You have 1500.0 g of a bleach solution. The percent by mass of the solute sodium hypochlorite, #NaOCl#, is 3.62%. How many grams of #NaOCl# are in the solution?

1 Answer
Jan 17, 2016

Answer:

#"54.3 g NaOCl"#

Explanation:

The key to this problem lies with the definition of percent concentration by mass, #"m/m %"#.

As you know, percent concentration by mass is defined as the ratio between the mass of the solute and the total mass of the solution, multiplied by #100#.

#color(blue)("% m/m" = "mass of solute"/"mass of solution" xx 100)#

You are told that your bleach solution has a #"3.62%# percent concentration by mass. Looking at the above definition, that should tell you that every #"100 g"# of solution will contain #"3.62 g"# of sodium hypochlorite, your solute.

In your case, the mass of the solution is said to be equal to #"1500.0 g"#. This means that it will contain

#1500.0 color(red)(cancel(color(black)("g solution"))) * "3.62 g NaOCl"/(100color(red)(cancel(color(black)("g solution")))) = color(green)("54.3 g NaOCl")#

Alternatively, you can use the equation for percent concentration by mass to find the mass of the solute

#"% m/m" = m_"solute"/m_"solution" xx 100#

#m_"solute" = ("%m/m" * m_"solution")/100#

Plug in your values to get

#m_"solute" = (3.62 * "1500.0 g")/100 = color(green)("54.3 g NaOCl")#

Here's a useful video on percent concentration by mass