SCIENCE HOMEWORK Week Ending 12/10/10

SCIENCE HOMEWORK Week Ending 1/24/12 Answer the following questions on the sheet provided. You MUST TELL WHY you chose the answer!

1. Jennifer wants to know which of three light bulbs last the longest. In her lab journal she writes: The light bulb with the lowest wattage will last the longest.” Which part of the investigation has she written? a. question b. hypothesis c. data analysis d. conclusion

WHY YOU CHOSE YOUR ANSWER?

2. Which part of an experimental design includes the variable that is changed during an experiment?

a. the control group

b. the dependent variable

c. the responding variable

d. the experimental group

3. You are conducting an experiment in which you measure a person’s body temperature in response to changes in air temperature. What is the independent variable that is manipulated during this experiment?

a. air temperature

b. size of the person

c. person’s body temperature

d. size of the room the person is placed in WHY YOU CHOSE YOUR ANSWER?

4. Alison measured the mass of a sample as 3.12 kg. Which is another way to write this measurement? a. 312g b. 3120g c. 312mgd. 3120mg

LITHIUM MEASUREMENTS MASS 5400 mg VOLUME .001 L

5. Maria records the data shown for a sample of lithium, the metal with the lowest density. Based on these data, what is the density of lithium in g/mL? a. .54 g/mL b. 5.4g/mL c. 54 g/mL d. 540 g/Ml

6. Sodium is an element found in table salt. It contains 11 protons and 12 neutrons. How many electrons are found in a neutral atom of sodium a. 11 b. 12 c. 23 d. 1

7. A pure substance that can be separated into two or more simpler substances by chemical means is a. element b. compound c. formula d. atom

8. The chemical formula for glucose is C6H12O6. How many different elements make up one molecule of glucose? a. 1 b. 3 c. 12 d. 24

9. As a substance is changing from a liquid to a gas, the distance between its molecules

a. increases, and the temperature of the system remains the same.

b. Increases, and the temperature of the system decreases.

c. Decreases, and the temperature of the system remains the same.

d. Decreases, and the temperature of the system decreases

10. Which of the following is an example of a chemical change?

a. water evaporating

b. carbon joining with oxygen to form CO2

c. ice cream melting

d. a pencil breaking

WHY YOU CHOSE YOUR ANSWER? 11. Which physical property would be the same as a substance’s melting point?

a. boiling point

b. specific heat

c. freezing point

d. solubility

12. which of the following is the basis for arranging the elements in the modern periodic table? a. alphabetical order b. masses of atoms c. number of protons d. date of discovery

13. What do elements in the same column have in common?

a. similar chemical properties

b. number of protons

c. masses of their atoms

d. size of their atoms

14. Which statement refers to a physical property of a substance?

a. Carbon combines with oxygen to form carbon dioxide. 3 b. The density of copper is 8.93 g/cm .

c. Acids are corrosive.

d. Zinc metal reacts with an acid to produce hydrogen gas.

15. Where are the metalloids located in the periodic table?

a. on the left side

b. in the middle

c. toward the bottom

d. along a zigzag line toward the right side WHY YOU CHOSE YOUR ANSWER?

16. Which is a sign that a chemical change is occurring? a. boiling b. bubbling c. freezing d. melting WHY YOU CHOSE YOUR ANSWER?

17. Baking soda is the common name for the chemical the chemical sodium bicarbonate. The chemical formula for sodium bicarbonate is

NaHCO3. How many different elements are found in this compound? a. 4 b. 5 c. 6 d. 7

18. Which is a mixture? a. liquid nitrogen in a tank b. pure gold c. ocean water d. Table salt (NaCl)

19. Which of the following is an element?

a. NaCl b. Fe3O2 c. OH d. Fe

20. A molecule of hydrogen peroxide is shown. Which of the following shows the correct chemical formula for this molecule?

a. HO b. HO2 c. H2O2 d. H2O