Chemistry important laws:
GAY LUSSAC'S LAW OF COMBINING VOLUME:
"THE GASES REACT IN SIMPLE WHOLE NUMBER RATIOS TO PRODUCE PRODUCTS"
Boyle's law:
"THE PRESSURE OF A FIXED AMOUNT OF A GAS VARIES INVERSLY WITH IT'S VOLUME,THE TEMPERATURE IS MAINTAINED CONSTANT"
Charle's law:
"AT CONSTANT PRESSURE,THE VOLUME OF A GIVEN MASS OF A GAS VARIES LINEARLY WITH THE ABSOLUTE TEMPERATURE OF THE GAS"
Avagadro's law: 
"IT STATES THAT EQUAL VOLUMES OF ALL GASES AT THE SAME SAME TEMPERATURE AND PRESSURE MUST CONTAIN  EQUAL NUMBER OF MOLECULES"
Dalton's law of partial pressure: 
"THE TOTAL PRESSURE EXERTED BY A GASEOUS MIXTURE IS EQUAL TO THE SUM OF PARTIAL PRESSURES OF EACH GAS PRESENT IN THE MIXTURE"
Grahm's law of diffusion and effusion:
"RATE OF DIFFUSION AND EFFUSION OF A GAS IS INVERSLY PROPORTIONAL  TO THE SQUARE ROOT OF ITS DENSITY"
Hess's law:
"T STATES THAT THE ENTHALPY CHANGE IN A CHEMICAL REACTION IS SAME WEATHER THE REACTION TAKES PLACE IN A SINGLE STEP OR IN SEVERAL STEPS"