# Help Zone

### Student Question

Secondary III • 7mo.

I need some help with those 2 questions -how do I start? thank you for your help.

Science

## Explanations (1)

• Explanation from Alloprof

Explanation from Alloprof

This Explanation was submitted by a member of the Alloprof team.

Options
Team Alloprof • 7mo.

Hi SupraArgon8691,

To answer both questions, you'll need the concentration formula :

In your case, the concentrations are in millilitres, but the formula is the same.

Question 1 :

You know the concentration and the volume, you can find the corresponding mass with the formula.

Question 2 :

When a concentration is given in percentages, the quantity of solute for a quantity of the solution is equivalent to 100. In your case, the concentration is 6g per 100 mL.

You can put this concentration and the mass of NaCl in the formula to find the corresponding volume.

Here's a concept sheet from our website if you want to see a few examples :

I hope that helps and feel free to write us again!

Anthony B.