Question

in a group assignment, students are required to fill 10 beakers with 0.720 m cacl₂. if the molar mass of cacl₂ is 110.98 g/mol and each beaker must have 250. ml of solution, what mass of cacl₂ would be used?
use molarity = \\(\frac{\text{moles of solute}}{\text{liters of solution}}\\)
\\(\bigcirc\\) 3.13 g
\\(\bigcirc\\) 38.5 g
\\(\bigcirc\\) 200 g
\\(\bigcirc\\) 617 g

Explanation:

Step1: Convert volume to liters

Each beaker has 250 mL, so for 10 beakers, total volume $V = 10\times250\space mL = 2500\space mL$. Convert to liters: $V=\frac{2500}{1000}\space L = 2.5\space L$.

Step2: Calculate moles of $CaCl_2$

Using molarity formula $M=\frac{n}{V}$, rearrange to $n = M\times V$. Given $M = 0.720\space M$ and $V = 2.5\space L$, so $n=0.720\space mol/L\times2.5\space L = 1.8\space mol$.

Step3: Calculate mass of $CaCl_2$

Mass $m = n\times Molar\space mass$. Molar mass of $CaCl_2$ is $110.98\space g/mol$, so $m = 1.8\space mol\times110.98\space g/mol\approx199.76\space g\approx200\space g$.

Answer:

200 g (Note: The precise calculation gives approximately 198 g, which is closest to 200 g among the options)