Question

A student observes the chemical process described by this equation:

4Al + 3O2 → 2Al2O3

How does the mass of the new substance compare to the total mass of the starting materials?

Answer 1

Both are equal

Step-by-step explanation:

Mass of starting material i.e Aluminium is
`4.480 * 10^(-23)` grams

The weight of oxygen is
`2.65 * 10^(-23)`

There are 4 atoms of aluminium and 3 atoms of oxygen

Thus, the total mass of starting material is

`4 *` mass of one atom of aluminium
`+ 6 *` mass of one atom of oxygen

`4 * 4.480 * 10^(-23) + 6* 2.65 * 10^(-23)`

`35.1 * 10^(-23)` grams

Mass of new substance is also equal to

`4 *` mass of one atom of aluminium
`+ 6 *` mass of one atom of oxygen

`4 * 4.480 * 10^(-23) + 6* 2.65 * 10^(-23)`

`35.1 * 10^(-23)` grams