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important : mass - mass calculations past hsc question (1 Viewer)

clicker

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when lead oxide is heated with carbon, metallic lead is formed.

2PbO (s) + C (s) ------> 2Pb (s) + CO2 (g)

if 87.3g of lead oxide were mixeed with 2.62g of charcoal (carbon), what mass of metallic lead would be formed ?
 

miss_b

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m(PbO)=87.3g
M(PbO)=223.19g/mol
n(PbO)= m/M = 0.3911466mol

m(C)=2.62g
M(C)=12g/mol
n(C)= m/M = 0.218333mol

n(PbO) : n(C)
=2:1
So C is in excess

n(PbO):n(Pb)
=2:2

n(Pb)=0.3911466mol
M(Pb)=207.19g/mol
m(Pb)=M*n= 81.0g
 
Last edited:

miss_b

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Sorry, made a mistake...

Corrected it now with working out :)
 

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