Start learning →

AP Intermediate 1st Year Chemical Changes, Reactions & Atmospheric Pollution — practice questions — page 2

Explore 47 free Chemical Changes, Reactions & Atmospheric Pollution questions in AP Intermediate 1st Year Chemistry. Open each question or exercise to read its content, reference answers and available explanation.

Practise Chemical Changes, Reactions & Atmospheric Pollution with Quill →

Chemical Changes, Reactions & Atmospheric Pollution questions and exercises with answers

Showing questions 31–47 of 47.

A heat engine takes in 6.0 kJ of heat and produces 4.8 kJ of waste heat. What is its efficiency?Read the answer and worked solution →A coal power station operates at 40.0 percent efficiency and takes in 1.20 x 10^12 J by heat. How much work does it do?Read the answer and worked solution →A coal power station transfers 3.0 x 10^12 J by heat from burning coal and releases 1.5 x 10^12 J by heat into the environment. What is its efficiency?Read the answer and worked solution →In the heat pump described, which component raises the temperature and pressure of the working fluid using electrical work?Read the answer and worked solution →What condition would be required for a heat engine to reach 100 percent thermal efficiency?Read the answer and worked solution →A process spontaneous in one direction under given conditions is, in reverse:Read the answer and worked solution →A specific configuration of all the locations and energies of a system's particles is a:Read the answer and worked solution →Who developed the molecular-scale statistical model relating entropy to microstates?Read the answer and worked solution →The second law of thermodynamics states that all spontaneous changes cause an increase in:Read the answer and worked solution →When the entropy change of the universe is zero, the system is:Read the answer and worked solution →Who introduced the thermodynamic property defined in terms of system properties only?Read the answer and worked solution →In thermodynamics, a reversible process is one that takes place at a rate that is:Read the answer and worked solution →A pure, perfectly crystalline solid at absolute zero is described by how many microstates?Read the answer and worked solution →At absolute zero a perfect crystal has only one microstate because there is:Read the answer and worked solution →The standard entropy change for a reaction is computed using standard entropies and:Read the answer and worked solution →Besides indicating spontaneity, the free energy change gives information about the amount of:Read the answer and worked solution →Free energy is described as the energy available to do useful work, being the difference between:Read the answer and worked solution →

Worked practice questions

A heat engine takes in 6.0 kJ of heat and produces 4.8 kJ of waste heat. What is its efficiency?

  1. 20 percent
  2. 25 percent
  3. 48 percent
  4. 80 percent
Show answer and solution

Correct answer: A. 20 percent

1. Work output is W = Qh minus Qc = 6.0 kJ minus 4.8 kJ = 1.2 kJ. 2. Efficiency is Eff = W divided by Qh = 1.2 divided by 6.0. 3. Dividing gives Eff = 0.20, or 20 percent. 4. 80 percent is the fraction of heat wasted, not the efficiency, and 48 or 25 percent do not match this division. 5. So 20 percent is correct. _Source: OpenStax Physics (CC BY 4.0), Ch 12 "Thermodynamics", section 12.4 Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators_

Open this question →

A coal power station operates at 40.0 percent efficiency and takes in 1.20 x 10^12 J by heat. How much work does it do?

  1. 3.0 x 10^10 J
  2. 4.8 x 10^11 J
  3. 3.0 x 10^12 J
  4. 4.8 x 10^13 J
Show answer and solution

Correct answer: B. 4.8 x 10^11 J

1. Efficiency is Eff = W divided by Qh, so work output is W = Eff multiplied by Qh. 2. Substitute Eff = 0.400 and Qh = 1.20 x 10^12 J. 3. Multiplying gives W = 0.400 x 1.20 x 10^12 = 4.8 x 10^11 J. 4. 3.0 x 10^12 J and 4.8 x 10^13 J are far too large for a 40 percent share of the input heat. 5. 3.0 x 10^10 J is too small by more than an order of magnitude. 6. So 4.8 x 10^11 J is correct. _Source: OpenStax Physics (CC BY 4.0), Ch 12 "Thermodynamics", section 12.4 Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators_

Open this question →

A coal power station transfers 3.0 x 10^12 J by heat from burning coal and releases 1.5 x 10^12 J by heat into the environment. What is its efficiency?

  1. 0.33
  2. 0.50
  3. 0.66
  4. 1.00
Show answer and solution

Correct answer: B. 0.50

1. Efficiency is Eff = W divided by Qh, where W = Qh minus Qc. 2. First find the work: W = 3.0 x 10^12 J minus 1.5 x 10^12 J = 1.5 x 10^12 J. 3. Then Eff = 1.5 x 10^12 divided by 3.0 x 10^12. 4. Dividing gives Eff = 0.50. 5. 0.33 and 0.66 do not match this division, and 1.00 would mean no heat at all was rejected to the environment. 6. So 0.50 is correct. _Source: OpenStax Physics (CC BY 4.0), Ch 12 "Thermodynamics", section 12.4 Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators_

Open this question →

How to practise

  1. Choose a Chemical Changes, Reactions & Atmospheric Pollution question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

Put it into practice

Continue with Chemical Changes, Reactions & Atmospheric Pollution practice for AP Intermediate 1st Year. Read explanations as you go. No signup form needed to start.

Practise Chemical Changes, Reactions & Atmospheric Pollution →

More Chemistry topics

Structure of AtomEquilibriumChemical Bonding and Molecular StructureRedox ReactionsClassification of Elements and Periodicity in PropertiesHydrocarbonsSome Basic Concepts of ChemistryOrganic Chemistry: Some Basic Principles and Techniques