GED Practice

GED Science Review: Temperature and Heat

Questions:

Directions: Choose the answer to each question.


Questions 1 refer to the following passage and diagram.

          The transfer of heat from one object to another can be explained in terms of moving molecules. The molecules in hot objects have more kinetic energy and move faster than the molecules in cold objects. This molecular motion is measured as temperature. When two objects come in contact with each other, the higher-energy molecules in the warmer object begin to collide with the molecules in the cooler object. Energy is transferred in the process. This model shows that coldness is actually the absence of heat. As heat energy leaves an object, the object becomes less warm, or colder.



  1. As an ice cube in your hand melts, your hand begins to feel cold, Which of the following conclusions about heat transfer is supported by the information in the passage and the diagram?
    • The temperature of the ice decreases.
    • Cold from the ice flows into your hand.
    • The molecules in your hand gain energy.
    • Heat from your hand is absorbed by the ice.
  2. Which statement best predicts what will happen after the objects in contact reach the same temperature?
    • Heat will no longer be transferred from one object to the other.
    • Temperature will no longer depend on the motion of molecules.
    • The object on the right will continue to gain heat and become warmer.
    • The temperature of both objects will increase as heat is transferred from the air.
  3. Heat energy can be transferred in three ways. In convection, heat is transferred by the flow of currents through gases and liquids. In conduction, heat is transferred from molecule to molecule. In radiation, heat is transferred by electromagnetic waves, which can travel through space.



    Questions 4 and 5 refer to the following passage and graphs.

    All substances have a form of stored energy called chemical potential energy. In a chemical reaction, substances called reactants change to produce different substances, products. Energy changes involve breaking and re-forming the bonds that make up these substances. Therefore, the amount of chemical potential energy in the products differs from that in the reactants.
    In an endothermic chemical reaction, more energy is needed to break the bonds in the reactants than is released by forming bonds in the products. This energy may come from the surroundings. In an exothermic reaction, the energy released as the products form is greater than the energy absorbed to break the bonds in the reactants. The graphs show how chemical potential energy changes as these reactions proceed.


     
  4. Which change occurs during an endothermic chemical reaction?
    • Energy is created.
    • Energy is released.
    • Energy is absorbed.
    • Energy is destroyed.
  5. A scientist carries out a reaction in a test tube. After the reaction stops, she notices that the test tube is very warm. What can be concluded about this reaction?
    • The reactants absorb heat energy from their surroundings.
    • The energy of the products is equal to the energy of the surroundings.
    • The produces require more energy to form than is released by the reactants.
    • The chemical potential energy of the reactants is more than that of the products.


  6. Temperatures can be measured on different scales. The table shows the same temperatures on the Fahrenheit scale, the Celsius scale, and the Kelvin scale.

    Coffee is often brewed at 170˚F. How is this temperature expressed on the Celsius scale and the Kelvin scale?
    • 40˚C and 375 K
    • 77˚C and 350 K
    • 105˚C and 445 K
    • 395˚C and 605 K36
Answer:

  1. Heat from your hand is absorbed by the ice.
  2. Heat will no longer be transferred from one object to the other.
  3. radiation; convection
  4. Energy is absorbed.
  5. The reactants absorb heat energy from their surroundings.
  6. 77˚C and 350 K






Reference:


Complete Test Preparation for the GED Test 2014 by Steck-Vaughn