Pexel
Hello everyone, today I am going to discuss on gas law.
Some scientist observed the movement of gases and came up with the conclusion that gases react to pressure , volume and temperature.
Some of these scientist are ; Boyle, Charles, Dalton and Graham.
Boyle's law
He stated the law that the volume of a given mass of gas is inversely proportional to the pressure, provided that the temperature remains constant.
In this law, we can tell that as the pressure increases , the volume decreases and vice versa.
Mathematically, the law is
P=K÷V making K the subject of the formula we have K =PV Boyle's law.
Where V=volume at pressure P.
K=mathematical constant .
For a given mass of gas , the product of it's pressure is always constant.
For instance, if the pressure increase by five , the volume will decrease by five . Therefore, Boyle's law can be mathematically be represented as
P1V1=P2V2
Where P1 is the pressure at V1 and P2 is the pressure at V2.
Image source pixabay
Let's solve a problem as example.
375cm³of gas has a pressure of 770mmHg. Find it's volume if the pressure is 750mmHg
Solution;
P1V1=P2V2=Boyle's law
P1= 770mmHg
V1=357cm³
P2=750mmHg
V2=?
.•.make V2 subject of formula
V2=P1 V1÷P2
V2=770×375÷750
V2=385cm³
Before I go to Charles' law I would like to show you how to calculate temperature conversion because is needed in calculation of Charles law
The two major scales are kelvin and Celsius.
Kelvin scale has -273°c as it's starting point.
Celsius has 273k as its starting point
Kelvin temperature is absolute or standard temperature.
Temperature conversion calculation
To get kelvin scale the formula is
K=°c +273
To get Celsius the formula is
°c=K-273
Let's solve some problems as example
Convert 148°c to kelvin
Solution
K=°c+273
.•. 148+237
K=421
Convert 125k to celsius
Solution
°c=K-273
.•. °c=125-273
°c=-148
Charles' law;
He stated in his law that the volume of a given mass of gas is directly proportional to the temperature, provided that the pressure remains constant.
In his law, if the volume increases, the temperature increases and vice versa.
Mathematically, Charles' law is
V=KT
K=V÷T
Where V=volume
T=temperature in Kelvin
K=constant
If we divide the varying gas volume by the corresponding temperature,the result would always be constant. Thus, Charles'law can be represented as
V1÷T1=V2÷T2
Where V1 is the volume at T1
V2 is the volume at T2
Let's solve a problem as example
At17°c, a sample of hydrogen gas occupies 124cm³. What will be the volume at 100°c
Solution
V1÷T1=V2÷T2 Charles' law
V1=35cn³
T1=17+273=290k
V2=?
T2=100+273=373
V2=T2V1÷T1
V2=125×373÷290
V2=161cm³
Thanks for stopping by. ❤️❤️❤️