Question | Answer |
What is physical a reaction? | When you melt ice it turns into water, the ice has changed from a solid to a liquid but it is still the same substance |
What is a chemical reaction? | Chemical reactions produce new substances. Like a change in colour, a gas is given off, an energy change (heat) |
What is the one product of the reaction between limestone and acids? | The one product of reaction is carbon dioxide |
What is the word equation to magnesium and oxygen? | The word equation is
magnesium+oxygen---->magnesium oxide |
What percentage of the air is oxygen? | Air is about 20% oxygen |
What are the 3 things needed to complete a fire triangle? | For a fire to burn there are 3 things needed:
1) A substance that burns (fuel)
2) Energy to start the fire (usually heat)
3) Oxygen (usually from the air) |
What is the word equation for methane and oxygen and what is the anwser? | The complete word equation and anwser is:
methane+oxygen---->carbon dioxide+water |
What is another name for burning? | Burning is also called combustion. We can summarise what happens when we burn a fuel by writing a word equation |
What happens when you cool down carbon dioxide down to 80degrees celsius? | It creates dry ice which is solid carbon dioxide |
What is a fuel? | A fuel is a substance which contains energy that can be trasnformed into heat energy |
Why is rainwater corrosive and acidic? | Rainwater is corrosive as sometimes the rainwater can be polluted with nitric or sulphuric acids. This acidrain will attack the iron and make it corrode more quickly |
How do we make sure that gas is carbon dioxide? | To be sure that gas is carbon dioxide we use the limewater test. If carbon dioxide is mixed with limewater, it will go milky. With other gases the limewater always stays clear |
What is the reaction to a substance burned? | When a substance burns, it reacts with the oxygen in the air. |
What happens to metals that are used in fireworks when they go off? | The metals in the fireworks will burn in the oxygen with a particular colour to form oxides |
What is the name of any chemical that is made of only carbon and hydrogen? | Any chemical that is made of only carbon and hydrogen is called a hydrocarbon |
What gets realeased from a chemical reaction explosion? | The remains would be a certain amount of gas,a lot of heat is released and plenty of oxygen is available |
What is wax made up of? | Wax is a substance that contains a lot of carbon joined joined to hydrogen |
What is natural gas? | Natural gas is another example of fuel. Natural gas is mainly methane |
What is carbon monoxide? | Carbon monoxide is a very poisonous gas that is tasteless and doesn't smell. |
What is the word equation to methane and oxygen? | The word equation is:
methane+oxygen---->carbon mioxide+water |
How can we test for carbon monoxide? | We can test for carbon monoxide by placing carbon monoxide detectors near gas appliances |
What are explosives? | Explosives are chemicals that react very violently. |
Why is water used to put of the heat from a buring object? | water is often used to put fires out;as it takes away the heat |
Name one reason why putting fires out with water is also a bad thing to do? | The water should never be used when oil is buring as the water sinks through the oil and the heat turns the water into a stream. The stream rised very quickly to the surface of the oil, pushing the burning oil out this makes the fire spread out more |
How is carbon dioxide produced? | Carbon dioxide is produced with the oxygen in the air |
Why are fire extingushers used when tehre is a fire? | They stop oxygen from getting ot the fuel |
When you cook food is it true that the cooker causes chemical changes? | Yes, the cookers does cause chemical changes, if you turn the heat off, the food stops cooking, the chemical reaction stops |
Does iron fillings react with sulphuric acid? | Yes they both react as they are reactants. Eventually there will be no iron left, it will have turned into a new substance |
What makes limewater go milky? | Carbon dioxide makes the limewater milky as it is reacting with the water |
Why should water never be used on an electrical fire? | It will create a serious electrical shock. The electricty should be turned off at the mains, and a dry fire extingusher used. |