Question

a chemist determined by measurements that 0.055 moles of aluminum participated in a chemical reaction. calculate the mass of aluminum that participated in the chemical reaction. be sure your answer has the correct number of significant digits.

Explanation:

Step1: Recall molar - mass formula

The formula to calculate mass ($m$) from moles ($n$) and molar mass ($M$) is $m = n\times M$. The molar mass of aluminum ($Al$) is $M_{Al}=26.98\ g/mol$.

Step2: Substitute values

We are given $n = 0.055\ mol$ and $M_{Al}=26.98\ g/mol$. Substitute these values into the formula: $m=0.055\ mol\times26.98\ g/mol$.

Step3: Calculate the mass

$m = 0.055\times26.98=1.4839\ g$.

Step4: Apply significant - digits rule

The number of moles ($0.055$) has two significant digits. So, the mass should be reported with two significant digits. Rounding $1.4839\ g$ to two significant digits gives $1.5\ g$.

Answer:

$1.5\ g$