Exam #2A multiple choice

Which of the following gas has higher density at STP condition? A. CH4 B. Cl2 C. CO2 D. O2

B Cl2 has highest molecular weight = 71.0 gr/mol

This fossil fuel was formed from the remains of plants that were buried and exposed to high pressure and heat over time. A. coal B. natural gas C. diesel fuel D. propane E. gasoline

A. coal

Which of the following are nonelectrolytes in water? (i) HF (ii) ethanol, C2H5OH (iii) CH3 OCH3 (iv) KClO3 A. ii and iii B. i, ii, and iii C. iii only D. ii only

A. ii and iii

Which of the following does not have a standard enthalpy of formation equal to zero at 25°C and 1.0 atm? A. F2(g) B. Al(s) C. H2O(l) D. H2(g) E. They all have a standard enthalpy equal to zero.

C. H2O(l)

Which of the following is a weak base? A. NaOH B. Ca(OH)2 C. NH4OH D. RbOH

C. NH4OH

Which of the following is/are not characteristic of gases? I. high density II. formation of homogeneous mixtures III. low intermolecular forces A. I only B. I and III C. I, II, and III D. II and III

A. I only

From the following heats of reaction, 2C (graphite) + H2 (g) --> C2H2 (g) ∆ H = 227 kJ/mole 6C (graphite) + 3H2 (g) --> C6H6 (l) ∆ H = 49 kJ/mole calculate the heat for the reaction 3C2H2 (g) --> C6H6 (l) A. 632 kJ/mole B. -632 kJ/mole C. -178 kJ/mole D. 178 kJ/mole

B. -632kJ/mole

For a particular process q = - 17 kJ and w = 21 kJ. Which of the following statement is false? A. Heat flows from the system to the surroundings B. The system does work on the surroundings C. ∆E = + 4 kJ D. The process is exothermic E. None of the above is false

C ( should be ΔE = +4 kJ)

How many moles of N2 gas occupy 11.2 liters volume a STP condition? A. 1.0 mol B. 2.0 mol C. 0.50 mol D. cannot be determine

C (11.2 L) ( 1 mol / 22.4 L) = 0.50 mol N2

An unknown gas "X" effuses two times faster than a sample of SO3(g) through a porous container. Which of the following is the unknown gas ? A. H2 B. CH4 C. Ne D. Ar

C rate(X) / rate (SO3) = ( MSO3/Mx)½ --> 2 = ( 80 / Mx)½ --> 4 = 80 / Mx --> Mx = 80/4 = 20 Neon

The heat of combustion of fructose, C6H12O6, is -2812 kJ. Using the following information, calculate ∆H°f for fructose. C6H12O6 (s) + 6O2(g) --> 6CO2(g) + 6H2O (l) ∆ H°f ( CO2 ) = -393.5 KJ/mole ∆ H°f (H2O) = - 285.83 KJ/mole A -210.3 kJ/mol B. 210.3 kJ/mol C. -1264 kJ/mol D. 1264 kJ/mol

C. -1264 kJ/mol ∆ H = ∆ H°f (reactants0 - ∆ H°f (products) -2812 = [6(-285.83) + 6(-393.5)] - [ 6 (0) + ∆ H°f (fructose)] --> ∆ H°f (fructose)= -1264 kJ/mol

Consider the reaction: C2H5OH(l)+3O2(g)-->2CO2(g)+3H2O(l), ∆H= -1.37x10^3kJ When a 21.1-g sample of ethyl alcohol (molar mass = 46.07 g/mol) is burned, how much energy is released as heat? A. 0.458 kJ B. 0.627kJ C. 6.27x10^2 kJ D. 2.89x10^4 kJ E. 2.18kJ

C. 6.27x10^2 kJ

According to the first law of thermodynamics, the energy of the universe is constant. Does this mean that ∆E is always equal to zero? A. Yes, ∆E = 0 at all times, which is why q = -w. B. No, ∆E does not always equal zero, but this is only due to factors like friction and heat. C. No, ∆E does not always equal zero because it refers to the system's internal energy, which is affected by heat and work. D. No, ∆E never equals zero because work is always being done on the system or by the system E. No, ∆E never equals zero because energy is always flowing between the system and surroundings.

C. No, ∆E does not always equal zero because it refers to the system's internal energy, which is affected by heat and work.

Which of the following is not a statement of Boyle's law? All statements assume constant temperature and amount of gas. A. P = constant/V B. V α 1/P C. P/V = constant D. PV = constant

C. P/V = constant

4. Which of the following reactions will occur? (i)Ni(s) + Zn2+(aq) (ii)Pb(s) + Ag+(aq) (iii)Zn(s) + Ca2+(aq) (iv)Al(s) + Fe2+(aq) A. i only B. ii only C. ii and iv only D. i and iii only

C. ii and iv only

Calculate the work for the expansion of CO2 from 1.0 to 4.7 liters against a pressure of 1.0 atm at constant temperature. A. 3.7 L·atm B. 4.7 L·atm C. 0 L·atm D. -3.7 L·atm E. -4.7 L·atm

D. -3.7 L·atm

How many kJ of heat must be removed from 1.0x103 g of water (heat capacity of 4.184 J /g.K) to lower the temperature from 18.0°C to 12.0°C? A. 2.5x10-2 kJ B. 1.4 kJ C. 4.2 kJ D. 25 kJ

D. 25 kJ q = m.s . ∆T = (1.0x103 g)(4.184 J/g.K)( 18.0 - 12.0 oC) = 25104 J = 25100 J /1000 = 25 kJ

How many milliliters of 1.50 M KOH solution are needed to supply 0.125 mole of KOH? A. 0.0833 ml B. 0.188 ml C. 12.0 ml D. 83.3 ml

D. 83.3 ml

Which of the following is/are soluble in water? (i) NiCl2 (ii) Ag2S (iii) Cs3PO4 (iv) (NH4)2SO4 A. iv only B. i, ii, and iii C. i, ii, and iv D. i, iii and iv

D. i, iii and iv

The following statements concerning petroleum are all true except: A. It is a thick, dark liquid composed mostly of hydrocarbons. B. It must be separated into fractions (by boiling) in order to be used efficiently. C. Some of the commercial uses of petroleum fractions include gasoline and kerosene. D. It was probably formed from the remains of ancient marine organisms. E. All of its hydrocarbon chains contain the same number of carbon atoms.

E. All of its hydrocarbon chains contain the same number of carbon atoms.