Question

Prepare a 1.5 L of a 0.50 M solution of calcium nitrate. Determine the amount of calcium nitrate needed in correct significant figures.A) 77 gB) 120 gC) 306 gD) 490 g

Answer 1

120grams. Option B is correct

Explanations

The formula for calculating the molarity of a solution is expressed as:

`molarity=(mole)/(volume)`

Given the following parameters

• Volume of solution = 1.5L

,

• Molarity = 0.50M

Determine the moles of calcium nitrate

`\begin{gathered} moles=molarity* volume \\ moles=0.5M*1.5L \\ moles=0.75moles \end{gathered}`

Determine the mass of calcium nitrate

`\begin{gathered} mass=mole* molar\text{ mass} \\ mass=0.75\cancel{moles}*\frac{164.088g}{\cancel{mol}} \\ mass\text{ of Ca\lparen NO}_3\text{\rparen}_2=123grams \\ mass\text{ of Ca\lparen NO}_3\text{\rparen}_2\approx120grams \end{gathered}`

Hence the amount of calcium nitrate needed in correct significant figures is 120grams