Multi-word fill quiz Q4 on "Simple Chemical Reactions" © Doc Brown's KS3 chemistry

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   carbon      dioxide      energy      flammable      fuel      gas      hazard      hydrogen      light      natural      oxygen      petrol      reaction      water      word   
hws4.gif1. This warning symbol means the substance is very . A substance like should be labelled with this sign.
2a. When substances burn they react with the gas and the reaction is fast releasing lots of heat .
2b. The release of heat is a sign that a chemical is happening. Energy is often given out as too in combustion reactions.
3a. Substances that give out heat on burning can be used as a . Most fuels contain the chemical elements (C) and (H).
3b. Methane is fuel which we get from under the North Sea and is also known as .
4. Chemical reactions can be represented by equations, a sort of shorthand. When the fuel methane burns in air, the word equation is ...
methane + oxygen ==> +