Question

25.0 g of sucrose, c₁₂h₂₂o₁₁, are dissolved in water to make 250.0 ml of solution. what is the molar concentration of sucrose in this solution?
o 0.1
o 1.17
o 0.292
o 3.75

Explanation:

Step1: Calculate molar mass of sucrose

The molar mass of $C_{12}H_{22}O_{11}$ is calculated as follows:
For carbon ($C$): $12\times12.01\ g/mol = 144.12\ g/mol$
For hydrogen ($H$): $22\times1.01\ g/mol=22.22\ g/mol$
For oxygen ($O$): $11\times16.00\ g/mol = 176.00\ g/mol$
The molar mass $M$ of $C_{12}H_{22}O_{11}$ is $M=(144.12 + 22.22+176.00)\ g/mol=342.34\ g/mol$.

Step2: Calculate number of moles of sucrose

The number of moles $n$ of sucrose is given by the formula $n=\frac{m}{M}$, where $m = 25.0\ g$ and $M = 342.34\ g/mol$. So $n=\frac{25.0\ g}{342.34\ g/mol}\approx0.0730\ mol$.

Step3: Convert volume of solution to liters

The volume $V$ of the solution is $250.0\ mL$. Since $1\ L = 1000\ mL$, $V = 250.0\ mL\times\frac{1\ L}{1000\ mL}=0.250\ L$.

Step4: Calculate molar concentration

The molar concentration $C$ (molarity) is given by the formula $C=\frac{n}{V}$. Substituting $n = 0.0730\ mol$ and $V=0.250\ L$ into the formula, we get $C=\frac{0.0730\ mol}{0.250\ L}=0.292\ M$.

Answer:

0.292