Choose an arbitrary quantity of your favorite solute (for example, 10 grams NaCl
ID: 1001873 • Letter: C
Question
Choose an arbitrary quantity of your favorite solute (for example, 10 grams NaCl) and solvent (for example, 1 L H2O). Calculate the solution concentration in units of molarity, percent by mass, and percent by volume. Please explain how you did it. Choose an arbitrary quantity of your favorite solute (for example, 10 grams NaCl) and solvent (for example, 1 L H2O). Calculate the solution concentration in units of molarity, percent by mass, and percent by volume. Please explain how you did it. Choose an arbitrary quantity of your favorite solute (for example, 10 grams NaCl) and solvent (for example, 1 L H2O). Calculate the solution concentration in units of molarity, percent by mass, and percent by volume. Please explain how you did it.Explanation / Answer
Answer – We assume , mass of NaCl = 10 g, volume of water = 1 L = 1000 mL
We know the density of water = 1.00 g/mL
We need to calculate the moles of NaCl for molarity, since molarity is moles per liter of volume.
Moles of NaCl = 10 g / 58.443 g.mol-1
= 0.171 moles
We know,
Molarity = moles / L
Molarity of NaCl = 0.171 moles / 1.0 L
= 0.171 M
We know, percent by mass means mass of solute by total mass of solution multiply by 100
percent by mass of NaCl = mass of NaCl / total mass of solution * 100 %
mass of solvent = density of solvent * volume
= 1.00 g/mL * 1000 mL
= 1000 g
Total mass of solution = 10 +1000 = 1010 g
percent by mass of NaCl = 10 g /1010 g *100 %
= 0.99 %
We know, percent by volume means mass of solute by total volum of solution multiply by 100. Volume not changing when 10 g of NaCl added in to the 1 L or 1000 mL of water, so volume of solution is 1000 mL.
percent by volume of NaCl = 10 g /1000 mL *100 %
= 1.0 %