Acids and Bases

Acids and Bases

Acids

• Acids tend to have a sour taste

• Acids react strongly with metals to produce hydrogen

• Acids are corrosive, which means that they can eat away at the surfaces of different materials.

• Acids in your everyday lives include lemon juice, vinegar, hydrochloric acid in your stomach and ascorbic acid (Vitamin C).

Bases

• Bases tend to taste bitter and are usually slimy or slippery.

• Another word for base is alkali.

• Like acids, bases are corrosive. When talking about bases however, we instead use the word caustic.

• Bases include soap, baking soda, antacids and bleach.

Categorize

Options (10)

Sour

Corrosive

Lemon Juice

Bitter

Slimy/Slippery

Caustic

Bleach

Vinegar

Baking Soda

Alkali

Organize these properties into the right categories

Acid

Base

pH Scale

• The pH scale measures how acidic or basic a substance is.

• pH stands for 'Potential of hydrogen'. It measures the concentration of hydrogen ions.

• The higher the concentration of hydrogen ions, the lower the pH.

• Acids have more hydrogen ions (H⁺).

• Bases have more hydroxide ions (OH^-).

pH Scale

• Substances with a pH below 7 are considered acidic.

• Substances with a pH above 7 are considered basic.

• Substances with a pH of 7 are considered neutral.

Labelling

Have a guess at the pH of these household items.

Drag labels to their correct position on the image

Vinegar

Lemon Juice

Baking Soda

Bleach

Strength of Acids

Strength of Bases

Match

Match the following beakers with the correct acid or base.

Acids have more H⁺

Bases have more OH^-

Strong Base

Strong Acid

Weak Base

Weak Acid

• Strong Base

• Strong Acid

• Weak Base

• Weak Acid

• A small amount of acid or base dissolved in a large volume of water.

• To dilute a solution, water is added to the substance.

• Diluting a solution makes it more neutral.
  

Concentrated Solutions

Concentrated and Dilute Solutions

Dilute Solutions

• A large amount of acid or base dissolved in a small volume of water.

• To make a concentrated solution, more acid or base can be added.
  

Multiple Select

Josie has a solution of hydrochloric acid. She decides to add more water to the solution. What happens to the solution? Select two of the following answers.

• The solution becomes more dilute

• The solution becomes more concentrated

• The solution becomes less acidic

• The solution becomes more acidic

Indicators

• Indicators are chemicals that change colour depending on the pH of their environment.

• We can use these indicators to determine the pH of solution

• There are several different types of indicators

  • Red cabbage indicator

  • Universal indicator

  • Litmus paper

Neutralisation Reactions

• When acids are added to a base or vice versa, the pH becomes neutral. This is known as a neutralisation reaction.

• Neutralisation reactions produce a salt (metal and non-metal bonded together), and water.

Neutralisation Reaction Example

• When you brush your teeth, the bases inside the toothpaste help to neutralise the acids produced by plaque on your teeth.

Drag and Drop

Heartburn occurs when acid from your stomach works its way up your oesophagus. Antacids like Quick-eze contain ​

Placeholder

which help ​

Placeholder

your stomach acid, and relieve the heartburn.

Drag these tiles and drop them in the correct blank above

bases

neutralise

acids

acidify

Multiple Choice

Mr Theobald was very clumsy and spilled a large amount of concentrated hydrochloric acid on the ground. Which chemical should he use to clean up the spill?

• Sulfuric Acid - pH 1

• Lemon Juice - pH 2.8

• Milk - pH 6.5

• Baking Soda - pH 8.8