A vertical hydroponic greenhouse contains dry air at a temperature of 12.0 ∘C12.0\ ^\circ\text{C}12.0 ∘C and a pressure of 107 kPa107\text{ kPa}107 kPa.
Show that the amount of air in each cubic metre is about 45 mol45\text{ mol}45 mol.
The density of the dry air is 1.25 kg m−31.25\text{ kg m}^{-3}1.25 kg m−3. Calculate crmsc_{\text{rms}}crms for the air molecules. Give your answer to an appropriate number of significant figures.
Calculate, in K\text{K}K, the change of temperature that will triple crmsc_{\text{rms}}crms for the air molecules.
The greenhouse contains moist air at a temperature of 12 ∘C12\ ^\circ\text{C}12 ∘C. An atmospheric condenser unit cools and then condenses water vapour from the moist air. The final temperature of the liquid water that collects in the condenser unit is 5 ∘C5\ ^\circ\text{C}5 ∘C. Drier air leaves the condenser at a temperature of 12 ∘C12\ ^\circ\text{C}12 ∘C.
Table 1 compares the air flowing into and out from the condenser unit:
| mass of watermass of air\frac{\text{mass of water}}{\text{mass of air}}mass of airmass of water | |
|---|---|
| moist air flowing in | 0.00680.00680.0068 |
| drier air flowing out | 0.00380.00380.0038 |
In one hour, a volume of 1500 m31500\text{ m}^31500 m3 of air flows through the condenser unit. Assume that the density of the air remains constant at 1.25 kg m−31.25\text{ kg m}^{-3}1.25 kg m−3.
Determine how much heat energy is removed in one hour from the water vapour by the condenser unit.
