Year 10 Homework: a bit more on decomposition reactions and word equations
Here are some notes you need for this part of the topic. Copy them into your book ready for tomorrow. Look at the short video as well
Copper carbonate decomposes when heated to form copper oxide and carbon dioxide. Instead of writing this information as a sentence chemists use something called a word equation to tell the same story. On the left hand side of the word equation we write down the substances that are reacting. On the right hand side we write down substances that are produced, the products.
Copper carbonate heat —> copper oxide + carbon dioxide
Copy down and complete these equations:
Zinc carbonate heat—>
Magnesium carbonate heat —>
Calcium carbonate heat —>
Decomposition reactions often need heat to make them happen. Other decomposition reactions occur when a catalyst is present. Hydrogen peroxide is a water molecule with an extra oxygen atom. Manganese dioxide is a catalyst that helps it to decompose into water and oxygen molecules.
Hydrogen peroxide —-catalyst—-> water + oxygen
Have a look at the short video of water and hydrogen peroxide molecules. If the chemical formula for water is H2O what is the chemical formula for hydrogen peroxide?
Now look at some oxygen gas being made.