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.
At the conclusion of your last lesson you knew more about the atom than Ernest Rutherford, apologies 1st Baron Rutherford of Nelson at the height of his career. The most fascinating thing about atoms is their size.
they are tiny compared to us
the nucleus of an atom is tiny compared to the rest of the atom
If you pumped up the nucleus of the smallest atom hydrogen to the size of a soccer ball and placed it on the centre circle of field at Rutherfield College gthe electron would be the size of a pea and you would find it somewhere around the sky tower in central Auckland!
Have a look at the video comparing the size of atoms to blueberries
The magnesium atoms in a piece of magnesium metal can be made to react chemically by either heating them in a bunsen flame or dropping them into an acid. (it didn’t matter whether it was dilute sulphuric acid or hydrochloric acid)
The reaction with acid produced a lighter than air gas that exploded with a pop when it was lit. Can you remember which gas it was?
Chemistry has its own language with words and sentences.
To a chemist the words are chemical formulae. When chemical formulae are joined together in a sentence we call this a chemical equation.
Hydrogen and oxygen mixtures explode when lit. In a test tube this explosion is heard as a “pop”. We call the test for hydrogen “the pop test”
The space shuttle is launched into space with three main engines. Each engine produces 1.8 Meganewtons of thrust. The engines are powered by liquid hydrogen and oxygen fuel stored in the large central rust coloured tank.
The space shuttle is blasted into space on the back of a mega “pop test” The two tanks on either side of the shuttle are solid fuel boosters.
Hydrogen molecules and oxygen molecules react with each other to form water molecules. A chemist rewrites this sentence as a word equation
hydrogen + oxygen —–> water
Chemists use chemical formulae instead of words. Finally chemists need to count the numbers of atoms involved. We need to have the same numbers of atoms after the reaction that we had at the start.
When we do this we end up with a fully balanced chemical equation. As far as NCEA level 1 is concerned here are the steps.
word equation…..achievement
with chemical formulae……merit
a fully balanced chemical equation…..excellence
Check out the video to see how we get a fully balanced equation for the “pop test”
try balancing the equations that describe metals reacting with acids.
