A student mixes 0.79 grams of sodium carbonate into 50 mL of water. What is the molarity of the sodium carbonate solution?

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Answer 1 · 2018-03-19T12:08:12

#"0.15 M"#.

Molarity can be found with this formula:

#"molarity" = "number of moles"/"volume (L)"#

We know the volume, which is #"50 mL = 0.05 L"#.

We still need to know the number of moles, though, but we can find that from its mass.

#"0.79 g"# of #Na_2CO_3# is:

#"0.79 g"/"molar mass" = "0.79 g"/"105.99 g/mol" = "0.0075 mol"#

Now, we can just plug those values in to solve for molarity:

#"molarity" = "0.0075 mol"/"0.05 L" ="0.15 M"#