Question

How many moles are present in 10.5 grams of NaCl?

0.180 mol
0.18 mol
0.457 mol

Answer 1

N(number of moles)=mass/molar mass

10.5=mass

Na=23 (rounded)

Cl=36 (rounded)

Add it together to get the molar mass

=59

Then refer back to the formula

10.5/59

=0.17796

Round that answer

=0.18 mol

Answer 2

Answer : The correct option is, 0.180 mole

Explanation : Given,

Mass of NaCl = 10.5 g

Molar mass of NaCl = 58.5 g/mole

Formula used :

`\text{Moles of NaCl}=\frac{\text{Mass of NaCl}}{\text{Molar mass of NaCl}}`

Now put all the given values in this formula, we get the moles of NaCl.

`\text{Moles of NaCl}=(10.5g)/(58.5g/mole)`

`\text{Moles of NaCl}=0.179mole=0.180mole`

Therefore, the number of moles of NaCl is, 0.180 mole