Question

1. a 2 l container will hold about 4 g of which of the following gases at 0°c and 1 atm?

(a) n₂
(b) so₂
(c) nh₃
(d) co₂

1. when the actual gas volume is greater than the volume predicted by the ideal gas law, the explanation lies in the fact that the ideal gas law does not include a factor for molecular.

(a) volume
(b) mass
(c) attractions
(d) shape

1. which of the following lewis diagrams represents the substance that would exhibit the most significant hydrogen bonding in a pure liquid sample?

(a)
h h h h h
h - c - c - c - c - h
h h h h h
(b)
h h h h
h - c - c - o - c - c - h
h h h h
(c)
h h h
h - c - c - c - n - h
h h h h
(d)
h :o: h
h - c - c - c - h
h h

1. which element, ar or kr, has the lower boiling point, and why?

(a) ar, because it has a smaller, less polarizable electron cloud than kr
(b) ar, because its atoms have a faster average speed at a given temperature than kr atoms
(c) kr, because it has a larger, more polarizable electron cloud than ar
(d) kr, because its atoms have a slower average speed at a given temperature than ar atoms

1. a gas mixture at 0°c and 1.0 atm contains 0.010 mol of h₂, 0.015 mol of o₂, and 0.025 mol of n₂. assuming ideal behavior, what is the partial pressure of hydrogen gas (h₂) in the mixture?

(a) about 0.010 atm, because there is 0.010 mol of h₂ in the sample.
(b) about 0.050 atm, because there is 0.050 mol of gases at 0°c and 1 atm.
(c) about 0.020 atm, because h₂ comprises 20% of the total number of moles of gas.
(d) about 0.400 atm, because the mole ratio of h₂: o₂: n₂ is 0.4: 0.6: 1.

Explanation:

Question 1

Step1: Use ideal gas law \(PV = nRT\)

At \(T=273\ K\), \(P = 1\ atm\), \(V=2\ L\), \(R = 0.0821\ L\cdot atm/(mol\cdot K)\). Rearranging \(n=\frac{PV}{RT}\), we get \(n=\frac{1\times2}{0.0821\times273}\approx0.089\ mol\).

Step2: Calculate molar mass \(M=\frac{m}{n}\)

Given \(m = 4\ g\), \(M=\frac{4}{0.089}\approx45\ g/mol\).

• For \(N_2\), \(M = 28\ g/mol\)
• For \(SO_2\), \(M=64\ g/mol\)
• For \(NH_3\), \(M = 17\ g/mol\)
• For \(CO_2\), \(M=44\ g/mol\approx45\ g/mol\)

The ideal gas law assumes no molecular interactions. When actual volume is greater than ideal - predicted volume, it's because the ideal gas law doesn't account for molecular attractions. Molecular attractions pull gas molecules together, but if the volume is larger than ideal (assuming non - zero volume of molecules is already considered in some corrections), the lack of accounting for attractions (which would make the gas more "compact" if they were considered in a more refined model) can lead to this discrepancy.

Hydrogen bonding occurs when \(H\) is bonded to \(N\), \(O\), or \(F\).

• Option a) has no \(N\), \(O\), or \(F\)
• Option b) has an \(O\) atom, but no \(H - O\) bond (it's an ether - like structure)
• Option c) has an \(N - H\) bond. Hydrogen bonding is significant in substances with \(N - H\), \(O - H\), or \(F - H\) bonds.
• Option d) has an \(O\) atom, but no \(H - O\) bond (it's a ketone - like structure)

Answer:

d) \(CO_2\)

Question 2