Chapter 4Solubility Rules, Solutions, Dilutions

General Chemistry I Dr. Stone

8 Solubility Rules1. All Alkali Earth metal ionic compounds are soluble.2. All compounds with ammonia ions are soluble3. All hydrogen carbonates, perchlorates, chlorates, nitrates and acetates are soluble.

4. Compounds with chloride, bromide and iodide are soluble except with Ag+, Cu+, Hg2+2 and Pb+25. Compounds with sulfate are soluble except with Ca+2, Ba+2, Sr+2, Pb+2 and Hg2+2

6. All hydroxides are insoluble, except with Ca+2, Ba+2, and Sr+2

7. All sulfides are insoluble except with Ca+2, Ba+2 and Sr+2

8. Everything thing else is insoluble.

Is there an alkali earth cation or ammonium ion?

Yes

Soluble

No

Is there HCO3-, ClO4-, ClO3-, NO3-, or C2H3O2-?

Yes No

Soluble

Is there SO4-2

Is there Cl-, Br-, I- ?

Yes No

Is there Ag+, Cu+,Pb+2, Hg2+2?

Yes No

Insoluble

Soluble

Yes No

Is there Ca+2, Ba+2, Sr+2 , Pb+2, Hg2+2?

Yes No

Insoluble Soluble

Is there OH- or S-2?

Yes No

Is there Ca+2, Ba+2, Sr+2?

Yes No

Insoluble

Soluble

Insoluble

Solutions• Solute = smaller amount of something that is dissolved

in a solution• Solvent = larger amount of something in the solution• Water is a common solvent

• % solutions can be • w/w (g solute/100 g solution) • w/v (g solute/100 mL solution) • v/v (mL solute/100 mL solution)

• Molarity = moles solute/L solution

Solutions• Parts per million = 1 g in 1 x 106 g of water

• 1 x 106 g of water = 1 x 106 mL of water

• 1 x 106 mL = 1000 L

• 1g x 1000 mg = 1 mg 1000 L g L

• Parts per billion = 1 g in 1 x 109 g of water

• 1 x 109 g of water = 1 x 109 mL of water

• 1 x 109 mL = 1 x 106 L

• 1g x 1 x 106 ug = 1 ug 1 x 106 L g L

Dilution of SolutionsAdding solvent decreases the concentration of the solution. The moles stay the same, but the molarity decreases.

Molarity = moles/volume(L)

Same moles, more volume = less molarity

1. Find the moles: Molarity x volume(L) = moles

2. Divide the moles by the new volume(L) = new Molarity

What is the molarity of a solution that is made by diluting 10.0 mL of 0.2M sodium hydroxide to a total volume of 50 mL?

1. 10 mL x 1 L x 0.2 M = 2 x 10-3 moles 1000mL2. 2 x 10-3 moles x 1000 mL = 4 x 10-2 M 50 mL L

DilutionsWhat is the molarity of a solution that is made by diluting 25.00 mL of 3.00M hydrochloric acid (HCl) to 500.0 mL?

A. 1.5 x 10-1M

B. 6.66 M

C. 6 x 101M

D. 4.16 x 103M

E. None of these

DilutionsWhat is the molarity of a solution that is made by diluting 25.00 mL of 3.00M hydrochloric acid (HCl) to 500.0 mL?

A. 1.5 x 10-1M

B. 6.66 M

C. 6 x 101M

D. 4.16 x 103M

E. None of these