Question #5daf3

1 Answer
May 18, 2015

Your solution's concentration by mass will be equal to 35.5%.


To get a solution's concentration by mass, sometimes called percent by mass, or #"m/m%"#, you need to divide the mass of solute by the total mass of the solution, and multiply this ratio by 100.

#"m/m%" = "mass of solute"/"total mass of solution" * 100#

So, you're dissolving 55.00 g of potassium hydroixe in 100 g of water. The mass of the solute will be equal to that of the potassium hydroxide.

The mass of the solution, however, will be equal to

#m_"solution" = m_"solute" + m_"solvent"#

In your case, you have

#m_"solution" = 55.00 + 100 = "155 g"#

This will make the solution's concentration by mass equal to

#"m/m%" = (55.00cancel("g"))/(155cancel("g")) * 100 = color(green)("35.5%")#