Is going grocery shopping the same thing as balancing chemical equations? Totally!!! Go into a supermarket now and get yourself – a bag of chips – a bottle of coke – a clutch of bananas The key thing about this exercise is to note that you bought 1 unit of bananas but that came along with 5 individual bananas! Why is that important? Because in balancing chemical equations, some chemicals come by themselves, such as metals while other chemicals are bonded together, such as NaCl Take the formation of Sodium Chloride, imagine yourself in a chemical supermarket: – Grab 2 sodium atoms – Pick up a Chlorine diatomic molecule Let them react, and you will get 2 NaCl! Why does Chlorine atoms bunch up like bananas? The reason is because the elemental state of chlorine is as a diatomic molecule. Whereas the elemental state of Sodium is on its own. The elemental form of something means it is at its’ basic or normal state without combination of other items. Source
Let us examine the elemental form of some elements!
Calcium element has metallic properties. In its elemental state, is in solid state and composed of individual atoms!
Bromine element on its own is in liquid state at room temperature, and it comes in diatomic Br2 molecules (Because a bromine atom needs to form one covalent bond and share a pair of electrons with another bromine atom to attain full electronic outer shell)
And when Calcium reacts with bromine, the product is Calcium Bromide.
And so when it comes to the chemical equation of the reaction, it is written as:
Ca + Br2 -> CaBr2
Ca + 2Br -> CaBr2 which is incorrect because Br in its elemental state is diatomic!
Next on the actual balancing, the rule is to:
Balance the metal,
Balance the partner
With the unbalanced equation below: CaCl2 + Na3PO4 -> Ca3(PO4)2 + NaCl
We usually start from the left-sided metal
Ca —-compare with— Ca3(PO4)2
so add 3 Ca to the left
We got 3CaCl2 + Na3PO4 -> Ca3(PO4)2 + NaCl
Then balance the partner
3CaCl2 means we have 6Cl
So we need to have 6NaCl on the right
We get 3CaCl2 + Na3PO4 -> Ca3(PO4)2 + 6NaCl
Now balance partner of 6NaCl, we got 6Na, so the Na comes from Na3PO4
so we need 2 Na3PO4 to provide that many Na atoms
We get 3CaCl2 + 2Na3PO4 -> Ca3(PO4)2 + 6NaCl
The other type of balancing chemical equations you will see is the organic chemistry type… where hydrocarbons react with oxygen where the trouble is oxygen appears in a number of products.
Last but not least, you need to know about ionic equations!
1) Include state symbols in your workings
2) Remove those that have the same state symbol on both sides
To balance Chemical Equations, this video is fabulous!!!
After watching the video, do try out practice questions from this link which is very cool!