Question

question 7
1 pts
for a compound whose formula is known, the percent composition is derived from its____ and the____ of its constituent elements.
combined atomic number, atomic number
formula mass, atomic masses
formula mass, atomic radius
isotopic abundance, atomic masses

Explanation:

The percent composition of a compound is calculated using the formula \(\text{Percent Composition}=\frac{\text{Mass of Element in Compound}}{\text{Formula Mass of Compound}}\times100\%\). The mass of the element in the compound depends on the atomic masses of the constituent elements (from the periodic table), and the formula mass of the compound is calculated by summing up the atomic masses of all the atoms in the formula. Atomic number is related to the number of protons and not directly to mass - based percent composition. Atomic radius is a measure of the size of an atom and not relevant to mass - based percent composition. Isotopic abundance is used in calculating the average atomic mass of an element (not directly in percent composition of a compound from its formula).

Answer:

formula mass, atomic masses