5 Indicators of a Chemical Change From this

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5 Indicators of a Chemical Change From this lesson you will be able to

5 Indicators of a Chemical Change From this lesson you will be able to determine if a chemical change has taken place (IPC 8 A & Chem 4 A).

What is a Chemical Change? • It is a change that occurs when a

What is a Chemical Change? • It is a change that occurs when a substance changes composition by forming one or more new substances. • The new substances/products that are formed have a different chemical formula from the original substances/reactants at the beginning.

What did you observe? Bubbles Mg + 2 HCl Mg. Cl 2 + H

What did you observe? Bubbles Mg + 2 HCl Mg. Cl 2 + H 2 Production of Gas is an indicator of a Chemical Change. This reaction is very similar to the reactions that take place in the digestive track when Hydrochloric Acid (HCl) in your stomach aids in the digestive process. Digestion is a chemical change.

What did you observe? Light 2 Mg + O 2 2 Mg. O Formation

What did you observe? Light 2 Mg + O 2 2 Mg. O Formation of Light is an indicator of a Chemical Change. This is the same reaction that is used to make fireworks and sparklers.

What did you observe? Yellow Color Change and a Precipitate (insoluble solid) Pb(NO 3)2

What did you observe? Yellow Color Change and a Precipitate (insoluble solid) Pb(NO 3)2 + 2 KI Pb. I 2 + 2 KNO 3 Permanent Color Change and Formation of a Precipitate are two indicators of a Chemical Change. Reactions like these are used in water treatment plants to form precipitates that help remove calcium, magnesium, iron, and manganese ions from the water.

What did you observe? A Temperature Change Ba(OH)2. 8 H 2 O + 2

What did you observe? A Temperature Change Ba(OH)2. 8 H 2 O + 2 NH 4 SCN --> Ba(SCN)2 + 10 H 2 O + 2 NH 3 Temperature Change is an indicator of a Chemical Change. Endothermic Reactions = absorb heat and feel cold Exothermic Reactions = release heat and feel hot

Let’s Review The 5 Indicators of a Chemical Change are… 1. Production of Gas

Let’s Review The 5 Indicators of a Chemical Change are… 1. Production of Gas 2. Production of Light 3. Permanent Color Change 4. Formation of a Precipitate 5. Temperature Change

Test Your Knowledge • Go to the Live Chem website below: • http: //www.

Test Your Knowledge • Go to the Live Chem website below: • http: //www. chem. ox. ac. uk/vrchemistry/Live. Chem/transitionmetals_content. html • While in the Virtual Chemistry Lab, perform the following 5 experiments and record whether they demonstrate a chemical change. Then choose 5 other experimental mixes of your own and record whether they demonstrate a chemical change. Use the 5 Indicators of a Chemical Change to support your findings for all 10 experiments conducted. • Click on the next slide for the Lab Write-up.