Question

1 mole = molar mass (could be atomic mass from periodic table or molecular mass)

Total grams = Moles given moles x element mass = grams
Each element



1) How many moles are in 15 grams of lithium? (molar mass of lithium is 7 g/mole)

15 grams x 1 mole OR 15 grams = 2.14 moles lithium
7 grams 7 grams


2) How many grams are in 2.4 moles of sulfur? (molar mass of sulfur is 32 g/ mole)

2.4 moles x 32 grams OR 2.4 moles x 32 grams = 76.8 grams sulfur
1 mole


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?

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?

9) How many grams are in 4.5 moles of NaF?

10) How many moles are in 98.3 grams of Al(OH)3?

11) How many grams are in 0.02 moles of BeI2?

12) How many grams are in 3.3 moles of K2S?

Answer 1

Here are the conversions. I show the molar mass used and the calculation set-up for each.

3) How many moles are in 22 g of Ar?
- Molar mass Ar = 39.948 g/mol
- Moles = 22.0 g / 39.948 g/mol = 0.551 mol

4) How many grams are in 88.1 moles of Mg?
- Molar mass Mg = 24.305 g/mol
- Grams = 88.1 mol × 24.305 g/mol = 2141 g

5) How many moles are in 2.3 g of P?
- Molar mass P = 30.974 g/mol
- Moles = 2.30 g / 30.974 g/mol = 0.0743 mol

6) How many grams are in 11.9 moles of Cr?
- Molar mass Cr ≈ 52.00 g/mol
- Grams = 11.9 mol × 52.00 g/mol = 618.8 g

7) How many moles are in 9.8 g of Ca?
- Molar mass Ca = 40.078 g/mol
- Moles = 9.80 g / 40.078 g/mol = 0.2446 mol (0.245 mol)

8) How many grams are in 238 moles of As?
- Molar mass As = 74.922 g/mol
- Grams = 238 mol × 74.922 g/mol = 17,831 g

9) How many grams are in 4.5 moles of NaF?
- Molar mass NaF = 22.9898 + 18.9984 = 41.9882 g/mol
- Grams = 4.50 mol × 41.9882 g/mol = 189 g

10) How many moles are in 98.3 g of Al(OH)3?
- Molar mass Al(OH)3 = 26.9815 + 3×(15.999 + 1.008) = 78.003 g/mol
- Moles = 98.3 g / 78.003 g/mol = 1.260 mol

11) How many grams are in 0.02 moles of BeI2?
- Molar mass BeI2 = 9.0122 + 2×126.9045 = 262.821 g/mol
- Grams = 0.0200 mol × 262.821 g/mol = 5.26 g

12) How many grams are in 3.3 moles of K2S?
- Molar mass K2S = 2×39.0983 + 32.06 = 110.257 g/mol
- Grams = 3.30 mol × 110.257 g/mol = 364 g

If you want different rounding or more/less significant figures, tell me which problems and I’ll adjust.