Q29P - Chemistry: Molecular Nature Of Matter And Change

Question

The mass percent of sulfur in a sample of coal is a key factor in the environmental impact of the coal because the sulfur combines with oxygen when the coal is burned and the oxide can then be incorporated into acid rain. Which of the following coals would have the smallest environmental impact?

	Mass (g) of Sample	Mass(g) of Sulfur in Sample
Coal A	378	11.3
Coal B	495	19.0
Coal C	675	20.6

Step-by-Step Solution

Answer

In this question, we have to choose a small sulfur %, because the coal containing the lowest sulfur percentage they have the lowest environmental impact.

Hence in the below steps of the calculation, we can conclude that Coal A contains the lowest % of Sulfur, so it has the lowest environmental impact.

The percentage of Coal A calculated is 2.98%.

Step1. Calculation of the lowest sulfur %

In this question, we have to choose a small sulfur %, because the coal containing the lowest sulfur percentage they have the lowest environmental impact.

So to calculate the smallest sulfur percentage we have:

(Lowest S % ) S% $=\frac{\mathrm{m}\left(\mathrm{S}\right)}{\mathrm{m}\left(\mathrm{Sample}\right)} \times 100$

Step2. Calculation of the lowest sulfur % in above 3 cases of coal. And comparing them.

$$\begin{gathered} \mathrm{a}) \%\mathrm{S} =\frac{11.3}{378}\times 100 = 2.98\% \\ \mathrm{b}) \%\mathrm{S}=\frac{19}{495}\times 100 = 3.84\% \\ \mathrm{c}) \%\mathrm{S}=\frac{ 20.6 }{67.5}\times 100 = 30.5\% \end{gathered}$$

Hence in the above calculation, we can conclude that Coal A contains the lowest % of Sulfur, so it has the lowest environmental impact.

And here, the lowest S% calculated is 2.98%.