Question

a sample of bromine contains 45.3 grams. 1. how many moles of br atoms are there in the sample? 2. how many moles of br₂ molecules are there in the sample? use the references to access important values if needed for this question. 3 item attempts remaining

Explanation:

Step1: Recall molar - mass of Br

The molar mass of Br is approximately 79.90 g/mol.

Step2: Calculate moles of Br atoms

Use the formula $n=\frac{m}{M}$, where $m = 45.3$ g and $M=79.90$ g/mol. So, $n_{Br}=\frac{45.3}{79.90}\approx0.567$ mol.

Step3: Calculate moles of $Br_2$ molecules

Since 1 mole of $Br_2$ contains 2 moles of Br atoms, the number of moles of $Br_2$ is half the number of moles of Br atoms. So, $n_{Br_2}=\frac{n_{Br}}{2}=\frac{0.567}{2}= 0.2835$ mol.

Answer:

1. 0.567 mol Br
2. 0.2835 mol $Br_2$