Answer:
Explanation:
1) Given data:
Number of moles of lead = 4.3×10⁻³ mol
Mass of lead = ?
Solution:
Mass = number of moles × molar mass
Molar mass of lead = 207.2 g/mol
Mass = 4.3×10⁻³ mol × 207.2 g/mol
Mass = 890.96 g
2) Given data:
Number of atoms of antimony = 3.8×10²² atoms
Mass of antimony = ?
Solution:
1 mole contain 6.022 ×10²³ atoms
3.8×10²² atoms × 1 mol / 6.022 ×10²³ atoms
0.63×10⁻¹ mol
0.063 mol
Mass = number of moles × molar mass
Molar mass of lead = 121.76 g/mol
Mass = 0.063 mol × 121.76 g/mol
Mass = 7.67 g
3) Given data:
Mass of tungsten = 15.5 Kg (15.5 kg × 1000 g/ 1kg = 15500 g)
Number of atoms = ?
Solution:
Number of moles of tungsten:
Number of moles = mass/molar mass
Number of moles = 15500 g / 183.84 g/mol
Number of moles = 84.3 mol
1 mole contain 6.022 ×10²³ atoms
84.3 mol × 6.022 ×10²³ atoms / 1mol
507.65 ×10²³ atoms
