Multiple Choice Practice. Answer in the blank (If not in the blank and LEGIBLE, it will not be graded.) While it will not be graded, it is required that you write a sentence with the logic for your answer for each question. Questions without the explanation will not be given credit. _b__ 1. Which of the following is a heterogeneous mixture? a. peanut butter cookie b. frosted sugar cookie c. unfrosted sugar cookie d. all are heterogeneous e. none are heterogeneous The frosting and the cookie represent two separated phases. _a__ 2. Why are the phrases “heterogeneous” and “homogeneous” not used to describe pure substances? a. All pure substances are homogeneous by their nature b. All pure substances are heterogeneous by their nature c. These are nouns and not descriptive adjectives d. Those terms are used for pure substances, why are you trying to trick me? Since they are all the same thing (pure) it must look the same throughout. __c_ 3. Which of the following is an appropriate unit to measure the length of the infamous palmetto bug (see Figure 1)? a. mg b. km c. cm d. µg Grams are units of mass, not of length. A kilometer is longer than even the scariest Augusta bug! Figure 1
__e_ 4. Density is best described as a a. physical property b. chemical property c. extensive property d. intensive property e. both physical and intensive property f. both a chemical and intensive property As it does not vary with amount, it is intensive. As it does not require a change in identity to observe, it is physical. __a__ 5. What does the picture in Figure 2 represent? a. homogeneous mixture of elements b. homogeneous mixture of compounds c. homogeneous mixture of an element and a compound d. heterogeneous mixture of elements Figure 2
e. heterogeneous mixture of compounds f. heterogeneous mixture of an element and a compound Elements are made of molecules that are the same type. There are two different types of substances (so a mixture), but each group consists of the same atoms. There is no part of the container where one type of substance congregates, so homogeneous is the best description. __c__ 6. What does the picture in Figure 2 represent? a. solid b. liquid The molecules are not next to each other, so it is a gas. c. gas d. more than one phase __d__ 7. In which of the following are molecules adjacent (touching) each other? a. solid b. liquid c. gas d. both solid and liquid e. both liquid and gas f. both solid and gas g. solid, liquid and gas Molecules are far apart in gases. That is why they have a low density and are compressible. __a__ 8. When you add 1.56 m + 3.6 m, what are the units on the final answer? a. meters b. meters squared c. it’s unitless d. mm When you add measurements, each value should have the same units and the answer will have the same units as the measurement. “m” is the symbol for meters. __c__ 9. When you multiply 2.44 cm2 times 5.6 g/cm3, the units on the final answer are a. cm2 b. g/cm2 c. g/cm d. g/cm3 e. g/cm5 f. can’t do it 2
When you multiply, you treat units as variables. Since cm is on the top of the fraction (it would say 1/cm2 or cm‐2 if it were on the bottom) and cm3 is on the bottom (it does have a /cm3 !), two of the cm’s cancel, leaving one left. The grams part is not affected. ______ 10. What is the name of your professor? a. Ms. Meyers b. Dr. Myers c. Dr. Meyer d. Mr. Samarakoon e. Dr. Samarakoon f. Ms. Samarakoon Sections A,B,C = Dr. Myers Sections G, H = Dr. Samarakoon Yes, it is important. Knowing the proper form of address shows respect and a knowledge of what is appropriate in each situation (i.e., professional behavior)…which is a good life skill!