Physical Science

1. Physical Science Take 10 Week #15 SPS-4 Periodic Table & SFS- 5 States of Matter

2. Day 1 Question 1 Which of the following changes of state will increase the entropy of water molecules?

3. Day 1 Question 2 Which of the following statements explains what happens to the gas inside a balloon as the external pressure on the balloon decreases and the temperature stays constant? A. The volume increases. B. The volume decreases. C. The molecular speed increases. D. The molecular speed decreases.

4. Day 1 Answers • Which of the following changes of state will increase the entropy of water molecules? Which of the following statements explains what happens to the gas inside a balloon as the external pressure on the balloon decreases and the temperature stays constant? A. The volume increases.

6. Day 2 Question 1 Formaldehyde in solution is used as a preservative. It has a melting point of -92°C. When the temperature of a sample of formaldehyde rises from -93°C to -91°C, which of the following occurs? A. The molecules move more freely. B. The molecules lose electrical charge. C. The molecules break apart into atoms. D. The molecules become fixed in a crystal structure.

7. Day 2 Question 2 A hiker carries drinking water in a cloth-covered, metal container called a canteen. During the summer, the hiker wets the cloth covering so that the water in the canteen stays cool. Which of the following statements explains why a wet covering keeps the water cool? A. A wet covering transfers coolness to the water in the canteen. B. A wet covering insulates the canteen better than a dry covering. C. Evaporation of water from the covering transfers heat away from the canteen. D. Condensation of water from the covering transfers heat away from the canteen.

8. Day 2 Answers 1. Formaldehyde in solution is used as a preservative. It has a melting point of -92°C. When the temperature of a sample of formaldehyde rises from -93°C to -91°C, which of the following occurs? • The molecules move more freely. 2. A hiker carries drinking water in a cloth-covered, metal container called a canteen. During the summer, the hiker wets the cloth covering so that the water in the canteen stays cool. Which of the following statements explains why a wet covering keeps the water cool? C. Evaporation of water from the covering transfers heat away from the canteen.

10. Day 3 Question 1 The diagram below shows two gases maintained at STP in separate chambers by a closed valve. After the valve is opened, the two gases form a homogeneous mixture. Which of the following changes in the system results when forming this mixture? A. loss of heat B. increase in entropy C. chemical reaction of the gases D. decrease in the total volume of the gases

11. Day 3 Question 2 Which of the following statements best explains why water vapor condenses as temperature decreases? A. Collisions between water vapor molecules become elastic. B. Water vapor molecules chemically react when they collide. C. Water vapor molecules are pulled together by the force of gravity. D. Attractive forces between water vapor molecules overcome molecular motion.

12. Day 3 Answers 1. After the valve is opened, the two gases form a homogeneous mixture. Which of the following changes in the system results when forming this mixture? B. increase in entropy 2. Which of the following statements best explains why water vapor condenses as temperature decreases? D. Attractive forces between water vapor molecules overcome molecular motion.

14. Day 4 Question 1 The figure shows part of the periodic table. Which of the following is an accurate comparison of the atomic number and mass of copper (Cu) and gold (Au)? A. Au has a smaller atomic mass and fewer electrons than Cu. B. Au has the same atomic mass as Cu but a greater atomic number. C. Au has the same atomic number as Cu but a much greater atomic mass. D. Au has both a greater atomic number and a greater atomic mass than Cu.

15. Day 4 Question 2 Which of the following correctly describes a trend from top to bottom in the group 2 (2A) elements on the periodic table? • Ionic radius decreases. • Ionic charge increases. C. Atomic radius increases. D. Atomic number decreases.

16. Day 4 Answers 1. Which of the following is an accurate comparison of the atomic number and mass of copper (Cu) and gold (Au)? D. Au has both a greater atomic number and a greater atomic mass than Cu. 2. Which of the following correctly describes a trend from top to bottom in the group 2 (2A) elements on the periodic table? C. Atomic radius increases.

18. Day 5 Question 1 The graph compares three states of a substance. Which of the following choices is the best label for the y-axis? A. molecular density C. neutron density B. molecular motion D. neutron motion

19. Day 5 Question 2 The illustration shows a hot-air balloon. The pilot can change the altitude of the hot-air balloon by changing the temperature of the gas inside the balloon. When the gas is heated, the balloon rises. Which of the following best explains this phenomenon? A. Heating the gas reduces its pressure. B. Heating the gas decreases its density. C. Heating the gas decreases its molecular motion. D. Heating the gas reduces the frequency of the gas molecules’ collisions.

20. Day 5 Answers 1. Which of the following choices is the best label for the y-axis? B. molecular motion 2. Which of the following best explains this phenomenon? B. Heating the gas decreases its density.