Question

Balancing chemical equations examples questions and answers

Answer 1

1.Write down your given equation.

For this example, you will use:
C3H8 + O2 --> H2O + CO2

2. Write down the number of atoms per each element.

For example, you have 3 oxygen atoms on the right side, but that total results from addition.
Left side: 3 carbon (C3), 8 hydrogen (H8) and 2 oxygen (O2).
Right side: 1 carbon (C), 2 hydrogen (H2) and 3 oxygen (O + O2).

3.Save hydrogen and oxygen for last, as they are often on both sides.

4. Start with single elements

5. Use a coefficient to balance the single carbon atom.
C3H8 + O2 --> H2O + 3CO2

6. Balance the hydrogen atoms next.
C3H8 + O2 --> 4H2O + 3CO2

7. Balance the oxygen atoms.
C3H8 + 5O2 --> 4H2O + 3CO2

Answer 2

Answer:

first of all let me tell you why it's necessary to balance any equation?

balancing chemical equations means that number of atoms of elements should remain same before and after reaction. we know about law of conservation of mass. mass can neither be created nor destroyed. so it's necessary to balance the chemical equations.

now, let's consider two equations.

in first equation, we can clearly see that the number of atoms of elements in both after and before reaction is same. hence it's a balanced equation.

in second equation,

there are 2 atoms in H and Cl before reaction but only one atom in H and Cl after reaction.

so what we can do is, write 2 before HCL. (means coefficient of HCL)

and hence, we get 2 H and 2 Cl.

now it's balanced.

in this way, you can try balancing others. don't over think. first write any number and see..

one more thing, you can only change coefficient of the elements. don't change the number of elements like

because if u change it, then the whole substance will change.

and also no. of atoms of any element = it's coefficient × it's number

for example 2HCl_2,

H = 2

Cl = 2 × 2 = 4

for a easy method, first you can write like this.

LHS :-

Ba = 1

Cl = 2

h = 2

So = 4

RHS :-

Ba = 1

Cl = 1

h = 1

So = 4

it'll help you to compare easily.

later you'll get used to it and then you don't have write like this for comparing.