Question

select the correct answer. james needs 4.20 moles of nabr for an experiment. how many grams of nabr must he measure out to have 4.20 moles? a. 245 b. 103 c. 183 d. 432

Explanation:

Step1: Find molar - mass of NaBr

The molar - mass of Na (sodium) is approximately 23 g/mol and the molar - mass of Br (bromine) is approximately 80 g/mol. So, the molar - mass of NaBr, $M = 23+80=103$ g/mol.

Step2: Calculate mass using moles and molar - mass

We know that the number of moles $n = 4.20$ mol and the formula $m=n\times M$. Substituting the values, we get $m = 4.20\times103=432.6\approx432$ g.

Answer:

A. 425