Download presentation

1
Concentration

2
**CALCULATING CONCENTRATION OF SOLUTIONS**

1. Mass Percent = (mass of solute/mass of solution)100 2. Parts per million = (mass of solute/mass of solution)106 3. Mass/volume percent = (mass of solute/mL solution)100 4. Volume percent = (mL solute / mL solution)100 5. Molarity = n/V = moles solute / L solution 6. Molality = moles of solute / kg solvent

3
**CALCULATING CONCENTRATION OF SOLUTIONS**

What is the mass percent of a solution made by adding 25.0 g of KCl to mL of water? What is the concentration of a solution made by mixing 25.0 g of KCl in (a) mL and (b) L of water in ppm?

4
**The following slides are extra worked out examples.**

5
**CALCULATING CONCENTRATION OF SOLUTIONS**

How many grams of a solution that is 32.7% by mass NaCl would contain 45.0 g of NaCl? Mass % = (mass of solute /mass of solution) 100 32.7 % = (45.0 g / x )100 x = 45.0 g / 0.327 x = mass of solution = 138 g

6
**CALCULATING CONCENTRATION OF SOLUTIONS**

How much solute is present in mL of a 14.7% (mass/volume) HCl solution? Mass/volume % = (masssolute/volumesolution) 100 14.7 % = (x / mL )100 x = (756.1 mL) x = mass of solute = 111g

7
**CALCULATING CONCENTRATION OF SOLUTIONS**

How many grams of LiF are in 500 mL of a solution that is 18.4% by mass and has a density of g/mL? Masssolution = densitysolution (Volumesolution) = g/mL (500 mL) = g solution Mass% = (masssolute/masssolution) 100 18.4 % = (x / g )100 x = (598.5 g) x = mass of solute = 110 g

8
**CALCULATING CONCENTRATION OF SOLUTIONS**

A 350 mL sample of drinking water was analyzed and found to contain g of sulfate salts. Calculate the concentration of sulfate salts in this water sample? Masswater = densitywater (Volumewater) = 1.00 g/mL (350 mL) = 350 g solution ppm = (masssolute/masssolution) 106 ppm = (0.0046g / 350 g ) 106 ppm = 13 ppm Use ppm for trace amounts of solute.

9
**CALCULATING CONCENTRATION OF SOLUTIONS**

Calculate the molality of a solution composed of 53.0 g of KOH in 500 mL of water. First calculate the moles of solute: n = 53.0 g (1 mol / 56 g) = mol solute Next, m = moles of solute / kg solvent m = (0.946 mol / kg ) m = 1.89 molal solution

10
**PRACTICE PROBLEMS #36 calculating the CONCENTRATION OF SOLUTIONS**

___1. How many grams of a 45.0 % Mg(OH)2 solution can be made from 7.00 g of solid Mg(OH)2? ___2. How many kilograms of a 6.8% KC2H3O2 solution will contain 5.3 moles of KC2H3O2? ___3. How many grams of KOH are needed to make mL of a solution that is to contain 6.70 mg/mL of potassium ion? ___4. If g of a 25.0 % sucrose solution was prepared, how many grams of a 5.00% solution of sucrose would contain the same amount of sugar? ___5. How many grams of solution, 10.0% KOH by mass, are required to neutralize 25.0 mL of a 2.00 M HCl solution if the moles of HCl is equal to the moles of KOH? 15.6 g 7.6 kg 2.41 g 673 g 28.0 g

11
**Group study problem #36 calculating the CONCENTRATION OF SOLUTIONS**

___1 How many grams of a solution, that is 76.3% by mass KBr, would contain g of KBr? ___2. What is the ppm and molality of a solution containing 75.0 g of ethylene glycol, C2H6O2, in g of water? ___3. How many grams of CuSO4 are needed to make mL of a solution that contains 10.5 mg/mL of Cu2+ ion? Calculate the molarity of the resulting solution. ___4. Automobile battery acid is 38% H2SO4 and has a density of 1.29 g/mL. Calculate the molality of this solution. ___5. If 27.0 g of LiBr are dissolved in 50.0 g of water, the percent of LiBr by mass is ___6. If 15.0 g of KNO3 is added to 75g of water, what is the mass percent of KNO3 in the solution?

Similar presentations

© 2020 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