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CHE 105/110 Introduction to Chemistry - Exercises and Answers

The Mole

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QUESTION ANSWER

1.

Express in mole terms what this chemical equation means.

CH4 + 2O2 → CO2 + 2H2O

 

1.

One mole of CH4 reacts with 2 mol of O2 to make 1 mol of CO2 and 2 mol of H2O.

3.

How many molecules of each substance are involved in the equation in Exercise 1 if it is interpreted in terms of moles?

 

3.

6.022 × 1023 molecules of CH4, 1.2044 × 1024 molecules of O2, 6.022 × 1023 molecules of CO2, and 1.2044 × 1024 molecules of H2O

5.

For the chemical equation

2C2H6 + 7O2 → 4CO2 + 6H2O
 

what equivalences can you write in terms of moles? Use the ⇔ sign.

5.

2 mol of C2H6 ⇔ 7 mol of O2 ⇔ 4 mol of CO2 ⇔ 6 mol of H2O

7.

Write the balanced chemical reaction for the combustion of C5H12 (the products are CO2 and H2O) and determine how many moles of H2O are formed when 5.8 mol of O2 are reacted.

7.

C5H12 + 8O2 → 5CO2 + 6H2O; 4.4 mol

9.

For the balanced chemical equation

3Cu(s) + 2NO3−(aq) + 8H+(aq) → 3Cu2+(aq) + 4H2O(ℓ) + 2NO(g)
 

how many moles of Cu2+ are formed when 55.7 mol of H+ are reacted?

9.

20.9 mol

11.

For the balanced chemical reaction

4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(ℓ)
 

how many moles of H2O are produced when 0.669 mol of NH3 react?

11.

1.00 mol

13.

For the balanced chemical reaction

4KO2(s) + 2CO2(g) → 2K2CO3(s) + 3O2(g)

determine the number of moles of both products formed when 6.88 mol of KO2 react.

13.

3.44 mol of K2CO3; 5.16 mol of O2

 

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