Question

When determining the mass of product used or reactant consumed, the number of moles must be determined before comparing two substances because:

A. Atoms have the same mass but moles are different for each substance.
B. Different substances have different masses due to their atomic makeup.
C. Masses are the same for different substances.
D. Moles react.

Answer 1

The number of moles must be determined before comparing two substances because different substances have different masses due to their atomic makeup.

Step-by-step explanation:

When determining the mass of product used or reactant consumed, the number of moles must be determined before comparing two substances because:

1. Different substances have different masses due to their atomic makeup.
2. Atoms have the same mass but moles are different for each substance.
3. Masses are the same for different substances.
4. Moles react.

If we start with a known mass of one substance in a chemical reaction, we can convert that mass into moles using the substance's molar mass as the conversion factor. Then we can use the balanced chemical equation to construct a conversion factor to convert those moles into moles of another substance, which can be further converted into a corresponding mass. Determining the number of moles is important because it allows us to compare and calculate the masses of different substances involved in a reaction.