click below
click below
Normal Size Small Size show me how
7F Chemical Reaction
Revision on chemical reaction
| Question | Answer |
|---|---|
| What is a chemical reaction? | It is when chemicals join or break apart to form new chemicals. |
| What is a physical change? | When a substance has changed it's form but no new substances were made. |
| What is the difference between a reversible and irreversible change? | Reversible: Can return to its orginal form. Irreversible: Cannot change back. |
| What is the word equation for magnesium reacting with oxygen. | Magnesium + Oxygen = Magnesium Oxide |
| What causes iron and steel to rust? | From the oxygen and water from the air and rain. |
| What causes acid rain? | The nitric or sulphuric acid in it. |
| What are reactants? | They are the chemicals that react together and make new substances. |
| What makes dry ice? | The solid state of carbon dioxide. |
| What happens when CO2 + Ca(OH)2? | The limewater will turn cloudy. |
| What are the 3 things in the fire triangle? | Fuel, heat and oxygen. |
| What is usually used to put out fires? | Fire extinguishers or water. |
| What is another word for burning? | Combustion. |
| Fuel + Oxygen = ? | Carbon Dioxide + Water |
| If we leave a candle burning in a beaker, will it stop burning and why? | It will go out because it uses up all of the oxygen and the carbon dioxide will put it out. |
| What makes a chemical reaction become an explosion? | A large amount of gas is formed, a lot of heat is released, plenty of oxygen is available. |
| What is Nitroglycerine? | It is a very sensitive explosion that can explode by just a liitle bit of energy. |
| What is the best type of extinguisher for putting out wood fires? | Water. |
| What naturally stops forest fires? | Fire breaks. |
| About how much percent is the air oxygen? | 20%. |
| What is in water? | Hydrogen and oxygen. |
| What is in carbon dioxide? | Carbon and oxygen. |