Question

1 pts
What is the molarity when 8.4 grams of NaF (molar mass = 42 grams/mol) is placed in 100
ml of water?

Answer 1

Answer:

molarity = 2 mol/ L

Explanation:

We know that molarity is equal to the number of moles of solute divided by volume of solution in litter.

Given data:

mass of NaF = 8.4 g

molar mass of NaF = 42 g/mol

volume of water = 100 mL

First of all we will convert the milliliter of solution in to litter.

we know that 1 litter is equal to 1000 mL.

100/ 1000= 0.1 L

Formula:

molarity = moles/ volume in litter

Now we will calculate the number of moles.

number of moles = mass/ molar mass

number of moles = 8.4 g/ 42 g/mol

number of moles = 0.2 mol

By putting the values in molarity formula, we will get,

molarity = 0.2 mol/ 0.1 L

molarity = 2 mol/ L