We have used word equations to produce fully balanced chemical equations in three steps. For a little more information on this process have a look at this post about the space shuttle being blasted into orbit on the back of a huge pop test.
the basic word equations we use are:
acid + base —–> salt + water
acid + metal —–> salt + hydrogen
Acid + carbonate —–> salt + carbon dioxide + water
Use these word equations to answer the questions below.
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
Write in the date followed by the heading Decomposition Reactions: now copy in the rest of your notes
•Decomposition reactions occur when a large molecule is broken down into two or more simpler substances.
•Some molecules are so unstable they literally fall apart (nitrogen triodide, NI3)
Other substances, many carbonates for instance require heat before they break down into simpler molecules. Hydrogen peroxide is another chemical which is not very stable and undergoes a decomposition reaction when it is treated with a catalyst.
Heating carbonates:
•Carbonates other than sodium and potassium decompose on heating.
•Copper carbonate is a green powder
•When it is heated strongly it turns to a black powder.
•This black powder is copper oxide.
•Copper carbonate has the chemical formula CuCO3
•Copper oxide has the chemical formula CuO
•As well as the black powder a gas that turns limewater milky is also produced. This is carbon dioxide, CO2 .
