Question

What volume of 0.716 M KBr solution is needed to provide 10.5 g of KBr

Answer 1

Use the formula for molarity to answer this question.

Molarity = (moles of solute)/liters of solution

First find the moles of the KBr

n(# of moles) = mass/GMW
n = 10.5g/ (39.1g + 79.9g)
n = 0.088 moles

Now place into the molarity equation

Molarity = (moles of solute)/liters of solution

0.716 M = 0.088 moles/V

V = 0.088/0.716 = 0.1229 L

Therefore, the volume of 0.716 M KBr solution is needed to provide 10.5 g of KBr is 0.1229 L

Answer 2

\[n=\frac{ mass }{ molar mass }\] \[C=\frac{ no. moles }{ volume }\]
hence finding vol. is \[V=\frac{ no. moles }{ conc.}\] so conc.=0.716M andmass=10.5g
finding the moles you will get 0.088moles using the above mole formular.
hence V=\[\frac{ 0.088 }{ 0.716 }=v\] V=0.1229L