Question

Which equivalence factor should you use to convert from 38.2 grams of K to moles of K?

a
(38.2 g K/39.10 g K)
b
(38.2 g K/1 mol K)
c
(1 mol K/38.2 g K)
d
(1 mol K/39.10 g K)

Answer 1

Answer: (38.2 g K/39.10 g K)

Step-by-step explanation:

To convert given masses into moles we use the formula :

Moles of K=
`\frac{\text{ given mass of K}}{\text{ molar mass of K}}`

Given:

Mass of K= 38.2 grams

Molar mass of K= 39.10 g/mol

Putting in the values in the given formula, we get:

Moles of K=
`(38.2g)/(39.10g/mole)=0.98moles`

Thus the moles are 0.98 moles.

Answer 2

In order convert the mass of a substance to its number of moles The conversion factor is the reciprocal of the molecular weight of the substance. Hence, for the given element in the problem- potassium, the equivalence factor is d. (1 mol K/39.10 g K).