Back Lesson Print Name Class Date Skills Worksheet Concept Review Section: Studying Matter and Energy Answer the following questions in the space provided. 1. What are the fundamental procedures in the scientific method? 2. Why is it important to publish the results of research findings? 3. When performing an experiment, why is it important to have a control? 4. What is a variable? 5. What is the definition of a model? 6. Why are models useful in chemistry? Copyright © by Holt, Rinehart and Winston. All rights reserved. Holt Chemistry 3 Matter and Energy Back Lesson Print Name Class Date Concept Review continued In the space provided at the left of each word or phrase, write the letter of the expression on the right that is most closely related. ______ 7. hypothesis a. a well-tested explanation for a phenomenon based on observation, experimentation, and reasoning ______ 8. theory b. a reasonable and testable explanation of observations ______ 9. scientific law c. The products of a chemical reaction have the same mass as the reactants. ______10. law of conservation of mass d. a description of the natural world that has been proven reliable over time Copyright © by Holt, Rinehart and Winston. All rights reserved. Holt Chemistry 4 Matter and Energy Back Lesson Print TEACHER RESOURCE PAGE Answer Key Concept Review: Energy 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. energy physical chemical endothermic exothermic kinetic transferred In any chemical or physical change, the total quantity of energy remains constant. Energy cannot be created or destroyed. Heat is the enegy transferred between objects that are at different temperatures. Temperature is a measure of how hot or cold something is; specifically, a measure of the average kinetic energy of the particles in a sample of matter. Heat is the energy transferred between objects that are at different temperatures, and temperature is the measurement of the average kinetic energy of the particles in a sample of matter. a. 373.15 K b. 20°C c. 328.15 K d. 185.85°C e. 270.15°C f. 234.15 K Specific heat is the amount of heat required to raise the temperature of 1 g of a substance by 1 K. Substance B will have the higher temperature. Each gram of substance B requires half as much energy to raise its temperature as does substance A. 3. 4. 5. 6. 7. 8. 9. 10. findings to be accepted as valid. The results must be verifiable. A scientist must know for certain that the variable is in fact causing the result to occur and that it would not have happened if the variable had not been changed. A variable is any aspect of an experiment that can be changed to affect the outcome of the experiment. A model is a simplified representation of an object, a system, a process, or an idea. Models are used to represent abstract ideas. A model gives scientists a visual aid so that they may test or envision a smaller or larger-scaled replica of the actual item. b a d c Concept Review: Measurements and Calculations in Chemistry 1. Accuracy is the extent to which a measurement approaches the true value of a quantity; precision is the extent to which a series of measurements of the same quantity made in the same way agree with one another. 2. Answers may vary. Look at the defense of the answer. 3. a. 7 b. unlimited c. 3 d. 10 e. 1 f. 10 g. 1 h. 7 i. 10 j. unlimited 4. These values are not measured; they are counted. They are not subject to measuring inaccuracies. They are exact. Concept Review: Studying Matter and Energy 1. observing, formulating hypotheses, testing hypotheses, analyzing results, drawing conclusions, publishing results 2. The research findings of any experiment or investigation must be reproducible by other scientists for those Copyright © by Holt, Rinehart and Winston. All rights reserved. Holt Chemistry 109 Matter and Energy