Download presentation

Presentation is loading. Please wait.

Published byDominick Small Modified over 8 years ago

2
CONCENTRATION OF SOLUTIONS Day 4

3
CONCENTRATION A measurement of the amount of solute in a given amount of solvent or solution (unit of measurement = molarity ) Kind of like the “strength” of the solution

4
MOLARITY Molarity (M)= mol solute L solution

5
VOLUME CONVERSION FACTORS 1 cm 3 = 1 mL 1 dm 3 = 1 L

6
DILUTE A dilute solution is a solution in which there is more solvent than solute. For example, to dilute some solution, you could add excess water to it.

7
EXAMPLE #1: If we put 0.500 mol of sodium hydroxide into 1.00 L of solution, what is the molarity of the solution?

8
Molarity= mol solute/L sol’n M= 2.00 L 0.50 mol NaOH = 0.25 M NaOH

9
Example #2: What is the molarity if we have 80.0 g NaOH in 1.00 L of solution?

10
Molarity= mol solute/L sol’n M= 1.00 L 2.00 mol NaOH = 2.00 M NaOH 80.0 g NaOH 40.0 g NaOH 1 mol NaOH =2.00 mol

11
EXAMPLE #3: How many moles of KOH are in 0.50 L of 0.10 M KOH?

12
Molarity= mol solute cross multiply! 1 L sol’n mol KOH= (0.50 L) (0.10 M KOH) = 0.05 mol KOH

13
EXAMPLE #4 How many grams of KOH are in 2.75 L of 0.25 M KOH?

14
Molarity = moles cross multiply! L Moles = Molarity * L = 0.25 mol/L * 2.75L = 0.69 moles KOH 0.69 mol KOH 56.097 g KOH = 38.7 g KOH 1 mole KOH (39)

15
MOLARITY - DILUTION Some chemicals are sold as pre-prepared concentrated solutions (stock solutions). To be used, stock solutions usually must be diluted.

16
A LWAYS A DD A CID

17
MOLARITY – DILUTION CALCULATIONS M 1 V 1 = M 2 V 2 M 1 – Molarity of stock solution V 1 – Volume of stock solution (L or mL) M D – Molarity of dilute solution V D – Volume of dilute solution (L or mL) Stock (original)Dilute (new solution)

18
*In dilution calculations, the units for volume must be the same.

19
2.) MOLARITY - DILUTION Example #1: How much 12.0 M HCl is required to make 2.50 L of a 0.500 M solution? M s * V s = M D * V D

20
M S V S = M D V D OR M 1 V 1 = M 2 V 2 M S = 12.0 M HCl M D = 0.500 M HCl V S = ?? V D = 2.50 L V S = (0.500 M HCl) (2.50 L) (12.0 M HCl) = 0.104 L HCl

21
2.) MOLARITY - DILUTION Example #2: What volume of a 1.50 M solution can be made using 0.0250 L of 18.0 M H 2 SO 4 ? M S V S = M D V D

22
M S V S = M D V D M S = 18.0 M H 2 SO 4 M D = 1.50 M H 2 SO 4 V S =.0250 L V D = ???? V D = (18.0 M ) (18.0 M H 2 SO 4 ) (.0250 L) (1.50 M ) (1.50 M H 2 SO 4 ) = 0.300 L 0.300 L H 2 SO 4

Similar presentations

© 2024 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google