Q: Which of the following represents the correct complete ionic equation when aqueous solutions of Na2SO3 and HCl are mixed?

$$2 \text{Na}^+(aq) + \text{SO}_3$$^{2-}$$(aq) + 2 \text{H}^+(aq) + 2 \text{Cl}^-(aq) \rightarrow \text{H}_2\text{O}(l) + \text{SO}_2(g) + 2 \text{Na}^+(aq) + 2 \text{Cl}^-(aq)$$

Q: Indicate the balanced net ionic equation for the reaction: $$\text{NH}_4\text{Br} (aq) + \text{KOH} (aq) \rightarrow \text{H}_2\text{O} (l) + \text{NH}_3 (g) + \text{KBr} (aq)$$

$$\text{NH}_4^+ (aq) + \text{OH}^- (aq) \rightarrow \text{H}_2\text{O} (l) + \text{NH}_3 (g)$$

Question 1

What is the coefficient on ammonia in the balanced equation for the reaction of gaseous ammonia (NH3) with gaseous oxygen to form gaseous nitrogen monoxide and gaseous water?

Accepted Answer

2

Question 2

Which of the following represents the correct complete ionic equation when aqueous solutions of Na2SO3 and HCl are mixed?

Accepted Answer

$$2 	ext{Na}^+(aq) + 	ext{SO}_3$$^{2-}$$(aq) + 2 	ext{H}^+(aq) + 2 	ext{Cl}^-(aq) ightarrow 	ext{H}_2	ext{O}(l) + 	ext{SO}_2(g) + 2 	ext{Na}^+(aq) + 2 	ext{Cl}^-(aq)$$

Question 3

What kind of reaction occurs when aqueous bromic acid is mixed with calcium hydroxide?

Accepted Answer

Acid-base neutralization

Question 4

Indicate the balanced net ionic equation for the reaction: $$	ext{NH}_4	ext{Br} (aq) + 	ext{KOH} (aq) ightarrow 	ext{H}_2	ext{O} (l) + 	ext{NH}_3 (g) + 	ext{KBr} (aq)$$

Accepted Answer

$$	ext{NH}_4^+ (aq) + 	ext{OH}^- (aq) ightarrow 	ext{H}_2	ext{O} (l) + 	ext{NH}_3 (g)$$

Question 5

A 25.00 mL sample of $$	ext{H}_2	ext{SO}_4$$ requires 30.55 mL of 0.5510 M NaOH for its titration. What was the concentration of the $$	ext{H}_2	ext{SO}_4$$? (Balanced: $$	ext{H}_2	ext{SO}_4 + 2	ext{NaOH} ightarrow 2	ext{H}_2	ext{O} + 	ext{Na}_2	ext{SO}_4)$$

Accepted Answer

0.2496 M

Question 6

What volume of a 0.5500 M solution of AgNO3 is needed to completely react with 100.0 mL of a 0.2500 M solution of CaCl2 in the reaction: $$2 	ext{AgNO}_3(aq) + 	ext{CaCl}_2(aq) ightarrow 2 	ext{AgCl}(s) + 	ext{Ca(NO}_3)_2(aq)$$?

Accepted Answer

166.7 mL

Question 7

A system releases 587 kJ of heat and does 115 kJ of work on the surroundings. What is the change in internal energy of the system?

Accepted Answer

$$\Delta E = -472 	ext{ kJ}$$

Question 8

A 11.6-g sample of silicon at 86.0 $$^\circC is $$immersed into 26.0 g of water at 24.0 $$^\circC. $$What is the final temperature at thermal equilibrium? ($$C_{s,	ext{Si}} = 0.790 	ext{ J/g} \cdot ^\circ	ext{C}$$, $$C_{s,	ext{H}_2$$	ext{O}} = 4.18 	ext{ J/g} \cdot ^\circ	ext{C}$$)

Accepted Answer

38.7 $$^\circC$$

Question 9

Propane ($$	ext{C}_3	ext{H}_8) $$has a normal boiling point of 231.2 K and a heat of vaporization of 19.04 kJ/mol. What is the vapor pressure of propane at 298.2 K? (Use $$\ln \frac{P_2$}{P_1$} = -\frac{\Delta H_{vap}}{R} (\frac{1}{T_2$} - \frac{1}{T_1$})$$ and $$P_1 = 760$ torr at T_1$)

Accepted Answer

9040 torr

Question 10

Solid CO2 "disappears" after sitting at room temperature for a while, leaving no puddle. What happened?

Accepted Answer

The solid CO2 sublimed.

Question 11

Use the bond energies provided to estimate $$\Delta H^\circ_{rxn}$$ for the reaction: $$2 	ext{CH}_3	ext{OH} (l) + 3 	ext{O}_2 (g) ightarrow 2 	ext{CO}_2 (g) + 4 	ext{H}_2	ext{O} (g). (C-H$$: 414 kJ/mol, C-O: 360 kJ/mol, C=O: 799 kJ/mol, O=O: 498 kJ/mol, O-H: 464 kJ/mol)

Accepted Answer

$$-1282 kJ$$

Question 12

The combustion of ethene occurs via the reaction: $$	ext{C}_2	ext{H}_4 (g) + 3 	ext{O}_2 (g) ightarrow 2 	ext{CO}_2 (g) + 2 	ext{H}_2	ext{O} (g). $$Using the provided heats of formation, calculate the enthalpy for the combustion of 1 mole of ethene.

Accepted Answer

$$-1411 kJ$$

Question 13

Under what conditions is the change in enthalpy, $$\Delta H_{rxn}$$, equal to the heat evolved in a chemical reaction?

Accepted Answer

constant pressure

Question 14

Refer to the phase diagram provided. The transition shown by the line from C to E is:

Accepted Answer

sublimation

Question 15

Refer to the phase diagram provided. The line that runs from point A to point B is known as the:

Accepted Answer

vaporization curve

Question 16

A 25.00 mL sample of $$	ext{H}_2	ext{SO}_4 is $$titrated with 30.55 mL of 0.5510 M NaOH. What is the number of moles of NaOH used?

Accepted Answer

$$0.0168$$ mol

Question 17

Which of the following best describes the process occurring when a substance moves directly from the solid phase to the gas phase?

Accepted Answer

Sublimation

Question 18

Given the reaction $$2	ext{S}(s) + 3	ext{O}_2(g) + 4	ext{KOH}(aq) ightarrow 2	ext{K}_2	ext{SO}_4(aq) + 2	ext{H}_2	ext{O}(l)$$, if you start with 4.0 g S, 3.0 g O2, and 8.0 g KOH, which is the limiting reactant?

Accepted Answer

O2(g)

Question 19

A cylinder with a moving piston expands from an initial volume of 0.150 L against an external pressure of 1.70 atm. The expansion does 296 J of work on the surroundings. What is the final volume of the cylinder? ($$w = -P\Delta V$$; $$1	ext{ L} \cdot 	ext{atm} = 101.3 	ext{ J})$$

Accepted Answer

1.87 L

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