Question

How are percent mass calculations used?

a.
They are used for determining concentrations in solutions and water of hydration
c.
They are used for determining water of hydration and the combustion analysis of hydrocarbons
b.
They are used for determining molecular purity and concentration in solutions
d.
None of the above

Answer 1

Percent mass calculations are used in chemistry to determine molecular purity and concentrations in solutions, aiding in stoichiometry problems, calculating molarity, and understanding composition from a compound's formula.

Step-by-step explanation:

Percent mass calculations are predominantly used in chemistry for various applications. Option b, which states that they are used for determining molecular purity and concentration in solutions, is correct. The mass/mass percent is defined as the mass of a solute divided by the mass of the solution times 100. This concept can be extremely useful when dealing with stoichiometry problems. For example, knowing the percent concentration of a solute can help calculate the molarity of a solution. This is useful in reactions that are carried out in solution and for determining the vapor pressures of mixtures of liquids.

Determining percent composition can also aid in calculating the amount of a solute when provided information such as the parts per million (ppm) concentration. Moreover, determining the formula mass of a compound and its percent composition by element from its chemical formula are foundational for understanding the compound's makeup and reactivity.

Answer 2

In my opinion, the correct answer among the choices presented above is option B. Percent mass calculations are useful in determining molecular purity and concentration in solutions. Percent mass is defined as the mass of a solute per mass of the solution multiplied by 100.