Question 1 of 12 4.0/ 4.0 Points
How many moles of bromine gas are in 37.7 grams?
A. 0.472
B. 3.01 × 103
C. 0.236
D. 79.9
E. none of the above
Answer Key: C
Question 2 of 12 4.0/ 4.0 Points
What is the mass of 3.09 × 1024 atoms of sulfur in grams?
A. 9.91 × 1025
B. 165
C. 0.160
D. 9.64 × 1022
E. none of the above
Answer Key: B
Question 3 of 12 4.0/ 4.0 Points
A redox reaction has occurred ________.
A. when one substance transfers protons to another
B. when one substance forms a solid
C. when an alkali metal reacts with an alkaline earth metal
D. when a substance reacts with elemental oxygen
E. when all of the above occur
Answer Key: D
Question 4 of 12 4.0/ 4.0 Points
In writing the chemical equation for a precipitation reaction, what abbreviation of the physical state must appear with one of the products?
A. (g)
B. (l)
C. (w)
D. (s)
E. none of the above
Answer Key: D
Question 5 of 12 0.0/ 4.0 Points
What is the complete ionic equation for the reaction of hydrochloric acid with potassium hydroxide?
A. H+ + Cl- + K+ + OH- ? H2O + K+ + Cl-
B. H+ + Cl- + K+ + OH- ? 2H+ + O2- + K+ + Cl-
C. 2H+ +2Cl- + K2+ + 2OH- ? H2O + K2+ +2 Cl-
D. H+ + OH- ? H2O
E. none of the above
Answer Key: A
Question 6 of 12 4.0/ 4.0 Points
Before a chemical equation can be written, one must know
A. the molar mass of all the compounds.
B. the number of moles of all reactants and products.
C. the atomic mass of all the elements involved.
D. the symbols and formulas of all reactants and products.
E. none of the above.
Answer Key: D
Question 7 of 12 0.0/ 4.0 Points
Iron metal reacts with oxygen to produce iron(III) oxide. If you have 12.0 moles of iron for complete reaction, you need
A. 4.5 moles of O2 and produce 3.0 moles of Fe2O3.
B. 12.0 moles of O2 and produce 24.0 moles of Fe2O3.
C. 9.0 moles of O2 and produce 3.0 moles of Fe2O3.
D. 9.0 moles of O2 and produce 6.0 moles of Fe2O3.
E. none of the above
Answer Key: D
Question 8 of 12 0.0/ 4.0 Points
How many moles of chlorine gas are needed to make 0.6 moles of sodium chloride? Given the reaction: 2Na + Cl2 ? 2NaCl
A. 0.3
B. 1.2
C. 3.6
D. 0.6
E. not enough information
Answer Key: A
Question 9 of 12 0.0/ 4.0 Points
Suppose two chemical reactions are linked together in a way that the O2 produced in the first reaction goes on to react completely with Mg to form MgO in the second reaction. Reaction one: 2 KClO3 ? 3 O2 + 2 KCl Reaction two: 2 Mg + O2 ? 2 MgO If you start with 4 moles of KClO3, how many moles of MgO could eventually form?
A. 4 moles
B. 12 moles
C. 6 moles
D. 2 moles
E. none of the above
Answer Key: B
Question 10 of 12 4.0/ 4.0 Points
If the theoretical yield of a reaction is 42.0 grams of product and the percent yield is 75%. How many grams were actually produced?
A. 32
B. 5400
C. 56
D. 1.8
E. none of the above
Answer Key: A
Question 11 of 12 0.0/ 5.0 Points
Sodium peroxide (Na2O2) reacts with water to form sodium hydroxide and oxygen gas. Write a balanced equation for the reaction and determine how much oxygen in grams is formed by the complete reaction of 35.23 g Na2O2.
Na2O + H2O ====> 2 NaOH
Comment: Na2O2 + 2 H2O
4 NaOH + 3 O2
Question 12 of 12 0.0/ 5.0 Points
A 7.96 gram sample of silver reacts with oxygen to form 8.55 gram of the metal oxide. What is the formula of the oxide?
NgO2
Comment: Ag2O
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