 0.640 moles He has a total pressure of 2.989 bar. What is the pressure of H2?

In a container containing CO, H2, and O2, what is the mole fraction of CO if the H2 mole fraction is 0.22 and the O2 mole fraction is 0.58?

A mixture of N2, O2, and Ar has 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 bar?

A mixture of 0.220 moles CO, 0.350 moles H2, and 0.640 moles He has a total pressure of 2.95 bar. What is the pressure of CO?

How many litres of oxygen are needed to exactly react with 19.8 g of methane at STP? CH4(g) + 2O2(g) → CO2(g) + 2H2O(l)

Determine the volume of H2S (at 375 K and 1.216 bar) needed to produce 55.0 g of S. Assume that there is excess SO2 present. 2H2S(g) + SO2(g) → 3S(s) + 2H2O(g)

Define the vapour pressure of water.

A syringe contains 589 mL of CO at 325 K and 1.2 bar. A second syringe contains 473 mL of N2 at 298 K and 2.6 bar. What is the final pressure if the contents of these two syringes are injected into a 1.00 L container at STP?

A mixture of He, Ne, and Ar has a pressure of 7.85 bar. If the Ne has a mole fraction of 0.47 and Ar has a mole fraction of 0.23, what is the pressure of He?

The mole fraction of oxygen in dry air near sea level is 0.20948. The concentration of oxygen is ________ molecules per litre, assuming an atmospheric pressure of 0.985 bar and a temperature of 29.5 °C.

When 14.0 g of zinc metal reacts with excess HCl, how many litres of H2 gas are produced at STP? Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)

Determine the volume of O2 (at STP) formed when 50.0 g of KClO3 decomposes according to the following reaction. The molar mass for KClO3 is 122.55 g mol-1. 2KClO3(s) → 2KCl(s) + 3O2(g)

A gas mixture contains CO, Ar, and H₂. What is the total pressure of the mixture if the mole fraction of H₂ is 0.35 and the pressure of H₂ is 0.58 bar?

What pressure would a gas mixture in a 10.0 L tank exert if it were composed of 48.5 g He and 94.6 g CO₂ at 398 K?

How many grams of zinc metal are required to produce 2.00 L of hydrogen gas at STP according to the chemical equation shown below? Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

A gas mixture consists of N₂, O₂, and Ne, where the mole fraction of N₂ is 0.55 and the mole fraction of Ne is 0.25. If the mixture is at STP in a 5.0 L container, how many molecules of O₂ are present?

A mixture of 0.220 moles CO, 0.350 moles H₂, and 0.640 moles He has a total pressure of 2.989 bar. What is the pressure of H₂?

In a container containing CO, H₂, and O₂, what is the mole fraction of CO if the H₂ mole fraction is 0.22 and the O₂ mole fraction is 0.58?

A mixture of N₂, O₂, and Ar has 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 bar?

A mixture of 0.220 moles CO, 0.350 moles H₂, and 0.640 moles He has a total pressure of 2.95 bar. What is the pressure of CO?

How many litres of oxygen are needed to exactly react with 19.8 g of methane at STP? CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l)

Determine the volume of H₂S (at 375 K and 1.216 bar) needed to produce 55.0 g of S. Assume that there is excess SO₂ present. 2H₂S(g) + SO₂(g) → 3S(s) + 2H₂O(g)

A syringe contains 589 mL of CO at 325 K and 1.2 bar. A second syringe contains 473 mL of N₂ at 298 K and 2.6 bar. What is the final pressure if the contents of these two syringes are injected into a 1.00 L container at STP?

When 14.0 g of zinc metal reacts with excess HCl, how many litres of H₂ gas are produced at STP? Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

Determine the volume of O₂ (at STP) formed when 50.0 g of KClO₃ decomposes according to the following reaction. The molar mass for KClO₃is 122.55 g mol^-1. 2KClO₃(s) → 2KCl(s) + 3O₂(g)