Question

What is the molariity of a 50.0 mL aqueous solution containing 10.0 grams of hydrogen peroxide, H2O2?

Answer 1

Answer:

6 mol/L

Explanation:

You should know or have the equation to solve for Molarity which is;

M = n/v          (M: Molarity) (n: moles of solute) (v: Liters of solute)

You can start off differently but I would start by converting the mL to L. This is your "v" value.

50.0 mL/ 1000 mL = 0.05 L

Now, you have to convert grams to moles in order to solve for molarity (M).

1.) On the periodic table find the molecular weights of H and O.

H= 1.01 g/mol         O= 16.00 g/mol

2.) Multiply them and then add them together to have their combined molecular weights. (You have to multiply by 2 because of their equation; H2O2).

2(1.01) + 2(16.00)= 34.02 g/mol

3.) Now, you're going to use the "picket fence method" or whichever your teacher taught you to convert from grams to moles. This will be your "n" value. (I cannot show it on here without it looking weird, so my sincere apologies.)

10.0 g/ 34.02 g = 0.2939 mol

4.)You are now going to plug in your answers into the equation for Molarity.

M= 0.2939 mol / 0.05 L = 5.878 mol/L

5.) I am sure your professor might be a stickler so for sig figs sake when you multiply or divide use the smallest amount of sig figs you see which is 1. Round 5.878 to 6 mol/L

Sorry this explanation is very long let me know if you need a better more written out explanation.