1# Gases 2 3## Perfect gas equation 4 5$$PV=nRT$$ 6 7where $R =$ universal gas constant $= 8.31\text{J} \text{K}^{-1} \text{mol}^{-1}$ 8$P$ is measured in kPa 9$V$ is measured in L 10$T$ is measured in K 11$n$ is no of mol of gas 12 13 14- **Standard temperature and pressure (STP)** - standard temperature is 0 $^\circ$ C or 273 K. Standar dpressure is 100.0 kPa 15- **Standard laboratory conditions (SLC)** - temperature 25 $^\circ$ C (298K), pressure 100.0 kPa 16 17## Molar gas volume 18 19> Equal volumes of all gases measured at the same temperature and pressure contain the same number of gas particles 20 21$\therefore$ 1 mole of any gas at SLC occupies 24.8L - **molar gas voluem** 22 23$$n={V \over V_M}$$ 24 25where $n$ = number of mol 26$V$ = actual volume (in litres) 27$V_m$ = molar volume of gas 28 29$$\therefore n_{SLC} = {V \over 24.8}$$