Review Acids and Bases

Acids, Bases and pH Overview

Ms. Bev Taylor

Multiple Choice

Many cleaning solutions are bases. Which of the following is a property of most bases?

• feels slippery
• white color
• can only be liquid
• tastes sour

Multiple Choice

Many cleaning solutions are bases. Which of the following is a property of most bases?

• feels slippery
• white color
• can only be liquid
• tastes sour

Multiple Choice

Soap is a weak base.  What is true about the taste of bases?

• they taste sour
• they taste sweet
• they taste bitter
• they taste salty

Multiple Choice

Soap is a weak base.  What is true about the taste of bases?

• they taste sour
• they taste sweet
• they taste bitter
• they taste salty

Multiple Choice

When dissolved in water, bases produce:

• acids
• salts
• hydrogen ions
• hydroxide ions

Multiple Choice

When dissolved in water, bases produce:

• acids
• salts
• hydrogen ions
• hydroxide ions

Multiple Choice

Which of these solutions is an acid?

• Dish Soap: pH of 12
• Tomato Soup: pH of 4
• Baking Soda: pH of 9
• Drain Cleaner: pH of 14

Multiple Choice

Which of these solutions is an acid?

• Dish Soap: pH of 12
• Tomato Soup: pH of 4
• Baking Soda: pH of 9
• Drain Cleaner: pH of 14

Multiple Choice

Which of the following word pairs correctly completes the sentence below?

_______ are corrosive substances characterized as having a strong smell, a sour taste, and a _______.

• acid pH less than 7

• acid pH greater than 7

• base pH less than 7

• base pH greater than 7

Multiple Choice

Which of the following word pairs correctly completes the sentence below?

_______ are corrosive substances characterized as having a strong smell, a sour taste, and a _______.

• acid pH less than 7

• acid pH greater than 7

• base pH less than 7

• base pH greater than 7

Multiple Choice

What would be considered the weakest base?

• 8

• 7.8

• 11.6

• 14

Multiple Choice

What would be considered the weakest base?

• 8

• 7.8

• 11.6

• 14

Multiple Choice

Stronger acids have a pH closer to...

• 7

• 14

• 0

• 9

Multiple Choice

Stronger acids have a pH closer to...

• 7

• 14

• 0

• 9

Multiple Choice

Weaker bases have a pH closer to...

• 8

• 14

• 0

• 4

Multiple Choice

Weaker bases have a pH closer to...

• 8

• 14

• 0

• 4

Multiple Choice

Which of the following is true about acids and bases?

• The lower the pH #, the stronger the acid

• the higher the pH #, the stronger the acid

• The lower the pH #, the more neutral the acid

• The higher the pH #, the weaker the base

Open Ended

What does a chemical equation tell you?

Multiple Choice

Can we use mole ratios to calculate how much product is produced from a known amount of reactant?

• Yes

• No

Multiple Choice

What is Avogadro's Number?

• 6.0 x10^23

• 6.0x10^24

• 1023 x 10^6

• 8675309

Concentration

• measure of the amount of solute in a given amount of solvent or solution

• 2 ways to measure

• molarity- mol/L of solution

• molality- mol/ g of solvent

Molarity

• number of moles of solute in one liter of solution

• How to make

• 1. Determine desired molarity i.e. .5 M, 1 M

• 2. determine the mass needed by converting mol to gram

• 3. dissolve in less solvent than 1 L

• 4. Bring total solution to 1 L

When calculating Molarity remember:

n of solute / L solution

If you did not get the correct answer on that problem, take a look at the solution here.

Do you see what you might have done wrong?

We are not always dealing with solids when we make solutions in the chemistry lab.

Sometime we have liquid reagents.

Liquid Reagents

When we are mixing chemicals that involve only liquids, we must use this equation to solve for molarity or volume.

Example: I have concentrated HCl in the storage room

• Concentrated HCl is 12 M

• I want to use 0.5 M HCl in a lab demo

• I must use the equation M1V1=M2V2 to mix the correct amount of HCl for lab

12M HCl is what I have, but I only need 250 mL of 0.5M HCl

I must first look at what I know....

I want 250 mL of 0.5 M HCl. (V1=250 mL and M1=0.5 M)

I have 12 M HCl (V2=12 M)

I need to solve for the V2

M1V1=M2V2

(.5M)(250mL) = (12M)(V2)

When I solve this equation, I get 10.4 mL for V2

This means that I need 10.4 mL of 12 M HCl.

I will take 10.4 mL of 12M HCl and dilute it to 250 mL.

This will make 250 mL of a 0.5M HCl solution.