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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. |