Question

2AL `(s)` + 6HCL`3(aq)` `rarr` 2AlCl`3(aq)` + 3H`2(g)` 0.040 mol piece of aluminium reacted completely in 20s. the rate of formation of hydrogen gas is?

2AL `(s)` + 6HCL`3(aq)` `rarr` 2AlCl`3(aq)` + 3H`2(g)`

Answer 1

`0.003 "mol/s"`

Explanation:

From the equation, we can see that the ratio of number of moles:

Al : HCl : AlCl3 : H2 (Assuming that HCl3 was a typo)

is equal to:

2 : 6 : 2 : 3 (As the numbers in front of each substances show)

Therefore, if 0.040 mol of aluminium reacted completely, than `0.040 \times 3/2 = 0.060 "mol"` of hydrogen was formed.

Thus, `0.060 \divide 20 = 0.003 "mol/s"`

Hope that makes sense!