Question

1. charcoal is burnt at 3.0g per second for 3 hours. calculate (i) volume of carbon(iv) oxide released into the atmosphere at s.t.p (ii) number of moles of oxygen consumed at s.t.p c = 12.0, molar volume at s.t.p = 22.4dm³ 2. state the source of each of the ff. atmospheric air pollutants (i) so₂ (ii) ch₄ (iii) co (ii) what is the effect of each pollutant in above on the environment?

Explanation:

Step1: Calculate the mass of charcoal burned

First, convert 3 hours to seconds. 1 hour = 3600 s, so 3 hours = 3×3600 = 10800 s. The mass of charcoal burned per second is 3.0 g. So the total mass of charcoal burned, $m = 3.0\ g/s×10800\ s=32400\ g$.

Step2: Determine the number of moles of charcoal

The molar - mass of carbon (charcoal is mainly carbon) is $M = 12.0\ g/mol$. The number of moles of carbon, $n_{C}=\frac{m}{M}=\frac{32400\ g}{12.0\ g/mol}=2700\ mol$.

Step3: Write the combustion reaction of carbon

The combustion reaction of carbon is $C + O_{2}
ightarrow CO_{2}$. From the reaction, 1 mole of carbon produces 1 mole of $CO_{2}$ and consumes 1 mole of $O_{2}$.

Step4: Calculate the volume of $CO_{2}$ at STP

At STP, the molar volume is $V_{m}=22.4\ dm^{3}/mol$. The number of moles of $CO_{2}$ produced is equal to the number of moles of carbon burned, $n_{CO_{2}} = 2700\ mol$. The volume of $CO_{2}$, $V_{CO_{2}}=n_{CO_{2}}\times V_{m}=2700\ mol\times22.4\ dm^{3}/mol = 60480\ dm^{3}$.

Step5: Calculate the number of moles of $O_{2}$ consumed at STP

The number of moles of $O_{2}$ consumed is equal to the number of moles of carbon burned, $n_{O_{2}}=2700\ mol$.

Step6: Answer for sources of pollutants

(i) $SO_{2}$: Sources include burning of fossil fuels (coal and oil) that contain sulfur - containing compounds.
(ii) $CH_{4}$: Sources include natural gas leaks, livestock (enteric fermentation in cows), and rice paddies.
(iii) $CO$: Sources include incomplete combustion of carbon - containing fuels, such as in vehicle exhausts.

Step7: Answer for effects of pollutants

(i) $SO_{2}$: It can cause acid rain which damages buildings, forests, and aquatic ecosystems. It also irritates the respiratory system of humans and animals.
(ii) $CH_{4}$: It is a potent greenhouse gas, contributing to global warming and climate change.
(iii) $CO$: It is a toxic gas. It binds to hemoglobin in the blood more strongly than oxygen, reducing the oxygen - carrying capacity of the blood, which can lead to asphyxiation and health problems.

Answer:

(i) Volume of $CO_{2}$ at STP: $60480\ dm^{3}$
(ii) Number of moles of $O_{2}$ consumed at STP: $2700\ mol$
(2) (i) Source of $SO_{2}$: Burning of fossil fuels with sulfur - containing compounds.
(ii) Source of $CH_{4}$: Natural gas leaks, livestock, rice paddies.
(iii) Source of $CO$: Incomplete combustion of carbon - containing fuels.
(3) (i) Effect of $SO_{2}$: Causes acid rain, damages buildings/forests/aquatic ecosystems, irritates respiratory system.
(ii) Effect of $CH_{4}$: Potent greenhouse gas, contributes to global warming.
(iii) Effect of $CO$: Toxic, reduces oxygen - carrying capacity of blood.