1848d3885a4a7490e52e259d177d933c513f2dd2
   1# Gases
   2
   3## Comibned gas equation
   4
   5$${P_1 V_1 \over T_1} = {P_2 V_2 \over T_2}$$
   6
   7## Perfect gas equation
   8
   9$$PV=nRT$$
  10
  11where $R =$ universal gas constant $= 8.31 \text{J} \text{K}^{-1} \text{mol}^{-1}$  
  12$P$ is measured in kPa
  13$V$ is measured in L
  14$T$ is measured in K
  15$n$ is no of mol of gas
  16
  17
  18- **Standard temperature and pressure (STP)** - standard temperature is 0 $^\circ$ C or 273 K. Standar dpressure is 100.0 kPa
  19- **Standard laboratory conditions (SLC)** - temperature 25 $^\circ$ C (298K), pressure 100.0 kPa
  20
  21## Molar gas volume
  22
  23> Equal volumes of all gases measured at the same temperature and pressure contain the same number of gas particles
  24
  25$\therefore$ 1 mole of any gas at SLC occupies 24.8L - **molar gas voluem**
  26
  27$$n={V \over V_M}$$
  28
  29where $n$ = number of mol  
  30$V$ = actual volume (in litres)  
  31$V_m$ = molar volume of gas
  32
  33$$\therefore n_{SLC} = {V \over 24.8}$$