Answer:
The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.
Explanation:
Pressure in the container is P and volume is V.
Temperature of the helium gas molecules =
Molecules helium gas = x
Moles of helium has = 
PV = nRT (Ideal gas equation)
...[1]
After removal of helium gas only a fourth of the gas molecules remains and pressure in the container and volume should remain same.
Molecules of helium left after removal = 
Moles of helium has left after removal = 
...[2]




The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.
Answer:
D
Explanation:
D. V1P1 / T1=V2P2 / T2 is correct
Answer:
3Ba(OH)2 + 2H3PO4 —> Ba3(PO4)2 + 6H2O
Explanation:
Ba(OH)2 + H3PO4 —> Ba3(PO4)2 + H2O
There are 3 atoms of Ba on the right side and 1atom on the left side. It can be balance by putting 3 in front of Ba(OH)2 as shown below:
3Ba(OH)2 + H3PO4 —> Ba3(PO4)2 + H2O
There are 2 atoms of P on the right side and 1atom on the left. It can be balance by putting 2 in front of H3PO4 as shown below:
3Ba(OH)2 + 2H3PO4 —> Ba3(PO4)2 + H2O
Now, there are a total of 12 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 6 in front of H2O as shown below:
3Ba(OH)2 + 2H3PO4 —> Ba3(PO4)2 + 6H2O
Now the equation is balanced as the numbers of the atoms of the different elements present on both sides are equal
Answer:
Energy is released as heat during the reaction.