Chemistry Study Guide

1. What is Chemistry? The study of the composition, structure, and properties of matter. The processes that matter undergoes and the energy changes that accompany these processes. 2. What is the formula for density? If I give you the density of a substance and the volume, you should be able to tell me the mass… Density = Mass/Volume 3. Compare and contrast intensive and extensive properties. Give an example of each. Extensive properties depend on the amount of matter that is present. Such properties include volume, mass, and the amount of energy in a substance. Intensive properties DO NOT depend on the amount matter present. Such properties include the melting point, boiling point, density, and ability to conduct electricity and to transfer energy as heat. 4. How many significant figures do the following numbers have? a. .0023- 2 b. 2004- 4 c. 2.34000- 6 d. 2000- 1 5. What is the importance of significant figures? Significant figures in a measurement consist of all the digits known with certainty, plus one final digit, which is somewhat uncertain of is estimated. 6. What is the difference between precision and accuracy? Precision refers to the closeness of a set of measurements made in the same way. Accuracy refers to the closeness of measurements to the correct of accepted value of the quantity measured. 7. What is the difference between a homogenous and a heterogeneous mixture? Give an example of each. Homogenous mixtures are uniform in composition; an example would be salt water. Heterogeneous mixtures are not uniform throughout; an example would be clay & water. 8. 6.23 L = 6230 mL (be sure you know the metric system and order) 9. Compare and contrast mass and weight. Mass is a measure of the amount of matter, mass is the measurement you make using a balance. Matter can thus be defined as anything that has mass and takes up space. 10. What are the steps of the scientific method? Observing,