If 625 ml of pure water is added to 344 ml of 1.675 m na2so4, what is the new concentration of na2so4?

Molar concentration is the number of Na₂SO₄ moles that are dissolved in 1 L of solution.
when 625 mL is added to 344 mL of Na₂SO₄, then the number of moles that are dissolved in 344 mL remains constant but volume increases. Therefore concentration now decreases. 
Molar concentration of Na₂SO₄ is 1.675 M
the number of Na₂SO₄ moles  in 1000 mL - 1.675 mol
then number of Na₂SO₄ moles in 344 mL - 1.675 mol / 1000 x 344 = 0.5762 mol
the new volume - 344 mL + 625 mL = 969 mL
concentration = number of moles / volume
therefore new concentration = 0.5762 mol / 0.969 L = 0.595 mol/L
new concentration of Na₂SO₄ is 0.595 M

If the water vapor content stays the same and the temperature drops, then the relative humidity increases. its vise versa.if the water vapor content stats the same and the temperature rises, the relative humidity decreases. so, yes, i'd say that temperature and humidity have a strong relationship.

The answer to this problem is. 67