The three common states of matter are:

1. Gas Gas The three common states of matter are: Indefinite volume Indefinite shape Definite volume Definite shape Definite volume Indefinite shape Liquid Liquid Gas

2. Element, compound, solution or heterogeneous mixture?? 1. One type of atom. Element 2. Sugar dissolved in water. Solution 3. Dirt. Heterogeneous mixture 4. Air. Solution 5. A 24 caret gold ring. Element

3. Element, compound, solution or heterogeneous mixture?? 6. Water. Compound 7. Carbon dioxide gas. Compound 8. An 8 caret gold ring. Solution 9. The contents of your junk drawer. Heterogeneous mixture 10. Ice. Compound

4. Math with Significance 1) 1.0 (1.00+1.000) = 1.0 (2.00) = 2.0 2) (1.000 +1.000)/(0.09 + 0.01) = 2.000/0.10 = 20. 3) 0.50 (2 + 2.0) = 0.50 (4) = 2 4) A rock weighing 7.05 g is dropped into a graduated cylinder containing 5.1 mL of water. What is the density of the rock if the final volume of water is 10.5 mL? D = m/V = 7.05 g/(10.5 mL -5.1 mL) = 7.05 g/5.4 mL D = (1.3055556 g/mL) = 1.3 g/mL

5. For an experiment in which you are determining the freezing point of an unknown chemical, you record the temperature every minute for 20 minutes. In this example, time is the — • A. control C. independent variable • B. dependent variable D. hypothesis 2) In the chemistry lab, chemicals that you are finished working with should be — A. poured into the sink B. returned to their original containers C. mixed together and dumped in a designated container D. disposed of as directed by your teacher

6. 3) In chemistry lab, a student was instructed to find the density of a rectangular piece of aluminum. After careful measurement, he recorded a mass of 31.44 g and a volume of 11.7 cm3. Using the formula density = mass/volume and a calculator, his answer was 2.6871794 g/cm3. Which of these is the correct answer to report for the density of the aluminum? A. 2.7 g/cm3 B. 2.69 g/cm3 C. 2.687 g/cm3 D. 2.68 g/cm3 4) A student told the class that she takes 500 mg of vitamin C every day. What is this mass expressed in grams? A. 0.05 g B. 0.5 g C. 5.0 g D. 500,000 g

7. 5) The table shows the data obtained by four groups of students during a lab investigation designed to determine the boiling point of methanol. The accepted value for the boiling point of methanol is 78.5C. Whose data was the most precise? A. Group A B. Group B C. Group C D. Group D

8. Temperature (°C) Time (minutes) 10 33 20 16 30 8 40 4 50 2 A group of students investigated how temperature affects the rate of chemical reactions. They used hydrogen peroxide, which breaks down into oxygen and water, for their experiment. The students measured how long it took to obtain 50 mL of oxygen gas from a given volume of hydrogen peroxide heated to different temperatures. Their data is shown in the table above. 6) Select the best way for the students to reduce the experimental error in their investigation. A. Test more than one variable at a time. B. Perform repeated trials. C. Change their answers if they do not match their hypothesis. D. Perform the experiment only one time.

9. 7) Characteristics of a substance can be classified as physical properties or chemical properties. Which of the following is a chemical property? A. Boils at 56°C B. Tastes sour C. Has a density of 2.9 g/cm3 D. Reacts with acid to produce hydrogen gas 8) Select the observation that does NOT support the conclusion that a chemical reaction took place. A. Liquid water changed to water vapor. B. A precipitate was formed. C. An odor developed. D. Temperature rose.

10. 9) Reese’s teacher gave her three test tubes, each containing a different unknown liquid sample of a given density. Reese added orange food coloring to each test tube and then calculated the density of the sample. She place the data she collected in the data table. She concluded that the added food color increased the density of the sample. What is another reasonable interpretation of the data? Initial Food Color Final Density Added Density (grams/cm3) (mL) (grams/cm3) Final Color Sample A 0.91 1 1.1 light orange Sample B 0.94 5 1.2 orange Sample C 0.92 7 1.2 blue A. Sample A is a different substance than Sample B. B. Sample C is a different substance than Samples A or B. C. All three samples contain water. D. None of the samples contain water.

11. 10) Which of these is NOT evidence of a chemical reaction? A. An iron nail changes to a brownish-orange color. B. An ice cube melts into liquid water. C. An antacid tablet produces bubbles of gas when placed in water. D. A piece of zinc raises the temperature of an acid as it reacts with it 11) Distillation is a separation technique that involves A. using a porous barrier to separate a solid from a liquid B. separating dissolved substances based on their tendency to be drawn across a surface C. the formation of pure, solid particles of a substance from a solution containing the dissolved substance D. separating two or more liquids based on differences in their boiling points

12. Figure 1 shows a graduated cylinder that contained 25 mL of water. The mass of the cylinder and water was 68.0 g. Fig. 2 shows the same cylinder after a metal sample was lowered into the cylinder. The water level rose to the 30.0 mL mark; the mass of the cylinder, water and sample increased to 77.0 g. 12) What is the identity of the substance? A. iron B. nickel C. titanium D. magnesium

13. 13) There is some error associated with the density calculation of the metal in the cylinder. What is its MOST likely source? A. improperly reading the volume of the sample B. selecting an irregularly shaped metal sample C. selecting the wrong glassware for this measurement D. use of the wrong liquid medium 14) Professor Bothwell determined from the wrapper the number of calories in a candy bar. He then burned the entire candy bar and measured the amount of heat released. His experiment was most likely designed to demonstrate the — A. law of conservation of matter B. law of disorder C. law of conservation of energy D. law of constant composition