Chemistry Answers

When one mole of nitrogen gas, N2, reacts with one mole of oxygen gas, O2, two moles of nitric

oxide, NO, are formed. In the process, 180.5 kJ of heat are required.

a. Write the thermochemical equation for the chemical reaction (Use two ways in writing the

equation)

b. What does the sign of ΔH indicate?

c. Is the reaction endothermic or exothermic? what happens to heat when the reaction takes

place?

d. If 3 moles of nitrogen gas, N2, are made to react with three moles of oxygen gas, O2, how

much heat is required in the process?

e. How much heat will be released if two moles of nitric oxide, NO, are broken down into one

mole of nitrogen gas, N2, and one mole of oxygen gas, O2?

Consider an acid-base reaction when Nitric acid is added to copper (11) hydroxide. What is the net ironic equation for this reaction

One mole nitrogen oxide, NO, reacts with oxygen gas to produce a brown gas. How many moles NO must react with excess oxygen to release 120kJ of

heat?

One mole nitrogen oxide reacts with oxygen gas to produce a brown gas. Calculate thermochemical equation if 20g of NO completely reacted

Propane, C₃H₈, is a fuel commonly used for cooking on gas grills and for heating in rural areas where natural gas is unavailable. Propane reacts with oxygen gas to produce heat and the products carbon dioxide and water. This combustion reaction is represented by the unbalanced equation

C₃H₈(g) + O₂(g) → CO₂(g) + H₂O(g)

Give the balanced equation for this reaction, and state the meaning of the equation in terms of numbers of molecules and moles of molecules.

8. Calculate the missing cell potential. 2.20 V 0.77 V -0.44

FeO4

2- Fe

3+ Fe

2+ Fe

E

o Will Fe

3+ disproportionate. Give reasons.

7. Consider the following half-reactions:

Half-Reaction E0 (V)  MnO4(aq) + 8 H+ + 5 e

- Mn

2+ + 4 H2O +1.52

2 C 2O7(aq) r + 14 H+ + 6 e

- Cr

3+ + 7 H2O +1.33  B 3(aq) rO + 6 H+ + 6 e

- 𝐵− + 3 H2O +1.47

2 SO4(aq) + 4 H+ + 2 e

- SO2(g) + 2 H2O +0.2  NO3(aq) + 4 H+ + 3 e

- NO(g) + 2 H2O + 0.96

(a) Identify the strongest oxidizing agent and the strongest reducing agent. (b) Which of the oxidizing agents listed is / are capable of oxidizing 𝐵−

to  B 3(aq) rO in acidic solution. (c) Write a balanced chemical equation for the reaction of 2 C 2O7(aq) r and

SO2(g) in acid medium. Is this reaction spontaneous?

(d) Write a balanced chemical equation for the reaction of 2 C 2O7(aq) r with

Mn

2+

(aq) in acid medium. Is this reaction spontaneous?

3. Calculate the maximum work available from 50.0 g of aluminum in the following

cell when the cell potential is 1.15 V. Al(s) |Al3+

(aq) || H+

(aq) | O2(g) |Pt . Note that O2 is reduced to H2O. Use appropriate standard reduction potentials

13. Consider the lead acid battery. a) What class of battery is it and what distinguishes it from the other

classes of batteries?

b) Give the cell notation for the lead acid battery. c) Write the half reactions and the discharging reaction of the battery. d) If each cell in the battery has an output of approximately two volts, draw a labelled sketch diagram of a battery with a six volt output. On

the diagram indicate the anode and the cathode. Name one characteristic of an ideal lead-acid battery.