Question

How many liters of a 4M solution can be made using 100 grams of LiBr?

Answer 1

Answer:

volume = 0.288 L

Explanation:

To find the volume, you need to (1) convert grams LiBr to moles LiBr (via molar mass) and then (2) calculate volume (via molarity equation). It is important to arrange the ratios in a way tat allows for the cancellation of units (desired units in the numerator).

(Step 1)

Molar Mass (LiBr): 6.9410 g/mol + 79.904 g/mol

Molar Mass (LiBr): 86.845 g/mol

100 grams LiBr           1 mole
-----------------------  x  ------------------  =  1.15 moles LiBr
                                  86.845 g

(Step 2)

Molarity (M) = moles / volume (L)

4 M = 1.15 moles / volume

(4 M) x volume = 1.15 moles

volume = 1.15 moles / 4 M

volume = 0.288 L