Aballoon contains 0.218mol of gas and has volume of 4.8 l. if an additional 0.075 mil of gas is added to the ballon, what is the final volume and how many molecules of gas are in the cylinder?

1. 6.45 L

2. 1.76 x 10²³ molecules

Explanation:

1. Avagadros law states that volume of gas at constant temperature and pressure is directly proportional to the amount / number of moles of that gas

we can use the following equation

v1/n1 = v2/n2

where v1 is volume and n1 is number of moles at first instance

and v2 is volume and n2 is number of moles at second instance

at the first instance - n1 = 0.218 mol

second instance - n2  = 0.218 mol + 0.075 mol  = 0.293 mol

substituting the values

4.8 L / 0.218 mol = v2 / 0.293 mol

v2 = 6.45 L

new volume is 6.45 L

2. 1 mol of any substance is made of 6.022 x 10²³ units. These units could be atoms making up elements or molecules making up a compound.

therefore if 1 mol consists of 6.022 x 10²³  molecules

then 0.293 mol consists of - 6.022 x 10²³ molecules/mol x 0.293 mol = 1.76 x 10²³ molecules

therefore there are 1.76 x 10²³ molecules now in the cylinder

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.