Learning Outcomes Through experimentation, I can identify indicators of chemical reactions having occurred. I can identify the difference between a chemical change and a physical change

Concept Card Scrambled egg has only one ingredient so it must be an element. Perhaps its a mixture of compounds. You mix it up with a spoon so it must be a mixture. You cant separate it so it must be a compound.

Chemical Reactions During a chemical reaction a new substance is formed. During a chemical reaction one or more of the following may also occur. an energy change a gas could be given off a colour change Try two experiments for yourself

Experiment One Collect a piece of magnesium and place it between your tongs. Hold the piece of magnesium in the Bunsen flame.

Quarter fill one test tube with lead nitrate solution. Quarter fill another test tube with potassium iodide solution. Mix the two solutions, by pouring one solution into the other and observe what happens. Experiment Two

Questions on Experiments Q1.What three signs showed that chemical reaction had taken place during experiment one? Q2.What two signs showed that a chemical reactionhad taken place during experiment two.

Physical Changes Dont mix up chemical reactions with a physical change. Physical changes happen without making new substances.

Example of Physical Change - 1 Ice melts to produce liquid water. This is not a chemical reaction because no new substances were made. Only the state of the substance changed i.e. solid liquid. You could get the ice back by freezing the water.

Example of Physical Change - 2 Salt dissolves in water to form a salt solution. This is not a chemical reaction because no new substances Were made. We could get the salt back by Evaporating the water. Try it in the watch glass!

Physical or Chemical Changes? Q1.Is boiling water a physical or chemical change? Explain your answer. Q2.Is melting aluminium a physical or chemical change? Explain your answer. Q3.Is dissolving sugar in your tea aphysical or chemical change? Explain your answer. Q4.Is burning a candle a physical or chemical change? Explain your answer.

Physical & Chemical Changes? Your teacher may let you try the Card Sort For physical or chemical changes? Arrange yourselves into groups of 2 or 3. Look at the cards and sort them into piles of physical changes and chemical changes.

RSC Physical or Chemical Change Collect the RSC work card and complete in your jotters

Summary During a chemical reaction a new substance is formed. During a physical change a new substance is not formed. Examples of physical changes include when a substance melts or dissolves. During a chemical reaction one or more of the following may also occur. An energy change i.e. heat given out A gas could be released A colour change