Question

a chemist measures the amount of iodine solid produced during an experiment. she finds that 66.2 g of iodine solid is produced. calculate the number of moles of iodine solid produced.
be sure your answer has the correct number of significant digits.

Explanation:

Step1: Identify molar - mass of iodine

The molar mass of iodine ($I_2$) is $2\times126.90\ g/mol= 253.80\ g/mol$.

Step2: Use the formula for moles

The formula for the number of moles ($n$) is $n=\frac{m}{M}$, where $m$ is the mass and $M$ is the molar - mass. Given $m = 66.2\ g$ and $M=253.80\ g/mol$. Then $n=\frac{66.2\ g}{253.80\ g/mol}$.

Step3: Calculate the number of moles

$n=\frac{66.2}{253.80}\ mol\approx0.261\ mol$ (rounded to three significant digits as 66.2 has three significant digits).

Answer:

$0.261\ mol$