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Given the balanced equation below, calculate the moles of aluminum that are needed to react completely with 17.5 moles of FeO? You must show all of your work.

2Al + 3FeO à 3Fe +Al2O3

Sodium and water react according to the following equation. If 51.5g of sodium are added to excess water, how many liters of hydrogen gas are formed at STP? Show all work for credit.

2Na + 2H2O à 2NaOH + H2

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kenmyna

   Question 1

 The moles  off Al that are needed to react  completely  with   17.5  moles  of FeO  is 11.67  moles

 calculation

2Al + 3 FeO→ 3 Fe + Al₂O₃

From equation above Al: FeO  is 2:3

therefore the  moles of Al  = 17.5 moles x 2 /3 = 11.67  moles


Question 2

The number of liters  of hydrogen gas that are formed at STP  25.088 L

calculation

2Na + 2H₂O  →  NaOH +H₂

Step 1 : calculate the moles of Na

moles = mass÷ molar mass

from  the periodic table the  molar  mass of Na = 23 g/mol

moles= 51.5 g÷ 23 g/mol =2.24 moles

Step 2: use the mole ratio to determine the moles of H₂

Na:H₂  is 2:1 therefore the moles of H₂ = 2.24 moles x 1/2 =1.12 moles


Step 3: calculate the number of liters of H₂ at STP

that  is at STP   1 mole of a gas = 22.4 L

                           1.12  moles = ? L

by cross multiplication

=( 1.12 moles x 22.4 L) / 1 mole = 25.088 L