Download presentation

Presentation is loading. Please wait.

Published byAlexis Collins Modified over 5 years ago

1
Unit 8: Solutions Molarity

2
Concentration Concentration is a value that represents the amount of solute dissolved in a solvent. Concentrated solutions have a large amount of solute relative to the solvent Dilute solutions have a small amount of solute relative to the solvent Concentration can be measured in Molarity, %solution, ppm (parts per million)

3
Molarity Molarity is the moles of solute per liter of solution. Note the volume is the total solution volume, not the volume of solvent alone. M = moles = mass/molar mass Liters Liters This is the most common way chemists measure concentration

4
How it is made… 2 Molar Solution of NaCl requires 2 moles of NaCl to be dissolved to make 1L of solution 2 moles of salt (or 117 grams) are dissolved in 1L of water to make a 2M NaCl(aq) solution

5
Practice Problem #1 What is the molarity of HCl if 28g HCl is dissolved in 500.mL of solution? mass=28.gmolar mass of HCl= 36.46g/mol V= 500mL=0.500L (divide by 1000) M= moles = (mass/molar mass) Liter = (28/36.46)moles 0.500L = 1.5 M

6
Practice Problem #2 How many grams of sodium nitrate (NaNO 3 ) are needed to make 2 liters of a 0.100M solution? M=0.100Mm=?mm NaNO 3 = 85g/mol 0.100M = (m/85)mols 2L (0.100M)(2L)(85)= m m=17g NaNO 3

7
Solving using Dimensional Analysis Molarity can be used as a conversion factor. 2.0 L 0.100moles 85 grams = 17g 1 Liter 1 moles

8
Example 3 What is the molarity of a solution with 10.0 grams of AgNO 3 is dissolved in 500.mls of solution. Molarity = Mass / Molar Mass Liters of Solution M = 10.0g / 169.88 g/mol 0.500 Liters Must convert to Liters!! 500mls/ 1000 = 0.500 Liters M = 0.118 Molar

9
Example 4 How many grams of KNO 3 should be used to prepare 2.00 Liters of a 0.500M solution? Molarity = Mass / Molar Mass Liters of Solution 0.500 = mass / 101.11 2.0 (0.500)(2.0) = Mass 101.11 Mass = (0.500)(2.0)(101.11) Mass = 101.11 grams

10
Example 5 To what volume should 5.0grams of KCl be diluted to in order to prepare a 0.25M solution? Molarity = Mass / Molar Mass Liters of Solution 0.25 = 5.0 / 74.55 Volume V(0.25) = 5.0/74.55 V = 0.0671 0.25 V= 0.268 Liters = 268 mLs

Similar presentations

© 2021 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