Chem Test Unit 4

B. C3H6O

A sample of a compound known to consist of only carbon, hydrogen, and oxygen is found to have a total mass of 29.05g. If the mass of carbon is 18.02g, and the mass of hydrogen is 3.03 g, what is the empirical formula of the compound?

B. The temperature of the reaction mixture increases

A student had two dilute, colorless solutions, HCL (aq) and NaOH (aq), which were at the same temperature. The student combined the solutions, and the reaction represented above occurred. Which of the following results would be evidence that a chemical reaction took place?

D. FeS (s) is the limiting reactant and 0.5 mol of O2 (g) remains unreacted

Due to the presence of FeS(s) as an impurity, the combustion of some types of coal results in the formation of SO2, as represented by the equation above. Which of the following statements is correct when 2.0 mol of FeS(s) reacts with 4.0 mol of O2 (g)?

D. It is a redox reaction, because Cu(s) is oxidized and the nitrogen atom in NO3^-(aq) is reduced

Each student in a class placed a 2.00 gram sample of a mixture of Cu and Al in a beaker and placed the beaker in a fume hood. The students slowly poured 15.0 mL of 15.8 M HNO3(aq) into their beakers. The reaction between the copper in the mixture and the HNO3(aq) is represented by the equation above. The students observed that a brown gas was released from the beakers and that the solutions turned blue, indicating the formation of Cu^2+(aq). The solutions were then diluted with distilled water to known volumes. Which of the following is true about the reaction?

D. H2O (l) and Cl- (aq)

For the dissolution of HCl in water represented above, which of the following pairs includes the Brosted-Lowry bases (meaning the base and the conjugate base)?

A. 0.20 g of H2

If 0.40 mol of H2 and 0.15 mol of O2 were to react as completely as possible to produce H2O, what mass of reactant would remain?

A. NH3 is a strong conjugate base

In the reaction above, NH4+(aq) acts as a weak acid. Which of the following must be true?

A. CrO4^2-

In which of the following compounds is the oxidation number of chromium the greatest?

B. Fe2(CO3)3

Slats containing haldide ions are soluble for those containing silver, lead, and mercury. Salts containing carbonate anions are insoluble excepts for those containing alkali metals or ammonium. If solutions of iron (III) nitrate and sodium carbonate are mixed, what would be the formula of the precipitate?

B. Oxidation Half Reaction: Cu --> Cu^+2 + 2e- Reduction Half Reaction: Ag+ + e- --> Ag

The reaction between solid copper and aqueous silver nitrate produces solid silver and a blue solution, as represented by the balanced equation shown above. Based on the balanced equation, which of the following identifies the oxidation and reduction half reaction?

A. Equation A (2Mg + O2 --> 2MgO)

Use the four equations below for the following two questions. Choose the equation that represents an oxidation reaction that is also a synthesis reaction:

B. Equation B (Pb^+2 + CrO4^-2 --> PbCrO4)

Use the four equations for the following two questions. Choose the equation that represents a precipitation reaction:

D. 64 grams

What mass of oxygen is in 148 grams of calcium hydroxide (Ca(OH)2)?

D. 4

When the equation above is balanced and all coefficients are reduced to lowest whole-number terms, what is the coefficient for H3PO4?

D. Cu2O

Which of the following compounds contains an element in a +1 oxidation state, before you balance according to subscripts?

B. The acid is HNO2, and the conjugate base is NO2^- (aq)

Which of the following correctly identifies a Bronsted-Lowry conjugate acid-base pair in a solution prepared by mixing together HNO2 (aq) and NH3 (aq)?

D. 2Ag+(aq) + Ni(s) --> 2Ag(s) + Ni2+(aq)

Which of the following is the balanced net ionic equation for an oxidation-reduction reaction between Ag+(aq) and Ni(s) based on the half reactions represented above?

B. NH3

Which of the following is the conjugate acid of NH2^-?

D. Equation D

Which of the following is the net ionic equation for the reaction between aqueous sodium fluoride and hydrochloric acid?

C. NO3^-(aq) --> NO(g)

Which of the following represents a process in which a species is reduced?