If the volume of a confined gas is doubled while the temperature remain constant, what change (if any) would be observed in the pressure

The gas will obey Boyles Law:

P1 V1 = P2 V2      where P1 and V1 are the original pressure and volume and P2 and V2 are the new  values.

If V2 = 2V1  (given) then:

P1 V1 = P2 *2 V1

P2 = P1 V1 / 2V1

P2 = P1 / 2

In other words the pressure is halved. (answer).

- lead + phosphoric acid = hydrogen + lead(ii) phosphate

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.