Question

What is the formula mass of the hypothetical compound A2R1Q1 if the atomic masses of A, R, and Q are 18.4, 12.6, and 24.7, respectively? Option 1: 73.6 Option 2: 55.3 Option 3: 31.7 Option 4: 46.1

Answer 1

74.1

Step-by-step explanation:

See the attached worksheet. The atomic mass of each element is multiplied by its element count to arrive at an atomic mass that element contributes to the intact molecule. Since the formula is A2R1Q1, both R and Q contribute only the atomic mass of one atom each. A has two atoms, so the atomic mass of A is doubled. Add these atomic masses to arrive at the formula mass of 74.1