Answer:
Explanation:
Given data:
Number of molecules of H₂O = 3.01 × 10²³
Mass of H₂O = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
1 mole = 6.022 × 10²³ molecules
3.01 × 10²³ molecules × 1 mol / 6.022 × 10²³ molecules
0.5 moles of water
Mass of water:
Mass = number of moles × molar mass
Mass = 0.5 mol × 18 g/mol
Mass = 9 g
2)
Number of formula units of CaBr₂ = 8.32 × 10²⁰
Mass of CaBr₂ = ?
Solution:
8.32 × 10²⁰ formula units × 1 mol / 6.022 × 10²³ formula units
1.4×10⁻³ moles of CaBr₂
Mass of CaBr₂:
Mass = number of moles × molar mass
Mass = 1.4×10⁻³ mol × 199.89 g/mol
Mass = 279.85×10⁻³ g
3)
Number of molecules of XeF₆ = 1.93 × 10²⁶
Mass of XeF₆ = ?
Solution:
1.93 × 10²⁶ molecules × 1 mol / 6.022 × 10²³ molecules
0.32 × 10³ mol
Mass of XeF₆:
Mass = number of moles × molar mass
Mass = 0.32 × 10³ mol × 245.28 g/mol
Mass = 78.5 × 10³ g
