High School

Select the correct answer.

The atomic mass of potassium is 39.1. What is the mass of [tex]6.02 \times 10^{23}[/tex] atoms of potassium?

A. 39.1 mg
B. 39.1 g
C. 39.1 kg
D. [tex]6.02 \times 39.1[/tex] mg
E. [tex]6.02 \times 39.1[/tex] g

Answer :

Answer:

B) 39.1 g

Explanation:

To find the mass (in grams) of potassium we use stoichiometry, specifically using Avogadro's number and molar mass.

By using Avogadro's number we can convert the atoms to moles, from there we use the molar mass which is a ratio of grams of the compound to 1 mole to convert the calculated moles to grams of potassium.

[tex]\rm 6.02 \times 10^{23} ~atoms \cdot \dfrac{1 ~mol}{6.022 \cdot 10^{23}~atoms} \cdot \dfrac{39.1~g}{1~mole} = 39.08 ~g[/tex]

Our answer is close to answer choice B, so that's our final answer.

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