A container holds a sample of hydrogen gas at 300 K. The temperature decreased to 100 K and the pressure remained constant, and the volume changed to 1.0 L. What was the original volume?

Answer : The original volume of gas was, 3.0 L

Explanation :

Charles' Law : It is defined as the volume is directly proportional to the temperature of the gas at constant pressure and number of moles.

or,

where,

are the initial volume and temperature of the gas.

are the final volume and temperature of the gas.

We are given:

Now put all the given values in above equation, we get:

Thus, the original volume of gas was, 3.0 L

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.