Answer:
0.302 moles
Explanation:
Data given
Mass of Pb(NO₃)₂ = 100 g
Moles of Pb(NO₃)₂ = ?
Solution:
To find mole we have to know about molar mass of Pb(NO₃)₂
So,
Molar mass of Pb(NO₃)₂ = 207 + 2[14 + 3(16)]
= 207 + 2[14 + 48]
= 207 + 124
Molar mass of Pb(NO₃)₂ = 331 g/mol
Formula used :
no. of moles = mass in grams / molar mass
Put values in above formula
no. of moles = 100 g / 331 g/mol
no. of moles = 0.302 moles
no. of moles of Pb(NO₃)₂ = 0.302 moles
Answer:
2.19 x 10^-12.
Explanation:-
The relation between Ka and Kb for an acid and it's conjugate base is
Ka x Kb = Kw where Kw = ionic product of water.
So Kb = 10^-14 / (4.57 x 10 ^ -3)
= 2.19 x 10^-12
2.91 mol Al * ( 26.982 g Al / 1 mol Al) = 78.518 grams