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Explanation:
Percentage ethylene by weight = 57%
Percentage propylene by weight = 43%
Suppose in 100 grams of polymer:
Mass of ethylene = 57 g
Mass of propylene = 43 g
Moles of ethylene = 
Moles of propylene = 
1 mole =
molecules/ atoms
Units of ethylene = 
Units of propylene = 
a) Fraction of ethylene units:

b ) Fraction of propylene units:

Answer:
0.8 mol.
Explanation:
- The balanced equation for the reaction between Al and FeO is represented as:
<em>2Al + 3FeO → 3Fe + Al₂O₃,</em>
It is clear that 2 mol of Al react with 3 mol of FeO to produce 3 mol of Fe and 1 mol of Al₂O₃.
<em><u>Using cross multiplication:</u></em>
2 mol of Al needs → 3 mol of FeO, from stichiometry.
??? mol of Al needs → 1.2 mol of FeO.
∴<em> The no. of moles of Al are needed to react completely with 1.2 mol of FeO </em>= (2 mol)(1.2 mol)/(3 mol) = <em>0.8 mol.</em>
If a sample is packed poorly, the sample will not heat evenly and will take longer to melt.