Unit 1 Sec. D Summary HW 3

7/9/14

7) a. The coefficient is 3

b. The coefficient is 2

c. The coefficient is 1

8) a. WO₃ + 3 H₂ –––> W + 3 H₂O

Reactants	Products
1 W atom	1 W atom
3 oxygen atoms	3 oxygen atoms
6 hydrogen atoms	6 hydrogen atoms

b. 2 PbS + 3 O₂ –––> 2 PbO + 2 SO₂

Reactants	Products
2 lead atoms	2 lead atoms
2 sulfur atoms	2 sulfur atoms
6 oxygen atoms	6 oxygen atoms

c. 4 Fe + 3 O₂ –––> 2 Fe₂O₃

Reactants	Products
4 iron atoms	4 iron atoms
6 oxygen atoms	6 oxygen atoms

9) a. Ca₃(PO₄)₂ + 3 H₂SO₄ –––> 2 H₃PO₄ + 3 CaSO₄

b. 2 C₈H₁₈ + 25 O₂ –––> 16 CO₂ + 18 H₂O

10) a. Yes

b. No, because the student put subscript 2 for the substance Na and K and those substances are not diatomic molecules so the student must put the 2 as a coefficient.

c. 2 NaSO₂ + 2 KCl –––> 2 NaCl + 2 KSO₂

11) An alloy is a solid solution consisting of atoms of two or more metals.

12) A plumbing fixture and brass are examples of alloys.