9. A student needs to prepare 100 mL of a 0.50 M ammonium chloride, NH4Cl, solution. How much solute does he need?

2.67g of NH4Cl are required

Explanation:

Molarity is an unit of concentration in chemistry defined as the moles of solute (In this case, NH4Cl), per liter of solution.

To prepare 100mL of a 0.50M are required:

100mL = 0.100L * (0.50 moles / L) = 0.0500 moles NH4Cl

As molar mass of NH4Cl is 53.491g/mol:

0.0500 moles * (53.491g / mol) =

right

explanation:

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.