What is shown in a chemical reaction?
- Bubbles are produced ( gas )
- Heat ( exothermic / endothermic )
- Colour change
- a solid is made
What is a Reactant?
Reactants are the starting materials used in the experimant
What is a Product?
The products are what are made in the reaction
Exothermic and Endothermic Reaction
- An exothermic reaction is a reaction where heat is given out
- An Endothermic reaction is a reasion which takes in heat
Space Filler Diagram
- no atoms are created or destroyed just rearranged
- new substances are formed
- when compounds are formed, elements are chemically joined together
- the Metal looses electrons and becomes a positive ion
- the non-metal gains electrons and becomes a negative ion
- an ion is an atom with a charge
Acid and Metals
acid + metal --> salt + hydrogen
the first name of the salt is always the name of the metal
the surname of the salt depends on the name of the acid
Testing for hydrogen
Method - put a lit splint into hydrogen gas
Result - if hydrogen is present, you'd hear a squeaky pop
*Making a salt
1. Excess metal is added to the dilute acid, this is to make sure that all the acid is used up. Then gently heat the mixture to speed up the reaction.
2. Filter the mixture using filter paper and a filter funnel, this is to remove the unreacted metal. ( filtraction )
3. The solution left is then placed in an evaporating basin and placed by a window at room temperature to evaporate. A crystal is formed in the evaporating basin.
Acid and Alkali
acid + alkali --> salt + water
this is known as neutralisation
acid and metal oxide
metal oxide + acid --> salt + water
acid and metal carbonate
acid + metal carbonate --> salt + water + carbon dioxide
Testing for Carbon Dioxide
method - Gas is passed through lime water
Result - the limewater goes from a colourless solution to a milky colour if carbon dioxide is present