Practice Grams (Mass) in Chemistry
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
A gram (g) is the fundamental unit of mass in chemistry, defined as one thousandth of a kilogram.
Grams tell you how heavy something is. A paperclip is about 1 gram. Moles tell you how many particles you have—a completely different question.
Example 1
easyConvert 2.50 moles of sodium chloride (NaCl) to grams. (Molar mass of NaCl = 58.44\,\text{g/mol})
Example 2
mediumHow many moles are in 49.0 g of sulfuric acid (\text{H}_2\text{SO}_4)? How many molecules does this represent? (Molar mass = 98.09\,\text{g/mol})
Example 3
mediumWhat mass in grams of iron is needed to provide 2.00 \times 10^{24} atoms of iron? (Fe = 55.85\,\text{g/mol})
Example 4
hardIn the reaction 2\text{Al} + 3\text{Cl}_2 \rightarrow 2\text{AlCl}_3, calculate the mass in grams of \text{AlCl}_3 produced from 13.5 g of aluminum reacting with excess chlorine. (Al = 26.98, Cl = 35.45\,\text{g/mol})