Apiston-cylinder device contains 257 grams of r134a at 60 kpa and -20°c. the r134a is heated until its temperature reaches 100°c. determine the total change of volume.

Answer : The total change of volume is, 41.883 liters.

Explanation :

R134a is a 1,1,1,2-tetrafluoroethane. It is a hydro-fluorocarbon and haloalkane gaseous refrigerant.

First we have to calculate the volume at .

Using ideal gas equation:

where,

n = number of moles

w = mass of R134a = 257 g

P = pressure of the gas = 60 Kpa

T = temperature of the gas =

M = molar mass of R134a  = 102.03 g/mole

R = gas constant = 8.314 Kpa.L/mole.K

V = initial volume of gas

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

Now we have to calculate the volume at by using Charles's law.

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

or,

where,

= initial volume of gas = 88.305 L

= final volume of gas = ?

= initial temperature of gas = 253 K

= final temperature of gas =

Now put all the given values in the above formula, we get the final volume of the gas.

Now we have to calculate the total change of volume.

Therefore, the total change of volume is, 41.883 liters.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2