Question

1 true or false 1 point
the formula mass of a compound is the sum of the atomic weights of each element in its chemical formula.
true
false
2 multiple choice 1 point
what information is not needed to calculate percent composition?
the atomic weight of the target element
the state of matter of the compound
the formula weight of the compound
the number of atoms of the target element
3 true or false 1 point
the molecular mass applies to ionic compounds.
true
false

Explanation:

Question 1

The formula mass (or formula weight) of a compound is indeed calculated by summing the atomic weights of all the atoms in its chemical formula, considering the number of each atom. So the statement is True.

To calculate percent composition of an element in a compound, the formula is $\% \text{ composition} = \frac{\text{(number of atoms of element)} \times \text{(atomic weight of element)}}{\text{formula weight of compound}} \times 100\%$. The state of matter (solid, liquid, gas) of the compound does not affect these calculations, while atomic weight of the element, formula weight of the compound, and number of atoms of the element are all needed.

Molecular mass is used for covalent compounds (molecules) to represent the mass of a single molecule. Ionic compounds do not exist as discrete molecules, so we use formula mass for them instead of molecular mass. Thus, molecular mass does not apply to ionic compounds, making the statement False.

Answer:

True

Question 2