Question 1

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) 0.20 B) 0.30 C) 0.10 D) 0.50

Accepted Answer

The sum of mole fractions in a mixture is always 1. Given H₂ is 0.22 and O₂ is 0.58, CO is 1 - (0.22 + 0.58) = 0.20.

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? A) 1.7 bar B) 0.20 bar C) 0.49 bar D) 0.60 bar E) 2.1 bar

Accepted Answer

The total pressure of the mixture is the sum of the partial pressures of each gas. The partial pressure of a gas is the pressure it would exert if it occupied the entire volume alone. The mole fraction of a gas is the ratio of the number of moles of that gas to the total number of moles of all gases in the mixture. The partial pressure of a gas is equal to the mole fraction of that gas multiplied by the total pressure of the mixture.In this case, the mole fraction of H₂ is 0.35 and the pressure of H₂ is 0.58 bar. Therefore, the partial pressure of H₂ is 0.35 * 0.58 bar = 0.20 bar. The total pressure of the mixture is the sum of the partial pressures of CO, Ar, and H₂. Therefore, the total pressure of the mixture is 0.20 bar + 0.20 bar + 0.58 bar = 1.7 bar.

Question 3

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? A) 1.86 bar B) 0.649 bar C) 0.536 bar D) 1.54 bar E) 0.955 bar

Accepted Answer

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

Question 4

Define the vapour pressure of water.
A) partial pressure of water in a liquid mixture
B) partial pressure of water in a gaseous mixture
C) condensation of water
D) water dissolved in a liquid
E) water molecules

Accepted Answer

Vapour pressure of water refers to the partial pressure of water in a gaseous mixture. It is the pressure exerted by water vapour in equilibrium with its liquid or solid form at a particular temperature. It is affected by factors such as temperature, atmospheric pressure, and the presence of other gases in the mixture.

Question 5

What volume will 4.91 × 10²²atoms of Ne occupy at STP? A) 1.10 L B) 2.00 L C) 2.24 L D) 3.11 L E) 1.85 L

Accepted Answer

The answer of What volume will 4.91 × 10²²atoms...

Question 6

A compound is found to be 30.45% N and 69.55 % O by mass. If 1.63 g of this compound occupy 389 mL at 0.00 °C and 1.0332 bar, what is the molecular formula of the compound? A) NO₂ B) N₂O C) N₄O₂ D) N₂O₅ E) N₂O₄

Accepted Answer

1) We can first find the mass percentage of each element present in the compound: - Mass percentage of N = (30.45 g N / 100 g compound) = 0.3045 - Mass percentage of O = (69.55 g O / 100 g compound) = 0.6955 2) Next, we can calculate the number of moles of each element present in 1.63 g of the compound: - Moles of N = (0.3045)(1.63 g) / 14.01 g/mol = 0.0354 - Moles of O = (0.6955)(1.63 g) / 16.00 g/mol = 0.0718 3) We can then find the mole ratio of N to O: - Divide both mole values by the smaller value (0.0354): - N:O mole ratio ≈ 1:2 (rounded to nearest whole number) 4) We can use this ratio to write a tentative empirical formula: - Empirical formula: N1O2 5) Finally, we can use the molar mass of the empirical formula to see if we need to multiply by a whole number to get the actual molecular formula. The molar mass of the empirical formula is: - (1)(14.01 g/mol) + (2)(16.00 g/mol) = 46.01 g/mol - The actual molecular mass (found from the mass of 1.63 g and the density of the compound) is approximately 46.5 g/mol. - Since these two masses are close, we don't need to multiply the empirical formula by anything, and the molecular formula is the same as the empirical formula: - Molecular formula: N1O2₄

Question 7

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? A) 7.11 bar B) 39.6 bar C) 40.1 bar D) 47.2 bar E) 58.7 bar

Accepted Answer

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

Question 8

Determine the density of  gas at 278 K and 1.00 bar.
A) 1.14 g 
B) 2.37 g 
C) 1.90 g 
D) 3.08 g 
E) 2.11 g

Accepted Answer

The answer of Determine the density of  gas at...

Question 9

Identify the gas that is the lowest percent by volume in dry air. A) CO₂ B) Ar C) O₂ D) N₂

Accepted Answer

Carbon dioxide (CO2) is present in the smallest percentage by volume in dry air compared to argon (Ar), oxygen (O2), and nitrogen (N2).

Question 10

Define hypoxia.
A) oxygen starvation
B) increased oxygen concentration in body tissues
C) increased nitrogen concentration in body tissues and fluids
D) nitrogen starvation

Accepted Answer

Hypoxia is the condition in which body tissues are oxygen-starved. This can lead to a variety of issues such as cell damage or death, organ failure, and even death.

Question 11

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) 4.5 × 10²²molecules O₂ B) 2.7 × 10²² molecules O₂ C) 3.7 × 10²³ molecules O₂ D) 1.1 × 10²³ molecules O₂ E) 9.3 × 10²⁴ molecules O₂

Accepted Answer

First, we can find the mole fraction of O₂: Mole fraction of N₂ + Mole fraction of O₂ + Mole fraction of Ne = 1 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 = PV/RT At STP, P = 1 atm and T = 273 K So n = (1 atm)(5.0 L)/(0.0821 L•atm/mol•K)(273 K) = 0.204 mol Using Avogadro's number, we can convert this to the number of molecules: (0.204 mol)(6.02 x 10^23 molecules/mol) = 1.23 x 10^23 molecules Finally, we can find the number of molecules of O₂: (0.20)(1.23 x 10^23 molecules) = 2.46 x 10^22 molecules Therefore, the answer is B, 2.7 x 10^22 molecules O₂.

Question 12

A 0.334 g sample of an unknown halogen occupies 109 mL at 398 K and 1.43 bar. What is the identity of the halogen? A) Br₂ B) F₂ C) Cl₂ D) I₂ E) At₂

Accepted Answer

The answer of A 0.334 g sample of an unknown...

Question 13

What volume will 0.780 moles of He occupy at STP?
A) 22.4 L
B) 70.0 L
C) 43.7 L
D) 17.7 L
E) 15.6 L

Accepted Answer

The answer of What volume will 0.780 moles of He...

Question 14

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) 1.1 bar
B) 0.80 bar
C) 0.54 bar
D) 0.40 bar
E) 1.3 bar

Accepted Answer

Dalton's law of partial pressures states that the total pressure exerted by a mixture of non-reacting gases is equal to the sum of the partial pressures of each individual gas. The partial pressure of a gas is the pressure that the gas would exert if it occupied the entire volume alone. In this case, the total pressure is 1.6 bar, and the mixture contains 10.0 g of Ne and 10.0 g of Ar. The molar mass of Ne is 20.18 g/mol, and the molar mass of Ar is 39.95 g/mol. Therefore, the number of moles of Ne in the mixture is 10.0 g / 20.18 g/mol = 0.496 mol, and the number of moles of Ar in the mixture is 10.0 g / 39.95 g/mol = 0.250 mol. The partial pressure of Ne is then:P(Ne) = X(Ne) * P(total)P(Ne) = 0.496 mol / (0.496 mol + 0.250 mol) * 1.6 barP(Ne) = 1.1 barTherefore, the correct answer is A.

Question 15

A 0.465 g sample of an unknown compound occupies 245 mL at 298 K and 1.24 bar. What is the molar mass of the unknown compound?
A) 26.3 g 
B) 33.9 g 
C) 12.2 g 
D) 37.9 g 
E) 81.8 g

Accepted Answer

The answer of A 0.465 g sample of an unknown...

Question 16

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?
A) 4.2 bar
B) 3.7 bar
C) 1.8 bar
D) 5.5 bar
E) 2.4 bar

Accepted Answer

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

Question 17

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) 2.5 bar B) 0.39 bar C) 0.67 bar D) 0.98 bar E) 1.33 bar

Accepted Answer

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

Question 18

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 273 K? A) 0.59 bar B) 1.1 bar C) 1.7 bar D) 1.9 bar E) 3.8 bar

Accepted Answer

First, we need to calculate the number of moles of CO and N₂ using the ideal gas law: $n = \frac{PV}{RT}$ For CO: $n_{CO} = \frac{(1.2\ bar)(0.589\ L)}{(0.0831\ L\cdot bar/mol\cdot K)(325\ K)} = 0.028\ mol$ For N₂: $n_{N₂} = \frac{(2.6\ bar)(0.473\ L)}{(0.0831\ L\cdot bar/mol\cdot K)(298\ K)} = 0.058\ mol$ Next, we need to calculate the total number of moles and the total volume of the gases when they are mixed together: $n_{total} = n_{CO} + n_{N₂} = 0.028\ mol + 0.058\ mol = 0.086\ mol$ $V_{total} = 0.589\ L + 0.473\ L + 1.00\ L = 2.062\ L$ Then, we can use the ideal gas law again to calculate the final pressure: $P_{final} = \frac{n_{total}RT}{V_{total}} = \frac{(0.086\ mol)(0.0831\ L\cdot bar/mol\cdot K)(273\ K)}{2.062\ L} = 1.7\ bar$ Therefore, the final pressure is 1.7 bar, which is choice C.

Question 19

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 A) 0.0196 g H₂ B) 0.0717 g H₂ C) 0.0190 g H₂ D) 0.0144 g H₂ E) 0.0449 g H₂

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 20

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? A) 1.17 bar B) 0.865 bar C) 1.03 bar D) 0.969 bar E) 0.649 bar

Accepted Answer

The pressure of H₂ can be found using the mole fraction and total pressure: (0.350 moles H₂ / (0.220 + 0.350 + 0.640) moles total) * 2.989 bar = 0.865 bar.

Quiz 5: Gases

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 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?

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?

Define the vapour pressure of water.

What volume will 4.91 × 1022 atoms of Ne occupy at STP?

A compound is found to be 30.45% N and 69.55 % O by mass. If 1.63 g of this compound occupy 389 mL at 0.00 °C and 1.0332 bar, what is the molecular formula of the compound?

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?

Determine the density of gas at 278 K and 1.00 bar.

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

Define hypoxia.

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 0.334 g sample of an unknown halogen occupies 109 mL at 398 K and 1.43 bar. What is the identity of the halogen?

What volume will 0.780 moles of He occupy at STP?

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 0.465 g sample of an unknown compound occupies 245 mL at 298 K and 1.24 bar. What is the molar mass of the unknown compound?

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?

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 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 273 K?

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 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?

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?

What volume will 4.91 × 10²²atoms of Ne occupy at STP?

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?

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 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 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 273 K?

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?