Completed question:
When chemists work with solid materials, we simply weigh out amounts of solid reagents and calculate mole amounts when thinking about stoichiometry. However, when we dissolve a solid (also known as a solute) in a solvent to form a solution, the solute becomes evenly distributed throughout the solution and we need to know how many moles of solute are present in a particular volume of solution. A solution is created by dissolving 11.0 grams of ammonium chloride in enough water to make 215 mL of solution.
How many moles of ammonium chloride are present in the resulting solution? ___moles of NH4Cl
When thinking about the amount of solute present in a solution, chemists report the concentration or molarity of the solution. Molarity is calculated as moles of solute per liter of solution. What is the molarity of the solution described above? ____M
Answer:
Number of moles of NH4Cl = 0.2056moles
Molarity = 0.956M
Explanation:
Number of moles =[tex]\frac{mass}{molar mass}[/tex]
molar mass of NH4Cl = 14 +(4*1) +35.5 = 53.5g/mol
mass of [tex]NH_{4}Cl[/tex]= 11g
number of moles of [tex]NH_{4}Cl[/tex]= [tex]\frac{11}{53.5}[/tex]
= 0.2056 moles
Molarity of a solution refers to the number of moles present in [tex]1dm^{3}[/tex] of solution.
[tex]1dm^{3}[/tex] = 1 Litre.
if 0.2056 moles is present in 215mL of solution, we will find how many moles will be present in 1L of solution
= [tex]\frac{0.2056*1}{215^{-3} }[/tex]
= 0.956[tex]mol/dm^{3}[/tex]
= 0.956M solution.
