Question

What is the molarity of a solution of 14.0 g NH4Br in enough H2O to make 150 mL of solution?

Answer 1

The molarity of a solution equals to the mole number of the solute/the volume of the solution. For NH4Br, we know that the mole mass is 98. So the molarity is (14/98) mol /0.15 L=0.95 mol/L.

Answer 2

Explanation:

Molarity is defined as the number of moles per liter of solution.

Mathematically,         Molarity = $\frac{no. of moles}{volume of solution in liter}$

Since it is given that the molarity of a solution of 14.0 g and volume is 150 mL or 0.15 L.

Whereas number of moles = $\frac{mass}{molar mass}$

So, molar mass of $NH_{4}Br$ is 97.94 g/mol.

Thus,      number of moles = $\frac{14.0 g}{97.94 g/mol}$

                                            = 0.142 mol

Therefore, calculate the molarity as follows.

              Molarity = $\frac{no. of moles}{volume of solution in liter}$  

                             = $\frac{0.142 mole}{0.15 L}$

                              = 0.946 mol/L

Hence, we can conclude that molarity of the solution is 0.946 mol/L.