If 2.0 moles of a substance are dissolved in 2.0 liters of solution, then the molarity of this solution is:

1.) If 2.0 moles of a substance are dissolved in 2.0 liters of solution, then the molarity of this solution is:

0.5 M

1.0 M

1.5 M

2.0 M

2.) To make a 2.0-mole solution, how many moles of solute must be dissolved in 0.50 liters of solution?

Question 2 answers

0.25 moles solute

0.50 moles solute

1.0 mole solute

2.0 moles solute


3.) A common stain remover is sold as a concentrated solution of sodium hypochlorite (NaOCl). Diluting 55 milliliters of the concentrated solution to a total volume of 220 milliliters creates a solution that is a 0.40M sodium hypochlorite. What was the molarity of the original concentrated solution?

Question 3 Answers

0.10M

0.80M

1.6M

6.3M

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1: Molarity is moles of constituent divided by liters of solution. Therefore, 2.0 mol/2.0 liters = 1.0 M.

2: For this question, I'm assuming you mean "2.0 molar solution". If so, then the ratio of moles of constituent to liters of solution must be 2:1... therefore 1 mole of substance per 0.50 liters of solution would yield a 2.0 M solution (1.0 mol/0.50 L)

3: Remember to change milliliters to liters in this one!
55 mL = 0.055 L
220 mL = 0.22 L

X moles/0.22 L = 0.40 M
0.40 M x 0.22 L = 0.088 moles of hypochlorite in this solution.

0.088 moles hypochlorite/0.055 L solution = 1.6 M

You really aren't trying. Two moles in 2 liter? That is one mole per liter, usually referred to as 1 M.

Think of it this way. A 1 M solution means 1 mmole per mL. So you want 500 mL of a 2 M solution. You can do the simple arithmetic.