Chemical reactions

The world arround us exists because chemical reactions have created the substances we can see, touch and smell. In this topic, you will learn how to identify physical and chemical changes. Scientists call chemical changes reactions and we will look at 5 types.

Task 2c: Make notes that:

• Define

  • chemical reaction

  • reactants

  • products

• List signs of a chemical reaction occurring

• Compare the properties of the reactants (sulphur and iron) and the products (iron sulphide) from the video

• Write word equations for the following reactions:

  • Carbon reacts with oxygen to produce carbon dioxide

  • Hydrogen reacts with oxygen to produce water

  • Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen

Task 3c: Make notes that:

• Define the law of conservation of mass

• If we have this reaction: A + B → C Calculate the following:

  • If we have 5g of A reacting with 10g of B, what is the mass of C?

  • If we have made 3.8g of C, and we started with 1.2g of A, what was the mass of B?

• Define a symbol equation and give an example

Task 4c: Make notes that:

• Describe how to test a gas to see if is oxygen

• Describe how to test a gas to see if it is hydrogen

• Describe how to test a gas to see if it is carbon dioxide

Task 5c: Make notes that:

• Define a chemical change and give an example

• Define a physical change and give an example

• Copy and complete this table by ticking whether the statement applies to chemical changes, physical changes or both.

• List the 5 different types of reaction with a description for each.

Task 7b: Based on the experiment described in the sides, answer the following:

• Give the independent variable

• Give the dependent variable

• List the control variables

• Draw a diagram of the apparatus

• Write a method for the experiment

• Use the example data in the slides to plot a graph (X axis = size of beaker, Y axis = Time taken for candle to go out)

• Describe the trend on the graph

• Explain the trend on the graph

Task 8c: Make notes that:

• Define thermal decomposition

• Define a metal carbonate

• Give the general word equation for thermal decomposition of metal carbonates

• Write a word equation for thermal decomposition of copper carbonate

• Write a symbol equation for the thermal decomposition of copper carbonate (CuCO3)

• Complete word and symbol equations for the thermal decomposition of:

  • Magnesium carbonate (MgCO3)

  • Zinc carbonate (ZnCO3)

  • Calcium carbonate (CaCO3)

• Compare combustion and thermal decomposition

Complete the quiz to make sure you understand this unit.