James needs 4.20 moles of nabr for an experiment. how many grams of nabr must he measure out to have 4.20 moles?

Ans: Mass of NaBr = 432 g

Given:

# moles of NaBr = 4.20 moles

To determine:

The mass corresponding to 4.20 moles of NaBr

Explanation:

The # moles of a given substance is the ratio of its mass to molar mass

moles = mass (g)/molar mass (g.mol-1)(1)

Molar mass of NaBr = 102.89 g/mol

Based on equation(1)

mass = moles * molar mass

        = 4.20 moles * 102.89 g.mol-1 = 432 g

answer: a chemical reaction

explanation:

im not wrong

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.