Indicators and Alkalis Flashcards
Define an indicator and give examples
A substance that changes colour in relation to the pH of another substance.
Examples:
Plant Dyes
Litmus Paper
Universal Indicator
Describe how to make red cabbage indicator
To make your own indicator, you will need:
Red cabbage
A kettle and water
Household substances to test, such as lemonade, vinegar, baking powder or toothpaste. These are your substance samples.
- Chop up the red cabbage into small pieces and place it in a mug.
- Add freshly boiled water from the kettle.
- Stir the cabbage and boiling water until a deep purple solution is made.
- Put drops of your substance sample onto a white plate and then add your red cabbage solution.
- Use the colour comparison chart to find the pH of your substances.
The pH scale and where on the scale I would find a weak
or strong acid or alkali
The pH scale is a logarithmic scale that measures the acidity or alkalinity (basicity) of a solution. The scale ranges from 0 to 14, with 7 being considered neutral. Here’s a breakdown of where you would find weak or strong acids and alkalis on the pH scale:
pH Scale:
0-6: Acidic range
7: Neutral
8-14: Alkaline (basic) range
Neutralisation Reactions, what are the reactants and
products
A neutralisation reaction is a chemical reaction between an acid and a base, resulting in the formation of water and a salt.
The general chemical equation for a neutralization reaction is:
acid + base → water + salt
In a chemical reaction, reactants are the substances that undergo a chemical change to form new substances. They are written on the left side of a chemical equation.
In a chemical reaction, products are the substances that are formed as a result of the chemical change. Products are written on the right side of a chemical equation.
Uses of neutralisation everyday such as farmers liming
soils and antacid tablets.
Neutralization reactions have several practical applications in everyday life. Here are two examples:
Farmers Liming Soils:
Farmers often use neutralization reactions to improve soil quality. Soils can become acidic due to factors such as rainfall, leaching of basic minerals, or the decomposition of organic matter.
Antacid Tablets:
Antacid tablets are commonly used to relieve indigestion and heartburn, which are often caused by an excess of stomach acid. These tablets typically contain compounds that undergo neutralization reactions with the acidic stomach contents. For example, many antacids contain aluminum hydroxide or magnesium hydroxide.
How to name salts using the acid for example HCL –
Hydrogen Chloride
Naming salts:
1. hydrochloric acid produces chloride salts.
1. nitric acid produces nitrate salts.
1. sulfuric acid produces sulfate salts.
All metal oxides are bases, some bases dissolve in water
to from hydroxides (Alkalis) for example calcium oxide
forms the alkali calcium hydroxide. True Or False?
True
Using the name of the base, how else can you name a salt?
When a base neutralises an acid you use the first name of
the base and it becomes the first name of the salt.
Copper oxide + sulphuric acid -> copper sulfate and water
Can Carbonates make salts?
Yes
All carbonates make CO2
when added to acids. Acid = carbonate – Salt + water and
CO2.
Do Metals react with acids to form salt and hydrogen?
Yes
Metal + acid – salt and hydrogen.
Define acid rain and describe how it is formed by the
burning of fossil fuel. List some of its effects.
Acid rain refers to precipitation, such as rain, snow, or fog, that has become acidic due to the presence of pollutants in the atmosphere.
Acid rain can harm aquatic ecosystems, leading to the acidification of lakes and rivers. This negatively affects fish and other aquatic life.
The test for CO2
Carbon dioxide reacts with calcium hydroxide solution to produce a white precipitate of calcium carbonate. Limewater. It turns milky in the presence of carbon dioxide.
Test for Hydrogen
Test for Hydrogen: Place a lighted splint in a test tube containing the gas. If the gas is hydrogen, there will be a squeaky pop.
