Question

Which quantity can be calculated for a solid compound, given only the formula of the compound and the Periodic Table of the Elements?

(1) the density of the compound

(2) the heat of fusion of the compound

(3) the melting point of each element in the compound

(4) the percent composition by mass of each element in the compound

Answer 1

The answer is the percent composition which is number 4. This is the percent by mass of each element existing in a compound. To compute for this, you need to find two things: the mass of just the element, and the molar mass of the entire compound. Afterwards, you take the molar mass of only the element and divide it by the molar mass of the entire compound, and multiply by 100%.