Question

PROBLEMS

Answer 1

Answer:

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.

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