Q. 8: Calculate the number of Mole and Molecules in the followings:
(a) 0.16 g of CH4 (b) 9 g of Water (H20)
Answers
answers:
no. of moles of CH4 = 0.0099
no. of molecules of CH4 = 6.004 x 10²¹
no. of moles of H2O = 0.5
no. of molecules of H2O = 3.01 x 10²³
solutions:
formulae
no. of moles = given mass/molar mass
no. of molecules = no. of moles x Avagadro's number
a)
data
given mass of CH4 : 0.016g
molar mass = = = = : 16.04
no. of moles = = = : x
no. of moleculs = = : y
solution
no. of moles = given mass/molar mass
x = 0.016/ 16.04
x = 0.0099 moles
no. of moles = 0.0099
no. of molecules = no. of moles x avagadro's number
y = 0.0099 (6.02 x 10²³)
y = 0.06004 x 10²³
y = 6.004 x 10²¹
no. of molecules = 6.004 x 10²¹
b)
data:
given mass of H2O: 9
molar mass = = = = =: 18
no. of moles = = = = =: x
no. of molecules = = : y
solution:
no. of moles = given mass/molar mass
x = 9/18
x = 0.5 moles
no. of moles = 0.5
no. of molecules = no. of moles x avagadro's number
y = 0.5 ( 6.02 x 10²³)
y = 3.01 x 10²³
no. of molecules = 3.01 x 10²³