GENERAL CHEMISTRY
Calculations Based on Equations
Sheet No. 2
1.
How many atoms of Na are there in 69g of Na?
2.
How many grams will 3.01  1024 molecules of H2SO4 weigh?
3.
How many atoms are there in 294g of H2SO4?
4.
How many moles of H2SO4 are present in a sample which weighs 294g?
5.
How many grams H2SO4 are present in .7 moles?
6.
What is the percent of oxygen in MgO?
7.
How many grams of Mg are present in 800g of MgO?
8.
What is the percent of oxygen in Na2O2?
9.
What weight of oxygen is contained in 40g of KClO3?
10.
What weight of Fe2O3 will contain 100g of oxygen?
11.
What weight of MgO will contain 128.0 g of oxygen?
12.
What weight of oxygen will be formed by the decomposition of 80g of mercury (II) oxide?
HgO
Hg + O2.
13.
Iron ore contains 40% iron. How many grams of hydrogen are produced from 160 grams of the
ore according to the equation Fe + HCl
FeCl3 + H2
14.
A solution containing 50.0g of NaOH is mixed with one containing 50.0g of HCl. Given
NaOH + HCl
NaCl + H2O which chemical is in excess and what weight of NaCl is
produced?
15.
What weight in grams of silver chloride will be formed when 35.4g of NaCl and 99.8g of AgNO3
are mixed in water solution?
16.
How many grams of lead will be obtained from 2000 grams of ore containing 21.0% PbS, the yield
of lead being 94% of the theoretical amount? PbS + O 2
Pb + SO2
17.
What weight of sulfur which is 98% pure would be required in the production of 75.0 kilograms of
H2SO4 if each atom of sulfur is converted into one molecule of H2SO4 ?
18.
Determine the empirical formula for the following:
1.
2.
3.
4.
A compound containing 5.9% H and 94.1% O.
A compound containing 75% C and 25% H.
A compound containing 69.9% Fe and the remainder is O.
A compound containing 28.2% N, 8.1% H, 20.8% P, and 42.9%O. (It is known to
contain the (NH4) radical. Write your formula accordingly.)
ANSWERS
Calculations Based on Equations
Sheet No. 2
1.
1.806  1024 atoms
2.
490 grams
3.
1.264  1025 atoms
4.
3 moles
5.
68.6 grams
6.
40 percent
7.
480 grams
8.
41 percent
9.
15.66 grams
10.
332.5 grams
11.
320 grams
12.
5.93 grams
13.
3.43 grams
14.
HCl is in excess by 4.37 grams
73.12g of NaCl
15.
84.24 grams
16.
341.94 grams
17.
25 kg
18.
(1) HO
(2) CH4
(3) Fe2O3
(4) (NH4)3 PO4