A laboratory assistant prepared 1 liter of a 40% aqueous sodium Hydroxide solution. how many grams of NaOH were needed to make this solution?
To find out how many grams of NaOH were needed to make a 40% aqueous solution of sodium hydroxide (NaOH), we need to understand the meaning of a 40% solution.
A 40% solution means that there is 40 grams of NaOH dissolved in every 100 milliliters (ml) of solution. Since we want to prepare a 1-liter (1000 ml) solution, we can set up a proportion to determine how many grams of NaOH are required.
40 grams of NaOH is to 100 ml solution as x grams of NaOH is to 1000 ml solution.
We can solve the proportion by cross-multiplying:
40 grams * 1000 ml = 100 ml * x grams
40,000 grams = 100 ml * x grams
Now, divide both sides of the equation by 100 ml to isolate x:
x grams = 40,000 grams / 100 ml
x grams = 400 grams
So, 400 grams of NaOH are needed to make a 1-liter (1000 ml) solution of 40% aqueous sodium hydroxide.