11. One of the reactions that take place inside a blast furnace to produce iron
ID: 831509 • Letter: 1
Question
11. One of the reactions that take place inside a blast furnace to produce iron is the reduction of iron ore by carbon
monoxide. Choose the answer that represents the sum of all the coefficients when this equation is balanced the
smallest whole number coefficients.
Fe2O3 + CO ? CO2 + Fe
a. 5
b. 9
c. 4
d. 7
e. 6
12. Consider the following balance equation.
2H2 + O2 ? 2H2O
Which one of the following statements is false?
a. One molecule of O2 will react with 2 molecules of H2
b. One mole of O2 will react with 2 moles of H2.
c. The complete reaction of 32.0 g of O2 will produce 2 moles of H2O.
d. The complete reaction of 2.0 g of H2 will produce 36.0 g of H2O.
e. The amount of reaction that consumes 32.0 g of O2 produces 36.0 g of H2O.
13. The thermite reaction is performed using 8.6 g Fe2O3 and 1.8 g powdered Al metal. Which reactant is in excess and by how much?
Fe2O3 + 2 Al ?A12O3 + 2Fe
a. Al, 0.3 g
b. Fe2O3, 2.0 g
c. Al, 2.1g
d. Al, l.lg
e. Fe2O3, 3.3 g
14. Calculate the molarity of a solution that contains 70.0 g of H2SO4 in 280. mL of solution.
a. 2.55 M
b. 6.84 M
c. 8.62 M
d. 9.78 M
e. 11.84 M
15. A laboratory stock solution is 1.50 M NaOH. Calculate the volume of this stock solution that would be needed to prepare 300. mL of 0.200 M NaOH.
a. 2.25 mL
b. 10.0 mL
c. 40.0 mL
d. 1.00 mL
e. 0.100 mL
16. Which element and group are not correctly matched?
Element Periodic Group or Classification
a. Sb metalloid
b. Kr noble gas
C. Al alkali metal
d. F halogen
e. Ca alkaline earth metal
17. Which one of the following is a strong acid?
a. HF
b. HNO3
c. CH3COOH
d. H2SO3
e. H2CO3
18. Which one of the following compounds is incorrectly identified as to type of compound?
Substance Type of Compound
a. KOH strong base
b. HC1O4 strong acid
C. HNO2 weak acid
d. NH3 insoluble base
e. H2SO3 weak acid
19. Which one of the following is a weak electrolyte?
a. KBr
b. H2SO4
c. H2CO3
d. NH4ClO
e. Ca(OH)2
Explanation / Answer
11. --> Fe2O3+3CO = 2Fe + 3 CO2
So, Answer is b. 9
12. --> The complete reaction of 2.0 g of H2 will produce 36.0 g of H2O.
The statement (d) is false because 1 mol of H2 have 2 g of H2 in it. If you look at the equation, 2 mol of H2 needs for complete reaction mean H2 need here is 4 g
So, Answer is d.
13. --> Fe2O3 + 2 Al ?A12O3 + 2Fe
Though the right side of the equation is weirded out. The balanced left hand part has 1 mole of Fe2O3 reacting with 2 moles of Al.
The calculations 1.8 grams of Al is 1.8/27 = 0.0666 moles .
8.6 grams of Fe2O3 = 8.6 /159 = 0.0541 moles.
since the molar ratio of reaction is 1:2 you will need only 0.0333 moles of Fe2O3 to react with 0.066 moles of Al so Fe2O3 is in excess by
0.0541-0.0333 = 0.02076 moles of excess Fe2O3
from the above reacxtion 159 grams of Fe2O3 react with 54 grams of Al so 159/54 = x /1.8grams = 5.3 grams of Fe2O3 needed...5.3 grams/159 grams/mole = 0.0333 moles NEEDED given that you have 8.6 grams the amount not needed ..in excess is 8.6 - 5.3 = 3.3 grams 3.3 grams/159grams/mole = 0.0276 moles.
So, Anwser is e. Fe2O3, 3.3 g
14. --> Molarity = moles of solute/L of solution
First, convert grams of H2SO4 into moles by dividing by its molar mass. The molar mass of H2SO4 is 98.0785.
70/98.0785 = 0.7137 moles
Also convert 280 mL into L by dividing by 1000.
280/1000 = .28 L
M = mol/L
M = .7137/.28
M = 2.548
So, Answer is a. 2.55 M
15. --> a. 2.25 mL
16. --> Al and alkali metal, which element and group are not correctly matched.
Answer is C.
17. --> HNO3 , which is a strong acid
Answer is b.
18. --> Answer is d.
19. --> H2CO3 is a weak electrolyte.
So, Answer is C.
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