Answer:

Step-by-step explanation:
The number of moles of
can be found by using the formula

where
n is the number of moles
m is the mass in grams
M is the molar mass in g/mol
From the question
m = 87.5 g
Molar mass of
= (14×2) + 16 = 28 + 16 = 44 g/mol

We have the final answer as
1.99 moles