1. The law of conversation of matter states that in a chemical reaction, matter is neither created nor destroyed.
2. The scientific law summarizes what has been learned by careful observation of nature.
3. The terms "using up" and "throwing away" are misleading because according to the law of conservation of matter, matter is neither created nor destroyed, they are just changed.
4. a. Not balanced.
Reactant: Sn-1, H-1, F-1
Product: Sn-1, H-2, F-2
b. Not balanced.
Reactant: Si-1, O-2, C-1
Product: Si-1, O-1, C-2
c. Balanced
Reactant: Al-1, O-3, H-6, Cl-3
Product: Al-1, O-3, H-6, Cl-3
5. a. The coefficient for hydrogen gas: 3.
b. The coefficient for NH3 gas: 2.
c. The coefficient for nitrogen gas: 1.
6. a. 1 WO3 + 3 H2 --> 1 W + 3 H2O
7. a. 1 Ca3(PO4)2 + 3 H2SO4 --> 2 H3PO4 + 3 CaSO4
8. a. Yes, the atoms are conserved.
Reactant: Na-2, S-1, O-4, K-2, Cl-1
Product: Na-2, S-1, O-4, K-2, Cl-1
b. No, the student didnt create a properly balanced chemical equation because the subscripts are suppose to stay the same, and the coefficients are suppose to alter to balance the equation.
c. 1 Na2SO4 + 2 KCl --> 2 NaCl + 1 K2SO4
9. It would take 400,000 seconds to spend one mole of dollars if I could spend a billion dollars per second.
10. a. oxygen gas (O2): 32g
b. ozone (O3): 48g
c. limestone (CaCO3): 100g
d. a typical antacid Mg(OH)2: 58g
e. aspirin (C9H8O4): 180g
11. They can both correctly represent 1.00 mol of a substance because atomic mass equals atomic weight and the weight always stays the same.
12. a. 1 atom in 39.1g potassium
b. .5 atoms in 19.55g potassium
c. .1 atoms in 3.91g potassium
d. .03 atoms in 1.0g potassium
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