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Unit – 4 Moles and Stoichiometry Page 1 of 2
Mole to Grams, Grams to Moles Conversions Worksheet
What are the molecular weights of the following compounds?
1) NaOH 2) H
3
PO
4
3) H
2
O 4) Mn
2
Se
7
5) MgCl
2
6) (NH
4
)
2
SO
4
There are three definitions (equalities) of mole. They are:
1 mole = 6.02 x 10
23
particles
1 mole = molar mass (could be atomic mass from periodic table or molecular mass)
1 mole = 22.4 L of a gas at STP (You do not need to worry about this yet)
Each definition can be written as a set of two conversion factors. They are:
1 mole = molar mass(g) can be written as ____1 mole OR _molar mass (g)
molar mass (g) 1 mole
1 mole = 6.02 x 10
23
particles can be written as ____1 mole OR __6.02 x 10
23
_
6.02 x 10
23
1 mole
Solve of the following:
1) How many moles are in 15 grams of lithium?
2) How many grams are in 2.4 moles of sulfur?
3) How many moles are in 22 grams of argon?
4) How many grams are in 88.1 moles of magnesium?
5) How many moles are in 2.3 grams of phosphorus?
To find moles divide molar mass To find grams multiply molarmass
Unit – 4 Moles and Stoichiometry
6) How many grams are in 11.9 moles of chromium?
7) How many moles are in 9.8 grams of calcium?
8) How many grams are in 238 moles of arsenic?
Solve he following:
9) How many grams are in 4.5 moles of sodium fluoride, NaF?
10) How many moles are in 98.3 grams of aluminum hydroxide, Al(OH)
3
?
11) How many grams are in 0.02 moles of beryllium iodide, BeI
2
?
12) How many moles are in 68 grams of copper (II) hydroxide, Cu(OH)
2
?
13) How many grams are in 3.3 moles of potassium sulfide, K
2
S?
14) How many moles are in 1.2 x 10
3
grams of ammonia, NH
3
?
15) How many grams are in 2.3 x 10
-4
moles of calcium phosphate, Ca
3
(PO
3
)
2
?
16) How many moles are in 3.4 x 10
-7
grams of silicon dioxide, SiO
2
?
17) How many grams are in 1.11 moles of manganese sulfate, Mn
3
(SO
4
)
7
?
Page 2 of 2
Unit – 4 Moles and Stoichiometry
Mole Calculation Worksheet – Answer Key
What are the molecular weights of the following compounds?
1) NaOH 23 + 16 + 1 = 40.1 grams 2) H
3
PO
4
3 + 31 + 64 = 98.0 grams
3) H
2
O 2 + 16 = 18.0 grams 4) Mn
2
Se
7
663.0 grams
5) MgCl
2
95.3 grams 6) (NH
4
)
2
SO
4
132.1 grams
Solve any 15 of the following:
1) How many moles are in 15 grams of lithium? 15/7 = 2.14 moles
2) How many grams are in 2.4 moles of sulfur? 2.4 x 32 = 76.8 grams
3) How many moles are in 22 grams of argon? 22/40 = 0.55 moles
4) How many grams are in 88.1 moles of magnesium? 88.1 x 24 = 2114.4 grams
5) How many moles are in 2.3 grams of phosphorus? 2.3/31 = 0.074 moles
6) How many grams are in 11.9 moles of chromium? 11.9 x 52 = 618.8 grams
7) How many moles are in 9.8 grams of calcium? 9.8/40 = 0.25 moles
8) How many grams are in 238 moles of arsenic? 238 x 75 = 17,850 grams
9) How many grams are in 4.5 moles of sodium fluoride, NaF? 4.5 x 42 = 189 grams
10) How many moles are in 98.3 grams of aluminum hydroxide, Al(OH)
3
? 98.3/78 = 1.26 moles
11) How many grams are in 0.02 moles of beryllium iodide, BeI
2
? 0.02 x 263 = 5.26 grams
12) How many moles are in 68 grams of copper (II) hydroxide, Cu(OH)
2
? 68/99 = 0.69 moles
13) How many grams are in 3.3 moles of potassium sulfide, K
2
S? 3.3 x 110 = 363.0 grams
14) How many moles are in 1.2 x 10
3
grams of ammonia, NH
3
? 1.2 x 10
3
x 17 = 70.59 moles
15) How many grams are in 2.3 x 10
-4
moles of calcium phosphate, Ca
3
(PO
3
)
2
? 2.3x10
-4
x 278 = 0.064 grams
16) How many moles are in 3.4 x 10
-7
grams of silicon dioxide, SiO
2
? 3.4x10
-7
/ 60 = 6.00 x 10
-9
moles
17) How many grams are in 1.11 moles of manganese sulfate, Mn
3
(SO
4
)
7
? 1.11 x 837 = 929.07 grams