Chapter 4
Which of the following is not a redox reaction?
a. Photosynthesis
b. Breathalyzer tests
c. Corrosion
d. Acid-Base Reaction
d. Acid-Base Reaction
Which gas would you expect to have the largest b value in the van der Waals equation?
a. He
b. H2
c. O2
d. N2
e. Cl2
e. Cl2
If a gas occupies 3.60 liters at a pressure of 1.00 atm, what will be its volume at a pressure of 2.50 atm?
1.44L
Will the change in internal energy be negative, positive, 0, or cannot be determined if heat is going into the system and work is being done by the system?
Cannot be determined
A student mixes potassium nitrate (KNO₃) crystals with water in a beaker. After stirring for a few minutes, the temperature of the solution drops noticeably. Based on this observation, the dissolution of KNO₃ in water is an example of an ________.
a. Exothermic process
b. Endothermic process
a. Exothermic process
What are all of the oxidation numbers in H2CO3?
H: +1, C: +4, O: -2
Helium gas effuses through a room in 2.10 minutes. How long will it take for an equal amount of neon gas to effuse through a room under identical conditions?
4.72 minutes
What is the root mean square speed of a chlorine molecule at 28 oC?
325 m/s
A gas expands against a constant external pressure of 2.00 atm. The initial volume of the gas is 0.250 L and the final volume is 1.50 L. Calculate the work done by the gas (wgas) in Joules.
-253 J
A closed system loses 25J of heat to its surroundings and has 23J of work performed on it by the surroundings. What is ∆Esys?
-2J
Which of the following is a redox reaction? (Also explain why the others are not)
a. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
b. BaCl2(aq) + Na2SO4(aq) → BaSO4(s) + 2NaCl(aq)
c. Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(s)
d. AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
c. Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(s)
(a.) is an acid-base reaction
(b.) is a precipitation reaction
(d.) is a precipitation reaction
An ideal gas has a pressure of 515 Torr and occupies 645 mL at 38 oC. How many moles of gas does this correspond to?
0.0171 moles
A gas has a volume of 800.0 mL at 23.0 °C and 300.0 torr. What would the volume of the gas be at 227.0 °C and 500.0 torr of pressure?
811 mL
How much heat is required to convert 16.0 moles of liquid H2O at 23.5 °C into steam? The ΔHvap of water is 40.65 kJ/mol and the molar heat capacity of water in liquid form is 75.3 J/mol °C.
743 kJ
What is the enthalpy change for this reaction if the energy for H-H bonds is 436 kJ/mol, for I-I bonds it is 151 kJ/mol, and for H-I bonds it is 299 kJ/mol? Is the reaction endothermic or exothermic?
-11 kJ, Exothermic
Write the full half reactions for:
Zn + Cu2+ → Zn2+ + Cu
Zn → Zn2+ + 2e-
2e- + Cu2+ → Cu
What is the molar mass of a gas that has a density of 2.62 g/L at 2.00 atm and 25.0 °C?
32.1 g/mol
What is the density (in g/L) of propane (C3H8) gas at 25 oC and 651 torr?
1.54 g/L
Using the equations below
Cu(s) + ½O2(g) → CuO(s) ∆H = –156 kJ
2Cu(s) + ½O2(g) → Cu2O(s) ∆H = –170 kJ
What is the value of ∆H (in kJ) for the following reaction?
2CuO(s) → Cu2O(s) + ½O2(g)
142 kJ
Consider the reaction shown below. What is the standard molar enthalpy of formation of SO₂(g) if ΔH°f(SO₃(g)) = –396 kJ/mol?
2SO₂(g)+O₂(g) → 2SO₃(g) ΔH°rxn=−198 kJ
-297 kJ/mol
Balance the following redox reaction in acidic solution:
MnO4- + I- → I2 + Mn2+
16H+ + 2MnO4- + 10I- → 2Mn2+ + 8H2O + 5I2
Consider the following reaction:
4NO3(g) + 6H2O(g) 🡪 4NH3(g) + 9O2(g)
A 2.00 L vessel contains 3.00 atm of NO3(g) and 4.00 atm of H2O(g) at 375 oC. What will the partial pressure of NO3(g) if the reaction goes to completion? The volume and temperature are kept constant.
0.333 atm
2.00 atm of phosphorus pentachloride is injected into an evacuated 2.00 L vessel at 250. oC. This decomposes as shown below:
PCl5(g) → PCl3(g) + Cl2(g)
The total pressure in the vessel is measured to be 3.50 atm. Calculate the partial pressure of PCl5(g) after the reaction occurs.
0.50 atm
How much energy in kJ is needed to heat 5.00 g of ice from −10.0 °C to 30.0 °C? The heat of fusion of water is 6.01 kJ/mol, and the molar heat capacity is 37.6 J/mol °C for ice and 75.3 J/mol °C for liquid water. The melting point for water is at 0 °C and the boiling point is at 100 °C.
2.41 kJ
A 150.0 g piece of an unknown metal is heated to 95.0 °C and then quickly placed into 100.0 g of water at 25.0 °C inside a coffee-cup calorimeter. The specific heat capacity of water is 4.18 J/g °C. Assume that no heat is absorbed by the calorimeter itself, and that the final equilibrium temperature of the system is measured to be 29.5 °C. Calculate the specific heat capacity of the metal.
0.191 J/g °C