Section C Summary: 1-12

1.    The law of conservation of matter states that in a chemical reaction matter is neither created nor destroyed.

2.    A scientific law summarizes what has been learned by careful observation of nature.

3.    The expressions “using up” and “throwing away” are misleading because matter is never destroyed. Instead, matter is changed into new substances chemically, like a gas.

4.    Atom inventories:

a. Reactant side: Sn=1, H=1, F=1

   Product side: Sn=1, H=2, F=2

   This is an unbalanced equation.

b. Reactant side: Si=1, O=2, C=1

   Product side: Si=1, C=2, O=1

  This is an unbalanced equation.

c. Reactant side: Al=1, O=3, H=6, Cl=3

  Product side: Al=1, O=3, H=6, Cl=3

  This is a balanced equation

5.    Coefficients:

a.    3

b.    2

c.    1

6.    On paper

7.    Balancing equations:

a.    1 Ca3(PO4)2 + 3 H2SO4 à 2 H3PO4 + 3 CaSO4

b.    2 C8H18 + 25 O2 à 16 CO2 + 18 H2O

8.    More balancing:

a.    Reactant: Na=2, S=1, O=4, K=2, Cl=1; Product: Na=2, S=1, O=4, K=2, Cl=1

b.    No they did not, because they added subscripts to the equations, which does not create a correctly balanced equation.

c.    Na2SO4 + 2 KCl à 2 NaCl + K2SO4

9.     

10. Molar Nass:

a.    32 g

b.    48 g

c.    100 g

d.    58 g

e.    224 g

11.They each equal 1.00 mol of substance because their atoms don’t weigh the same or take up the same amount of density. One mol is going to be different for each substance.

12.