Question

Q 1

Calculate the number of calcium ions in 5.6 gram of calcium oxide

Q2 calculate the mass of 12.0 x 10 ¹⁴atoms of hydrogen

Answer 1

Number of moles of CaO = 5.6g CaO/56.08g per mol = 0.099 mol = 0.1 mol


In 1 mol CaO there are 6.022x1023atoms of Ca ion. So, in 0.1 mol there will be
= 0.1 x 6.022x1023atoms



Q2.

6.022×10^23 is 1g

12 × 10^14 is X

therefore X = (12×10^14)/(6×10^23)

X= 2 × 10^-9 g