The mole is the unit for amount of substance. The number of particles in a substance can be found using the Avogadro constant. The mass of product depends upon the mass of limiting reactant.

What is the mass of 5 moles of carbon? (A_{r} of Carbon = 12)

2.4 g

12 g

60 g

How many moles water (H_{2}O) are in 90 g of water? (A_{r} of Hydrogen = 1, A_{r} of O = 16)

18

5

0.2

How many moles are in 2 g of solid sodium hydroxide (NaOH)? (A_{r} of Na = 23, A_{r} of O = 16, Ar of H = 1).

0.05

0.07

80

How many molecules are there in 0.25 moles of methane, CH_{4}? (Assume Avogadro's Constant is 6 x 10^{23}).

1.5 x 10^{23}

2.4 x 10^{24}

1.5

How many atoms are there in 3.4 g of ammonia (NH_{3})? (A_{r} of N = 14, A_{r} of H = 1). Assume Avogadro's constant is 6 x 10^{23}.

1.2 x 10^{23}

4.8 x 10^{23}

How many oxygen atoms are in 1.1 g of carbon dioxide, CO_{2}? (A_{r} of C = 12 , A_{r} of O = 16). Assume Avogadro's constant is 6 x 10^{23}.

1.5 x 10^{22}

3 x 10^{22}

4.5 x 10^{23}

How many ions are contained in 9.4g of potassium oxide, K_{2}O? (A_{r} of K = 39, A_{r} of O = 16). Assume Avogadro's constant is 6 x 10^{23}.

6 x 10^{22}

1.8 x 10^{24}

1.8 x 10^{23}

What is the reactant that is completely used up in a chemical reaction called?

Excess reactant

Limiting reactant

Limiting product

What mass of hydrogen is produced when 36 g of magnesium reacts completely with excess sulfuric acid? (A_{r} of Mg = 24; M_{r} of H_{2} = 2)

The balanced equation is: Mg(s) + H_{2}SO_{4}(aq) → MgSO_{4}(aq) + H_{2}(g).

3 g

2 g

1 g

If 1.6 g of sulfur combines with 2.4 g of oxygen, how many moles of oxygen will combine with 1 mole of sulfur? (A_{r} of S is 32; A_{r} of O is 16)

1

3