Question

As part of an experiment, a student burns propane (C3H8) to produce carbon dioxide (CO2) and water (H2O). She remembers that she must follow the Law of Conservation of Matter when writing a balance chemical equation. Which of these equations adheres to the Law of Conservation of Matter?

Answer 1

`C_3H_8 + 5O_2\longrightarrow 3CO_2+4H_2O`

Step-by-step explanation:

The chemical equation for this reaction is without balanced is:

`C_3H_8 + O_2\longrightarrow CO_2+H_2O`

We take oxygen in reactants because these reactions are done in air not in vacuum.

Now , according to law of conservation of matter in any closed system the amount of matter remains constant after transition of matter.

So we need to balance each and every elements present in the above equation i.e. O(oxygen), H(hydrogen) and C(carbon).

So we will follow the standard method of balancing the equation.

First we balance carbon both sides. The carbon in right side should be 3 to balanced with carbon in left side.

Therefore,
`C_3H_8 + O_2\longrightarrow 3CO_2+H_2O`

Similarly, we also balance hydrogen .To do so we need 8 hydrogen molecules in right side so we prefix 4 in
`H_2O` molecule since water itself have two hydrogen molecule they multiply to get total of 8 hydogen atom.

`C_3H_8 + O_2\longrightarrow 3CO_2+4H_2O`

So, till now we have balanced carbon and hydron.

Now, their are total 10 oxygen atom in right hand side. 6 form
`3CO_2`

and 4 form
`4H_2O`.

So , we also balance these and multiplying 5 with
`O_2` to get 10 oxygen atoms both sides.

And final balanced equation we get is:

`C_3H_8 + 5O_2\longrightarrow 3CO_2+4H_2O`

Hence , this is the required solution.