Lesson: Chapter - 9

Enthalpy:Practice Questions


1. Statement I Statement II
The reaction shown above is exothermic. BECAUSE   The total enthalpy of the products in this reaction is less than that of the reactants.
2. Use the bond energies given below to estimate the enthalpy, DH, for the following reaction:

(A) DH = -800 kJ
(B) DH = -680 kJ
(C) DH = -150 kJ
(D) DH = +150 kJ
(E) DH = +200 kJ
3. Each of two solutions are mixed separately, and both solutions are found to be the same temperature. The two solutions are mixed, and a thermometer shows that the mixture’s temperature has decreased in temperature. Which of the following statements is true?
(A) The chemical reaction is exothermic.
(B) The chemical reaction is absorbing energy.
(C) The chemical reaction is releasing energy.
(D) The energy released could be found by multiplying the temperatures together.
(E) The energy absorbed by the solution is equal to the difference in temperature of the solutions.
4. Consider the reaction below. When a 45.00 gram sample of ethanol is burned with excess oxygen, about how much energy is released as heat?
C2H5OH(l) + 3O2(g) ? 2CO2(g) + 3H2O(l) ?H = -1.40 × 103 kJ
(A) 0.995 kJ
(B) 5.1 × 102 kJ
(C) 1.40 × 103 kJ
(D) 2.80 × 103 kJ
(E) 5000 kJ
5. In neutralizing 500 mL of 1.0 M HCl with 500 mL of 1.0 M NaOH, the temperature of the solution rises 5.0ºC. Given that the density of the solution is 1.0 g/mL and the specific heat of the solution is 4.184 J/g ºC, calculate the approximate energy released from this experiment.
(A) 20 J
(B) 1000 J
(C) 4200 J
(D) 2.1 × 104 J
(E) 1.0 × 104 kJ
6. Based on the relationship of entropy to the degree of disorder of a system, which response includes all the occurrences listed that represent a decrease in entropy?
  I. The freezing of water  II. The vaporization of water III. Sublimation (vaporization) of dry ice, solid CO2 IV. The extraction of Mg and pure water from seawater
(A) I and II
(B) II and IV
(C) I and IV
(D) III
(E) II and III
7. Spontaneous reactions are driven by
(A) Low enthalpy values and high entropy values
(B) Low enthalpy values and low entropy values
(C) High enthalpy values and low entropy values
(D) High enthalpy values and high entropy values
(E) High temperatures and low pressures
8. If an exothermic process is spontaneous, which of the following statements must be true?
(A) DG must be positive.
(B) DS must be positive.
(C) DS must be negative.
(D) The temperature must be over 500K.
(E) DG must be negative.
9. Consider the following hypothetical reaction (at 375K). The standard free energies in kJ/mol are given below each substance in parentheses.What is the value of the Gibb’s free energy for the reaction at this temperature? Is the reaction spontaneous?
(A) -220; yes
(B) -180; no
(C) -160; yes
(D) +180; no
(E) -160; no
10. Which of the following events is least likely to occur with an increase in temperature for the reaction given? (WithH= -45.9 kJ/mol.)
N2+3H2 ?3NH3
(A) The gas particles will move more quickly.
(B) The reaction will produce more ammonia in a shorter time.
(C) The reaction will reverse and ammonia will decompose.
(D) The entropy of the system will increase.
(E) The equilibrium constant will become smaller.
Back Next

Next to display next topic in the chapter.

Practice Questions

Test Prep Lessons With Video Lessons and Explained MCQ

Large number of solved practice MCQ with explanations. Video Lessons and 10 Fully explained Grand/Full Tests.

Quantitative Aptitude Reasoning English General Knowledge Picture Patterns
More for You
MCQ with question Explanations Scholarships and Financial Aid

GMAT Preparation

GAMT preparation paper-base and online

Sentence Completion

Learn to crack Sentence Completion section of the test

Chemistry for Test Preparation

Lessons with Practice questions -MCQs for Chemistry for Test preparation

All in this Category

You may be interested in

Colleges in Dera ismail khan

Find major schools in your location ...

Colleges in cities of Punjab

Comprehensive lists of colleges in ...

Study in Turkey

How to get admission and Visa to st ...

Study in India

Have an opportunity to study in an ...

GMAT CAT

What is GMAT CAT? How to deal with ...

ISSB Direction Sens Questions

Learn about ISSB Direction Sens Que ...

LUMS - Business Degrees

LUMS: Lahore University of Manageme ...

SAUT Sindh Agriculture University

A popular agri univerist in Sindh i ...

About us

EntryTest.com is a test preparation service for students seeking successful career.

About Disclaimer

Quick Test Prep

NUST NET IBA Karachi SAT LUMS LCAT LSE

 

NTS GAT NTS NAT GMAT GRE ACT

Study Abroad

Education Abroad Business Schools MS in USA