Question

What is the concentration of copper sulphate (in $mol{\text{ }}{L^{ - 1}}$ ) if 80 g of it is dissolved in enough water to make a final volume of 3 L?
A. 0.0167
B. .167
C. 1.67
D. 10.67

Answer 1

Hint : Molar concentration (also known as molarity, quantity concentration, or substance concentration) is a measurement of a chemical species' concentration in a solution in terms of the amount of substance per unit volume of solution. The number of moles per litre, abbreviated as mol/L in SI units, is the most often used unit for molarity in chemistry.

Complete Step By Step Answer:
The mass of a sample of a chemical compound divided by the amount of material in that sample, measured in moles, is the molar mass of that compound in chemistry. In grams, it is the mass of 1 mole of the material, or $6.022 \times {10^{23}}$ particles. The molar mass of a material is a bulk attribute, not a molecular attribute. The molar mass is a weighted average of several different occurrences of the chemical, which might vary in mass due to isotopes.
The amount of moles of solute per litre of solution is known as molarity (M). Molarity is defined as the number of moles of solute per litre of solution.
$M = \dfrac{n}{V}$
The molar mass of $CuS{O_4}$ is 159.5 g/mol
Now the given mass is 80 g/mol
Now to find the number of moles we get
$n = \dfrac{{{\text{Given Molar Mass}}}}{{{\text{Molecular Mass}}}}$
$n = \dfrac{{80}}{{159.5}} = 0.5{\text{ }}mole$
Now
$M = \dfrac{n}{V}$
Hence
$M = \dfrac{{0.5}}{3} = 0.167{\text{ mol}}{{\text{L}}^{ - 1}}$ .

Note :
The use of molar concentration in thermodynamics is frequently inconvenient since the volume of most solutions varies somewhat with temperature owing to thermal expansion. This difficulty is typically overcome by utilising temperature adjustment factors or a temperature-independent concentration measure such as molality. The reciprocal amount denotes the dilution (volume) that may be found in Ostwald's dilution law.