Question

A solution is prepared by dissolving 27.7 g of cacl2 in 375 g of water. the density of the resulting solution is 1.05 g/ml. the concentration of cacl2 is __________% by mass.

Answer 1

The concentration of ${\text{CaC}}{{\text{l}}_{\text{2}}}$ is $\boxed{6.88\;\%}$ by mass.

Further Explanation:

The proportion of substance in the mixture is called concentration. The most commonly used concentration terms are as follows:

1. Molarity (M)

2. Molality (m)

3. Mole fraction (X)

4. Parts per million (ppm)

5. Mass percent ((w/w) %)

6. Volume percent ((v/v) %)

Mass percent:

It is the ratio of the mass of a component divided by the total mass of the solution, multiplied by 100.

The formula to calculate the mass percent of ${\text{CaC}}{{\text{l}}_2}$ is as follows:

${\text{Mass}}\;{\text{percent of CaC}}{{\text{l}}_2} = \left( {\frac{{{\text{Mass of CaC}}{{\text{l}}_{\text{2}}}}}{{{\text{Mass of CaC}}{{\text{l}}_2}\;{\text{solution}}}}} \right)\left( {100} \right)$           …… (1)

The formula to calculate the mass of ${\text{CaC}}{{\text{l}}_2}$ solution is as follows:

${\text{Mass of CaC}}{{\text{l}}_{\text{2}}}{\text{ solution}} = {\text{Mass of CaC}}{{\text{l}}_{\text{2}}} + {\text{Mass of water}}$       …… (2)

The mass of ${\text{CaC}}{{\text{l}}_2}$ is 27.7 g.

The mass of water is 375 g.

Substitute these values in equation (2).

$\begin{aligned}{\text{Mass of CaC}}{{\text{l}}_{\text{2}}}{\text{ solution}}&=27.7{\text{ g}}+{\text{375 g}}\\&={\text{402}}{\text{.7 g}}\\\end{aligned}$

The mass of ${\text{CaC}}{{\text{l}}_2}$ is 27.7 g.

The mass of ${\text{CaC}}{{\text{l}}_2}$solution is 402.7 g.

Substitute these values in equation (1).

$\begin{aligned}{\text{Mass}}\;{\text{percent of CaC}}{{\text{l}}_2}&=\left( {\frac{{{\text{27}}{\text{.7 g}}}}{{{\text{402}}{\text{.7 g}}}}} \right)\left( {100} \right)\\&=6.8785\;\%\\&\approx 6.8{\text{8 \% }}\\\end{aligend}$

Therefore the mass percent of ${\mathbf{CaC}}{{\mathbf{l}}_{\mathbf{2}}}$ is 6.88 %.

Learn more:

1. What is the concentration of alcohol in terms of molarity?: brainly.com/question/9013318

2. What is the molality of the HCl solution? brainly.com/question/8426727

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Concentration terms

Keywords: mass percent, 6.88 %, mass of CaCl2, mass of water, mass of CaCl2, concentration, CaCl2, 27.7 g, 375 g, 402.7 g.

Answer 2

The answer is 6.88.
Solution:
We can calculate for the percent composition of CaCl2 by mass by dividing the mass of the CaCl2 solute by the mass of the solution and then multiply by 100. The total mass of the resulting solution is the sum of the mass of CaCl2 solute and the mass of water solvent. Therefore, the percent composition of CaCl2 by mass is 
     % by mass = (mass of the solute / mass of the solution)*100 
                        = mass of solute / (mass of the solute + mass of the solvent)*100
                        = (27.7 g CaCl2 / 27.7g + 375g) * 100 
                        = 6.88