Question

How many moles are in 63 g of NH4 (molar mass= 18g)?
a. 2 moles
b. 1 moles
c. 3.5 moles
d. 5 moles

Answer 1

To answer this question, all you to do is to divide the mass by the molar mass and that should get you your moles.

$=63g\ NH_{4}\ x\ \frac{1\ mol\ NH_{4}}{18g\ NH_{4}}$

= 3.5 mol NH₄

Answer 2

$\qquad \qquad\huge \underline{\boxed{\sf Answer}}$

Here's the solution ~

$\qquad \sf  \dashrightarrow \: 18g = 1 \: mole$

$\qquad \sf  \dashrightarrow \: 1g = \dfrac{1}{18} \: moles$

$\qquad \sf  \dashrightarrow \: 63g = \dfrac{1}{18} \times 63\: moles$

$\qquad \sf  \dashrightarrow \: 63g = \dfrac{7}{2} \: moles$

$\qquad \sf  \dashrightarrow \: 63g = 3.5 \: moles$

Correct choice is C