Asolution of naoh has a concentration of 25.00% by mass. what mass of naoh is present in 0.250 g of this solution? use the periodic table in the toolbar if needed. 0.0625 g what mass of naoh must be added to the solution to increase the concentration to 30.00% by mass? g

1) 0.0625  g.

2) 0.0125 g.

Explanation:

1) A solution of NaOH has a concentration of 25.00% by mass. What mass of NaOH is present in 0.250 g of this solution?

mass% of NaOH = [(mass of NaOH)/(mass of solution)] x 100.

mass% of NaOH = 25.0%, mass of NaOH = ???  g, mass of solution = 0.250 g.

∴ mass of NaOH = (mass% of NaOH)(mass of solution)/100 = (25.0%)(0.250 g)/100 = 0.0625  g.

2) What mass of NaOH must be added to the solution to increase the concentration to 30.00% by mass?

We can use the relation:

mass% of NaOH = [(mass of NaOH)/(mass of solution)] x 100.

mass% of NaOH = 30.0%, mass of NaOH = ???  g, mass of solution = 0.250 g.

∴ mass of NaOH = (mass% of NaOH)(mass of solution)/100 = (30.0%)(0.250 g)/100 = 0.075  g.

∴ The mass of NaOH should be added = 0.075 - 0.0625 = 0.0125 g.

the answer is barium and copper bromide

if the temperature drops and becomes cool

then the atmosphere can be freezing as the water vapor in the air is at maximum (100%) and can be severely cold

also can be snowing lightly as the moisture in the air will start to solidify

and btw this is not chemistry but