Chemistry Exam 2

D. -100kJ

A chemical reaction is carried out in a manner such that 150kJ of heat is produced and 50kJ of work is done on the system. ΔE for the process is A. 200kJ B. -200kJ C. 100kJ D. -100kJ

C. 0.80atm

A gas mixture have a total pressure of 2.0atm contains 2.0mol He and 3.0mol Ne. What is the partial pressure of He in this mixture? A. 0.67atm B. 1.0atm C. 0.80atm D. 1.3atm

B. 1.5M

A reagent bottle is labeled ".50M aluminum nitrate." The nitrate concentration in this reagent is A. 2.0M B. 1.5M C. 1.0M D. 0.50M

B. 965mmHg

An open ended mercury manometer is used to measure the gas pressure in a glass bulb as shown below (the difference in height is 225mm, the tube on the gas side is farther down (by 225mm) than the side open to the atmosphere). If atmospheric pressure is known to be 740mmHg, the pressure in the bulb should be reported as A. 225mmHg B. 965mmHg C. 515mmHg D. 985mmHg

C root-mean-square velocity

Consider two gases, A and B, having different molar masses. The gases are maintained at the same temperature and pressure. Which of the following properties would not be the same for the two gases? A. molar volume B. average kinetic energy C. root-mean-square velocity D. all would be the same

a) no reaction b) Pb(NO₃)₂(aq) + 2NH₄Cl(aq) → PbCl₂(s) + 2NH₄NO₃(aq)

Consider what happens when aqueous solutions of the indicated compounds are combined. If a precipitate forms write a balanced molecular equation (with phase labels) for the reaction. If no precipitate forms state that no reaction occurs. a) iron (II) sulfate and potassium bromide b) lead (II) nitrate and ammonium chloride

C. 5.75kJ

How much heat must be supplied to raise the temperature of 275g of ice (specific heat capacity=2.09J/g°C) from -25°C to -15°C? A. 14.4kJ B.8.62kJ C. 5.75kJ D. 1.32kJ

0.225g

Maleic acid (116.1g/mol) is a crystalline solid and a diprotic acid. An impure sample is titrated with 0.122M potassium hydroxide and the equivalence point is observed upon addition of 31.7mL of the base. The impure sample contains how many grams of maleic acid?

2.3L

Pyrite, FeS₂, reacts with oxygen to produce iron (III) oxide and sulfur dioxide according to the equation: 4FeS₂(s) + 11O₂(g) → 2Fe₂O₃(s) + 8SO₂(g) What volume of SO₂ at 30.0°C and 720mmHg could be produced from 4.0g O₂ and an excess of FeS₂?

B. high temperature and low pressure

Real gases behave most like an ideal gas under what conditions? A. high temperature and high pressure B. high temperature and low pressure C. low temperature and high pressure D. low temperature and low pressure

D. real gas molecules are weakly attracted to each other

Real gases do not exactly obey the ideal gas law. One reason is that A. real gas molecules have zero volume B. real gas molecules have nonzero masses C. real gas molecules do not collide with each other D. real gas molecules are weakly attracted to each other

C. acid-base neutralization

The equation below represents a chemical reaction belonging to which classification? H₂C₂O₄(aq) + 2NaOH(aq) → Na₂C₂O₄(aq) + 2H₂O(l) A. combustion B. oxidation-reduction C. acid-base neutralization D. precipitation

C. requires that the energy of the universe must remain constant

The first law of thermodynamics A. requires that energy of the system must decrease B. requires that the energy of the system must remain constant C. requires that the energy of the universe must remain constant D. prohibits the conversion of heat to work

C. electron transfer

The fundamental event in all oxidation-reduction reactions is A. water transfer B. H atom transfer C. electron transfer D. proton transfer

C. 4.0atm

The volume of a fixed amount of gas held at constant temperature is decreased from 8.0L to 4.0L. If the pressure before compression was 2.0atm, what is the pressure after compression? A. 1.0atm B. 2.0atm C. 4.0atm D. 8.0atm

B. +7

What is the oxidation number of chlorine in ClO₄⁻? A. +8 B. +7 C. +2 D. -1

D. 5.7L

What volume is occupied by 16mol of helium gas at pressure 75atm and a temperature of 55°C? A. 0.17L B. 0.96L C. 1.0L D. 5.7L

NH₄⁺ + OH⁻

When ammonia, NH₃, is dissolved in water the resulting solution is weakly electrically conductive. What ions are responsible for the conductivity?

D. BaSO₄

When aqueous solutions of Ba(NO₃)₂, NH₄Cl, and CuSO₄ are mixed a single precipitate forms. What is the empirical formula of the precipitate? A. CuCl₂ B. Ba(SO₄)₂ C. CuCl D. BaSO₄

C. In³⁺ and Br⁻ ions

When solid InBr₃, dissolves in water what species are actually present? A. In⁺ and Br⁻ ions B. In³⁺ and Br³⁻ ions C. In³⁺ and Br³⁻ ions D. InBr₃ molecules

A. Cl₂

Which of the following is not an electrolyte? A. Cl₂ B. H₂SO₄ C. CaCl₂ D. NH₄Cl

D. H₃O⁺

Which of the formulas provides the best (but probably not perfect) description of the nature of a proton in water? A. H₂O⁺ B. H⁺ C. OH⁺ D. H₃O⁺

B. Fe²⁺

Which species is oxidized in the reaction below? 2Fe²⁺(aq) + Ce⁴⁺(aq) → 2Fe³⁺(aq) + Ce²⁺(aq) A. Ce⁴⁺ B. Fe²⁺ C. Fe³⁺ D. Ce²⁺

A. Co³⁺

Which species is the oxidizing agent in the reaction below? 5Co³⁺(aq) + Mn²⁺(aq) + 4H₂O(l) → MnO₄⁻(aq) + 5Co²⁺(aq) + 8H⁺(aq) A. Co³⁺ B. Mn²⁺ C. MnO₄⁻ D. Co²⁺

a)2H⁺(aq) + 2NO₃⁻(aq) + Ba²⁺(aq) + 2OH⁻(aq) → 2H₂O(l) + Ba²⁺(aq) + 2NO₃⁻(aq) b) HC₂F₃O₂(aq) + OH⁻(aq) → C₂F₃O₂⁻(aq) + H₂O(l)

Write balanced equations of the type indicated for the complete neutralization reactions that occur when the following aqueous solutions are combined: a) complete ionic equation, nitric acid and barium hydroxide b) net ionic equation, trifluoroacetic acid (HC₂F₃O₂) and lithium hydroxide