1. What is the mass of one mole of ammonium hydroxide, NH₄OH?  (N = 14; H = 1; O = 16)

2. What is the mass of 1.5 moles of sodium sulphate Na₂SO₄? (Na = 23; S = 32; O = 16)

3.  How many moles are there in 1.4 g lithium bromide, LiBr (Li = 7;  Br = 80)

4. (Harder) In an experiment, hydrochloric acid is added to calcium carbonate.  They react to give calcium chloride, carbon dioxide, and water.  2.0 g calcium carbonate was used and reacted completely.  The change in mass is measured.

(a)  Write a balanced equation for the reaction.

(b) How much carbon dioxide is given off?

(c) Does the water made in the reaction affect the loss in mass?

(Relative atomic masses:  Ca = 40; C = 12; O =16; Cl = 35.5; H = 1)

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