Lemonade-Ed - Lesson: Acids & Bases

Lesson Plan: Acids & Bases

Navigate the knowledge tree: 🌿 Chemistry ➡ Chemical Changes ➡ Ions

Hei Mahi (Do Now)

Do Now in your Exercise Book

1. Write everything you know about 'acids'

2. Write everything you know about 'bases'

For example: What are they, give examples, what do they taste / feel like, what are they used for, what ions are present?

Hei Mahi (Do Now) ANSWERS

Do Now on your Whiteboard

Acids are substances that release acid particles (H⁺ ions) in water. Some acids are used for cooking and taste sour, such as vinegar and lemon juice. But some acids are extremely harmful to the body but useful in technology, such as sulfuric acid found in batteries.

Bases are substances that remove acid particles from a solution. If the base dissolves in water, it is called an 'alkali'. Bases are slippery and are often found in cleaning products. Bases are also used to cancel out (or neutralise acids). Examples of bases are metal hydroxides, metal oxides, metal carbonates and metal hydrogen carbonates.

Knowledge: Acids

In water, acids break up (dissociate) into hydrogen ions (H⁺) and another negative ion.

Knowledge: Types of Acids - Mineral Acids (Strong)

Mineral acids are manufactured from minerals. The acids you use in the laboratory are mostly mineral acids. Some examples are:

Hydrochloric acid (HCl) is a mineral acid commonly found in the laboratory and in the stomach.

Sulfuric acid (H₂SO₄) is a mineral acid commonly found in the laboratory and in car batteries.

Nitric acid (HNO₃) is a mineral acid commonly found in the laboratory and in producing nitrogen-based fertilisers.

Phosphoric acid (H₃PO₄) is a mineral acid commonly found in the laboratory and in producing fertilisers.

Knowledge: Types of Acids - Organic Acids (Weak)

Organic acids are often found in nature and all contain the element carbon. Some examples are:

Acetic acid (CH₃COOH) is an organic acid found in vinegar. Link to molecular structure.

Citric acid (C₆H₈O₇) is an organic acid found in citrus fruits like oranges and lemons.

Tartaric acid (C₄H₆O₆) is an orgaic acid commonly found in baking ingredients.

Lactic acid (C₃H₆O₃) is an organic acid commonly found in milk products (e.g. yogurt) and fermented food (e.g. kimchi, sauerkraut).

A strong acid like hydrochloric acid (HCl) fully dissociates (breaks up) and releases many hydrogen ions. A weak acid like acetic acid (CH₃COOH) only partially dissociates and releases few hydrogen ions.

Activity: sciPad

Complete sciPad:

Pages 51 - Acids

Knowledge: Bases

Bases are acid opposites
bases will remove hydrogen ions (H⁺) from a solution.
Metal hydroxides, metal oxides, metal carbonates and metal hydrogen carbonates are all bases and will remove H⁺ ions from solution.
Soluble bases are called alkalis.

Sodium hydroxide (NaOH) is an alkali base commonly found in oven cleaners.

Ammonium hydroxide (NH₄OH) is an alkali base commonly found in household cleaners.

Magnesium hydroxide (Mg(OH)₂) is an alkali base that is commonly found in indigestion tablets.

Calcium hydroxide (Ca(OH)₂) is commonly found in white wash. It is NOT an alkali and is not soluble in water.

Activity: sciPad

Complete sciPad:

Pages 52 - Bases

Homework

Complete sciPad pages 51-53.

Exit Routine

Let's Pack Up Together

Return all materials to the correct container.

Scan your surroundings for rubbish and put in the bin.

Put your brown paper bag back into the correct grey tray.

Quietly stand behind your chair. Wait for the Karakia leader to begin.