Question

How many moles of salt are in 1.005 kg of NaCl? (Hint: 1 kg = 1000g)

O 17.8 mol
18.0 mol
17.2 mol
O 18.2 mol

Answer 1

The answer is

17.2 mol

Step-by-step explanation:

To find the number of moles in a substance when given the molar mass and mass we use the formula

`n = (m)/(M )`

where

n is the number of moles

M is the molar mass

m is the mass of the substance

Mr( Na) = 23 , Mr( CL ) = 35.5

Molar mass ( NaCl ) = 23 + 35.5

= 58.5 g/mol

Mass = 1.005 kg

It's equivalent in grams is

1.005 × 1000 = 1005 g NaCl

So the number of moles in NaCl is

`n = (1005)/(58.5) \\ = 17.179487...`

We have the final answer as

17.2 mol to the nearest tenth

Hope this helps you