Question

A student measures out 130 grams of potassium bromide (KBr) for an experiment. How many moles would this be?(1 point) Responses 130g /119 g/mol = 1.09 mol 130g /119 g/mol = 1.09 mol 54 g/mol / 130 g = 0.41 mol 54 g/mol / 130 g = 0.41 mol 130 g / 54 g/mol = 2.4 mol 130 g / 54 g/mol = 2.4 mol 130 g x 11.9 g/mol = 1547 mol

Answer 1

To find the number of moles of potassium bromide (KBr), you can use the formula:

\[
\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}
\]

First, we need to calculate the molar mass of KBr. The molar mass of potassium (K) is approximately 39 g/mol, and the molar mass of bromine (Br) is approximately 80 g/mol.

So:

\[
\text{Molar mass of KBr} = 39 \, \text{g/mol (K)} + 80 \, \text{g/mol (Br)} = 119 \, \text{g/mol}
\]

Now, using the given mass of KBr:

\[
\text{moles of KBr} = \frac{130 \, \text{g}}{119 \, \text{g/mol}} \approx 1.09 \, \text{mol}
\]

Thus, the correct answer is:

**130g / 119 g/mol = 1.09 mol**