Question

PROBLEMS

1. What is the molarity of 4 grams of NaOH dissolved in 1 liter of solution?

2. What is the molarity of 4 grams of NaOH dissolved in 0.5 liter of solution

3. What is the molarity of 4 grams of NaOH dissolved in 0.1 liter of solution

4. Which of the 3 solutions above is more concentrated and why?​

Answer 1

1.) 0.1 M

2.) 0.2 M

3.) 1 M

4.) Solution #3 is the most concentrated because it has the highest molarity. This solution has the largest solute to solvent ratio. The more solvent there is, the lower the concentration and molarity.

Step-by-step explanation:

To find the molarity, you need to (1) convert grams NaOH to moles (via molar mass from periodic table) and then (2) calculate the molarity (via the molarity equation). All of the answers should have 1 sig fig to match the given values.

Molar Mass (NaOH): 22.99 g/mol + 16.00 g/mol + 1.008 g/mol

Molar Mass (NaOH): 39.998 g/mol

4 grams NaOH 1 mole
---------------------- x ------------------ = 0.1 moles NaOH
39.998 g

1.)

Molarity = moles / volume (L)

Molarity = (0.1 moles) / (1 L)

Molarity = 0.1 M

2.)

Molarity = moles / volume (L)

Molarity = (0.1 moles) / (0.5 L)

Molarity = 0.2 M

3.)

Molarity = moles / volume (L)

Molarity = (0.1 moles) / (0.1 L)

Molarity = 1 M