1.2 - Acids and Bases

Question 1

Define pH

Answer 1

A measure of acidity. Indicates the concentration of hydrogen ions in a solution (potential of hydrogen)

Question 2

Define acids

Answer 2

A compound that dissolves in water to form a solution with a pH lower than 7
- Ex. lemon juice, vinegar

Question 3

Define base

Answer 3

A compound that dissolves in water to form a solution with a pH higher than 7
- Ex. hair conditioner, antacid

Question 4

What is the pH scale?

Answer 4

• Measures acidity. Solutions will have a pH in the range of 0-14
• Closer to 0 = More acidic
• Closer to 14 = More basic

Question 5

What is a neutral substance?

Answer 5

A substance with pH 7 that is neither acidic nor basic

Question 6

How can pH be measured?

Answer 6

• PH can be measured using a pH meter
• Acid-base indicators are substances that change colours in solutions:
• Blue litmus paper turns red in an acid and red litmus paper turns blue in a base
• A universal indicator will change a different colour for each value on the pH scale

Question 7

What is neutralization?

Answer 7

• A reaction between an acid and a base that produces a water and a salt
• Acid + Base → Salt + Water
• HCl(aq) + NaOH(aq) → NaCl(s) + H2O(l)
  
  • Ex. Antacids

Question 8

How does acid rain form?

Answer 8

• Acid rain forms when industrial processes and fuel combustion release chemicals into the air that combine with water to form acids.
  
  • Sulfur dioxide becomes sulfuric acid
  • Carbon dioxide becomes carbonic acid
• Nitrogen oxides become nitric acid
• The droplets fall as acid rain, harming the environment
• Acidic lakes are sometimes neutralized with lime-water (calcium hydroxide mixed with water). The reaction produces calcium sulfate (a salt) and water.
  
  • Ca(OH)2(aq) + H2SO4(aq) → CaSO4(s) + 2H2O(l)