If 0.250 moles of NaOH are dissolved in 125g of water, what is the %m/m of NaOH in this solution?
I converted 0.250 mol to 10.0 g.
Then using the equation mass solute/mass solution * 100 I came up with the final answer of 7.41 %m/m.
Is that correct?
yes
Yes, your calculation is correct. To find the percent mass/mass (%m/m) of NaOH in the solution, you need to divide the mass of NaOH by the mass of the entire solution and multiply by 100.
First, you correctly converted the moles of NaOH to grams using the molar mass of NaOH (40.0 g/mol). So, 0.250 moles of NaOH is equal to 10.0 grams.
Next, you need to calculate the total mass of the solution. You are given that the solution contains 125 grams of water.
Finally, you can calculate the percent mass/mass (%m/m) of NaOH using the formula mass of solute (NaOH) divided by the mass of the entire solution (NaOH + water) multiplied by 100.
In this case, the mass of NaOH is 10.0 grams and the mass of the entire solution is 10.0 grams + 125 grams = 135 grams.
So, the calculation is:
(10.0 grams / 135 grams) * 100 = 7.41 %m/m
Therefore, your answer of 7.41 %m/m is correct.