Chemistry help can you answer

Question

i need help can you show me how and the answera sample of B2H6 gas in a 35-mL container is at a pressure of 450mm Hg and a tempature of 625 C if the gas is allowed to cool at a constant volume untill the pressure is 375 mm Hg what is the new tempature in C ?

Answer 1

according to one of the gas laws, the temperature of a substance is directly proportional to its pressure, so:

P1/T1=P2/T2 with the pressure being in torrs (or mm Hg), and the temperature being in Kelvin

Kelvin is just C+273, so 898K to start with.

450/898=375/x

450x=336750

x=748 1/3K

then convert back to celcius 748 1/3-273

475 1/3

Answer 2

PV = nRT

So, as long as the number of moles does not change (no chemical reaction)

P1V1/T1 = nR = P2V2/T2

In this example, V1 = V2, so it's even easier;

P1/T1 = P2/T2

You know all the other numbers, so just solve for T2.  Remember that T must be in K.

Answer 3

Use the formula PV = nRT

If no reaction is occuring then complete these steps.

P = Pressure V = Volume T = Temperature

Like the other guys said: P1V1/T1 = nR = P2V2/T2

The volume remains constant so V1 = V2

So now your formula looks like this : P1/T1 = P2/T2

Convert Celcius to Kelvin

(450mm Hg)/898K = (375mm Hg)/X

X = T2 = New temperature

Now it's just like basic algebra:

X= (375)(898) / (450)

X = 748.3 K

now convert to celcius

X = 475.3 degrees C