Question

12 calculate the mass of ammonium sulfate to prepare a 1.5m solution in 40 ml of di water. the molar mass of ammonium sulfate is 132.14 g/mol. 13. calculate the potassium chloride, kcl, to prepare a 1m solution in 100 ml of di water. molar mass = 74.55 g/mol

Explanation:

Step1: Convert volume to liters

The volume of water is $40\ mL$. Convert it to liters: $V = 40\ mL\times\frac{1\ L}{1000\ mL}=0.04\ L$ for the first - part. For the second - part, $V = 100\ mL\times\frac{1\ L}{1000\ mL}=0.1\ L$.

Step2: Calculate the number of moles using the molarity formula

The molarity formula is $M=\frac{n}{V}$, where $M$ is molarity, $n$ is the number of moles, and $V$ is volume. For ammonium sulfate, $n = M\times V$. Given $M = 1.5\ M$ and $V = 0.04\ L$, so $n_1=1.5\ mol/L\times0.04\ L = 0.06\ mol$. For potassium chloride, with $M = 1\ M$ and $V = 0.1\ L$, $n_2=1\ mol/L\times0.1\ L = 0.1\ mol$.

Step3: Calculate the mass using the molar - mass formula

The molar - mass formula is $m=n\times M_m$, where $m$ is mass, $n$ is the number of moles, and $M_m$ is molar mass. For ammonium sulfate, $M_m = 132.14\ g/mol$, so $m_1=0.06\ mol\times132.14\ g/mol = 7.9284\ g$. For potassium chloride, $M_m = 74.55\ g/mol$, so $m_2=0.1\ mol\times74.55\ g/mol = 7.455\ g$.

Answer:

For ammonium sulfate, the mass is $7.93\ g$ (rounded to two decimal places).
For potassium chloride, the mass is $7.46\ g$ (rounded to two decimal places).