How many atoms of hydrogen are in 2.50g of water

1.67 ×10²³ atoms of hydrogen present in 2.5 g of water.

Explanation:

Given data:

Mass of  water = 2.5 g

Number of hydrogen atoms= ?

Solution:

First of all we will calculate the molar mass of water.

Molar mass of H₂O = 16 +1 ×2 = 18 g/mol

The number of atoms will be determine through the Avogadro number.

The number 6.022×10²³ is called Avogadro number and it is the number of atoms or molecules in one gram of atoms of an element or one gram molecules of a compound.

First of all we will calculate the number of moles of water in 2.5 g.

Number of moles = mass /molar mass

Number of moles = 2.5 g / 18 g/mol

Number of moles = 0.139 mol

The number of molecules of water in 10 g.

0.139 × 6.022×10²³ = 0.837 ×10²³molecules

one water molecule contain two hydrogen atoms. For 0.837×10²³ molecules,

0.837×10²³× 2 = 1.67 ×10²³ atoms

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml