Question

Which of the following substances has the highest percent by mass of chlorine?

1) Sodium chloride (NaCl)
2) Calcium chloride (CaCl2)
3) Hydrochloric acid (HCl)
4) Chlorine gas (Cl2)

Answer 1

Calcium chloride (CaCl2) has the highest percent by mass of chlorine.

Step-by-step explanation:

The substance with the highest percent by mass of chlorine is calcium chloride (CaCl2).

To determine this, we need to calculate the percent by mass of chlorine for each substance.

1. Sodium chloride (NaCl): This compound has a 1:1 ratio of sodium and chlorine, so the percent by mass of chlorine is 35.45 amu / 58.44 amu x 100% = 60.72%.
2. Calcium chloride (CaCl2): This compound has a 1:2 ratio of calcium and chlorine, so the percent by mass of chlorine is (70.90 amu x 2) / 110.98 amu x 100% = 63.65%.
3. Hydrochloric acid (HCl): This compound consists of one hydrogen atom and one chlorine atom, so the percent by mass of chlorine is 35.45 amu / 36.46 amu x 100% = 97.00%.
4. Chlorine gas (Cl2): This molecule consists of two chlorine atoms, so the percent by mass of chlorine is (35.45 amu x 2) / 70.90 amu x 100% = 100.00%.

Therefore, calcium chloride (CaCl2) has the highest percent by mass of chlorine.