Big Idea #5 Test

How much energy is required to melt 64 g of methane at 90 K? (MM of Methane is 16g/mol)

3.8 kJ

How much heat is released or absorbed when a 0.050 mol of Cl2(g) is formed from KCl?

43.7 kJ is absorbed

N2(g) + 3H2(g) ---> 2NH3(g) The reaction indicated above is thermodynamically spontaneous at 298 K, but becomes nonspontaneous at higher temperatures. Which of the following is true at 298 K?

G, H, and S are all negative

It is observed that the reaction producing KCl (s) from its elements goes essentially to completion. Which of the following is a true statement about the the thermodynamic favorability of the reaction

The reaction is favorable and driven by and enthalpy change only

The process of dissolution of NaCl(s) in H2O(l) is represented in the diagram above. Which of the following summarizes the signs of H and S for each part of the dissolution process?

+ + + + - +

Which of the following equations represents a reaction for which the standard entropy change is positive (S>0)?

CaCO3(s) -----> CaO(s) +CO2(g)

When 5.0 g of NH4ClO4(s) is added to 100. mL of water in a calorimeter, the temperature of the solution formed decreases by 3.0 C. If 5.0 g of NH4ClO4(s) is added to 1000. mL of water in a calorimeter initially at 25.0 C, the final temperature of the solution will be approximately

24.7 C

I2(g) + 3Cl2(g) ----> 2ICl3(g) According to the data in the table below, what is the value of the H for the reaction represented above?

-382 kJ

Assume that the bond enthalpies of the oxygen-hydrogen bonds in H2O are not significantly different from those in H2O2. Based on the value of H of the reaction, which of the following could be the bond enthalpies (in kJ/mol) for the bonds broken and formed in the reaction?

150 500 500

A 100g sample of a metal was heated to 100 C and then quickly transferred to an insulated container holding 100g of water at 22 C. The temperature of the water rose to reach a final temperature of 35 C. Which of the following can be concluded?

The metal temperature changed more than the water temperature did, but the metal lost the same amount of thermal energy as the water gained

3C2H2(g)--->C6H6(g) What is the standard enthalpy change, H, for the reaction represented above ?

-607 kJ

What is the value of the enthalpy change per mole of HCl(g) produced?

-93 kJ

Based on the thermodynamic data, which of the following is true at 298 K?

0<Keq<1

Based on the bond energies listed in the table above, which of the following is closest to the bond energy of the C-N bond?

300 kJ/mol

A hot iron ball is droped into a 200. g sample of water initially at 50 C. If 8.4 kJ of heat is transferred from the ball to the water, what is the final temperature of the water (The specific heat of water is 4.2 J/(g. C).)

60. C

For which of the following processes would S have a negative value? II. Mg2+ +2OH- --->Mg(OH)2(s) III. H2(g) + C2H4(g) -----> C2H6(g)

II and III only

Which of the following processes results in an increase in entropy of the system? All systems are closed systems II. NaBr(s)----->Na+(aq) + Br-(aq) V. C6H6(g)---> 3C2H2(g)

II, V

Which of the following best explains why more energy is required for the process occurring at 110 K than for the process occurring at 90 K

Intermolecular attractions are completely overcome during vaporization

Under which of the following temperature conditions is the reaction thermodynamically favored?

It is not favored at any temperature

Based on the information above, which of the following expressions represents the equilibrium constant, K, for the reaction represented by the equation below? La+3 + CO3 -2 ---> LaCO+3

K=(K1)(Kw)/(Ka)

What remains in the reaction vessel after equal masses of K(s) and Cl2(g) have reacted until either one or both of the reactants have been completely consumed?

KCl and Cl2 only

The enthalpy of vaporization of water is 40.7 kJ/mol. Which of the following best explains why the enthalpy of vaporization of methane is less than that of water?

Methane does not exhibit hydrogen bonding, but water does

When solid Ammonium chloride, NH4Cl(s), is added to water at 25 C, it dissolves and the temperature of the solution decreases. Which of the following is true for H and S for the dissolving process?

Positive, Positive

CO(g) + 2H2 -----> CH3OH(g) H < 0 Which of the following statements is true about bond energies in this reaction?

The energy absorbed as the bonds in the reactants are broken is less than the energy released as the bonds in the product are formed

The heating curve fro a sample of pure ethanol is provided above. The temperature was recorded as a 50.0g sample of solid ethanol was heated at a constant rate. Which of the following explains why the slope of segment T is greater than the slope of segment R?

The specific heat capacity of the gaseous ethanol is greater than the specific heat capacity of liquid ethanol.

A 10. g cube of copper at a temperature T1 is placed in an insulated cup containing 10. g of water at a temperature T2. If T1>T2, which of the following is true of the system when it has attained thermal equilibrium? (The specific heat of copper is .385 J/(g. C) and the specific heat of water is 4.18 J/(g. C).)

The temperature of the copper changed more than the temperature of the water

Which of the following statements identifies the greatest single reason that the value of Kp for the overall reaction at 298 K has such a large magnitude?

The value of H for the overall reaction is large and negative

Cl2(g) + 2e- ----> 2Cl-(g) Which of the following expressions is equivalent to H for the reaction represented above?

x + 2y

Which of the values of H for a process in the table is (are) less than zero (i.e. indicates and exothermic process)

y and z only

Based upon the information above, what is the standard enthalpy of change for the following reaction? Na2O(s) + H2O(l)----> 2NaOH(s)

-150 kJ