How many liters of 4 M solution can be made using100 grams of lithium bromide?


Adrian Dingle, Educator and Chemistry Author with 25 years teaching experience

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You need to know the relationship between mass and moles for a solid, and concentration & volume and moles for a solution. Also know that '4M' = 4 mol/L and is a unit of concentration.

  • Convert the mass of LiBr to moles, by dividing by the molar mass (taken from the periodic table) of LiBr.

100 g / (7 + 80 g/mol) = 1.15 moles of LiBr

  • Knowing that in a solution, moles = (concentration in mol/L) x (volume in L), substitute the values and do the algebra.

1.15 moles = (4 mol/L) x (volume in L)

volume in L = 0.288 L

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