Matter

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Matter Energy
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Ammonium thiocyanate is mixed with barium
hydroxide.
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A drop of water is placed on a block of wood.
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The bottom of the beaker becomes cold enough to
freeze the water and stick to the wood.
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Ammonium thiocyanate is mixed with barium
hydroxide.
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The mixture is stirred. Water is one of the
products of the reaction.
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The reaction is endothermic. The temperature has
dropped.
http//jchemed.chem.wisc.edu/JCESoft/CCA/CCA3/STHT
M/ENDO2/ENDO2.HTM
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What kind of reaction was shown in the previous
two examples?

• Why?

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http//www.bbc.co.uk/schools/gcsebitesize/chemistr
y/chemicalreactions/2energychangesrev3.shtml
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Exothermic reactions Some reactions give out heat
energy. They are called exothermic reactions.
Magnesium gives out energy when it burns to make
magnesium oxide. Energy is also released when
fuels are burnt.
Both of these examples are oxidation reactions