Vocabulary
Select the correct term to complete the sentences.
Section 4.1
1. The mass of matter per unit of volume is known as ____.
2. The upward force exerted by a fluid on an object submerged in the fluid is called ____.
3. The idea that the buoyant force exerted on an object is equal to the weight of the fluid displaced by the object is known as____.
4. The force exerted on an object by the gravity of Earth is called ____.
Concepts
Section 4.1
1. Which has a greater weight, 1.0 gram of steel or 1.0 gram of aluminum?
2. Which has a greater density, 1.0 gram of steel or 1.0 kilogram of aluminum?
3. Which has a greater volume, 1.0 gram of steel or 1.0 gram of aluminum?
4. Name three units that can be used to represent density.
5. When comparing solids, liquids, and gases:
a. Which phase generally has the greatest density?
b. Which phase has the lowest density?
6. The density of ice is less than the density of water. How doesthis affect life in a pond over a long, cold winter?
7. Using Table 4.1 on page 75, which material might be used to make an object with a density of 0.60 g/cm3?
8. A glass block has a density of 2.7 g/cm3. If the same type of glass was used to make a 2-liter water pitcher, what would be the density of the pitcher?
9. By adding more lead to a bar of lead you:
a. increase the bar’s density.
b. decrease the bar’s density.
c. do not change the bar’s density.
10. If you know the mass and density of a material, how would you find its volume?
11. Based upon the diagram to the right, arrange the three materials, cork, water, and lead in order from most to least dense.
12. A graduated cylinder contains 25 mL of water. An object placed in the cylinder causes the water level to rise to 43 mL. What is the volume of the object?
13. What is the name of the dark, curved “band” at the top of the column of water pictured in the graduated cylinder to the right?
Section 4.2
14. How does the buoyant force of a rock submerged in water compare to the weight of the water displaced by the rock?
15. Why does ice float in a glass of water? Explain in terms of density and buoyancy.
16. What property of an object determines the strength of buoyant force that will be exerted on it when submerged in water?
17. A cargo barge weighs 200,000 N when empty. Cargo weighing 50,000 N is loaded onto the barge. What is the total weight of water displaced by the loaded barge?
18. What is the maximum average density that a fully loaded cargo ship may have?
19. Why do helium balloons float in air? Use the terms buoyancyand density in your answer.
Problems
Section 4.1
1. A piece of granite has a mass of 26 grams. The granite is placed in a graduated cylinder containing 10 mL of water.
What is the reading of the water level in the graduated cylinder after the granite is fully submerged? Granite has a density of 2.6 g/cm3.
2. Convert a density of 123 kg/m3 to units of g/cm3.
3. What is the volume of the liquid in the graduated cylinder pictured in the diagram?
4. A rubber ball has a radius of 2.5 cm. The density of rubber is 1.2 g/cm3.
a. What is the volume of the ball?
b. What is the mass of the ball?
5. The density of ice is 0.92 g/cm3. What is the volume of 1 kg of ice? If that 1 kg of ice completely melted, what would the volume of water be? The density of water is 1 g/cm3.
6. Your teacher gives you two stainless steel balls. The larger has a mass of 25 grams and a volume of 3.2 cm3. The smaller has a mass of 10 grams. Calculate the volume of the smallerball.
7. The cube in the diagram has a mass of 7.8 grams and measures 1.2 centimeters on an edge.
a. Find the density of the cube. Show your work, including an equation.
b. Will the cube float in water? Explain.
Section 4.2
8. An object weighing 45 newtons in air is suspended from a spring scale. The spring scale reads 22 newtons when the object is fullly submerged. Calculate the buoyant force on the object.
9. A stone that weighs 6.5newtons in air weighs only 5.0 newtons when submerged in water. What is the buoyant force exerted on the rock by the water?
10. A 100 mL oak object is placed in water. What volume of water is displaced by the oak object? The density of oak is 0.60 g/cm3.
11. A 100 mL steel object is placed in water. What volume of water is displaced by the steel object? The density of steel is 7.8 g/cm3.
Chapter 5 Assessment
Vocabulary
Select the correct term to complete the sentences.
Section 5.1
1. When a substance changes from gas to liquid at a temperature below its boiling point, ____ has taken place.
2. The temperature at which a substance changes from liquid to gas is its ____.
3. The transfer of heat through the motion of fluids such as water or air is known as ____.
4. A scientist would call the change of a substance from liquid to gas at a temperature below its boiling point ____.
5. The temperature at which a substance changes from solid to liquid is its ____.
6. A form of matter that flows when any force is applied to it is called a(n) ____.
7. A force that acts in all directions and comes from the constant collisions of many atoms is ____.
8. ____ are what hold water molecules together in liquid water and in ice.
Section 5.2
9. Transfer of heat by direct contact between particles ofmatter is called ____.
10. A solid whose atoms are arranged in an orderly, repeating pattern would be called a ____ solid.
11. When heat does not transfer from one object to another because both objects are at the same temperature, the condition is called ____.
12. The ability to bend without breaking is known as ____.
13. Solids whose atoms or molecules have no orderly, repeating pattern are called ____ solids.
14. ____ is a solid’s ability to be stretched and then return to its original size.
15. The tendency of a solid to crack or break before stretching very much is known as ____.
16. The ability of an object to maintain its shape even when force is applied is ____.
Concepts
Section 5.1
1. For each phase or form, identify the matter as liquid (L), gas (G), or both (B):
a. ____ definite volume but changes shape to fit the shapeof the container.
b. ____ generally has the lower density of the two forms.
c. ____ expands to completely fill any container.
d. ____ bonds between atoms are not completely broken.
e. ____ may be called a fluid.
f. ____ molecules of this form have more energy.
g. ____ force exerted on this form is transmitted aspressure in all directions.
2. Explain what causes pressure in a fluid on a microscopic level. In what direction does the pressure act on the fluid?
3. Describe the two types of forces that act between atoms.
4. Use the words attractive and repulsive to make the following statements true:
a. At distances greater than the size of the molecules, intermolecular forces are ____.
b. Once molecules are close enough to touch, intermolecular forces become ____.
5. What is the result of intermolecular forces being repulsive and attractive at varying distances?
6. How do thermal energy and intermolecular forces behave with each other?
7. What phase of matter has a low amount of thermal energy, which allows the intermolecular forces to dominate?
8. The solid, liquid, and gaseous phases of a material each have different strengths of intermolecular force compared to the amount of thermal energy. For each diagram below, rank as low, medium, or high:
a. the amount of intermolecular force, and
b. the amount of thermal energy
9. Name one factor that causes iron to have a higher boiling point than water.
10. As heat energy is added to ice, the temperature increases until it reaches 0°C. What happens at this point and why?
11. Why is ice less dense than water?
12. Why is oxygen transported as a liquid in rocket ships instead of as a gas?
13. How does the evaporation of sweat on a hot day help to cool your body?
14. If a meterologist describes the air as saturated, what does he or she mean?
15. Give one example of natural convection.
16. What type of heat transfer is represented in the diagram below?
17. From where does the carbon in a tree come from?
18. What two gases make up the majority of the atmosphere?
19. How does rain form?
Section 5.2
20. Why can solid materials hold their shape?
21. How does glass behave differently when it is solid versus when it is heated? Why?
22. What crystal forms the basis for much of the microelectronics industry? What makes it so valuable?
23. What physical properties make plastics such a valuable material for manufacturing goods?
24. Describe an example using the terms conduction and thermal equilibrium. Identify each of the following as a thermal conductor or insulator:
a. copper pipe
b. styrofoam cup
c. wooden spoon
d. a vacuum space
e. aluminum pot
Problems
Section 5.1
1. According to the diagram, most of our weather occurs below what altitude?
2. The air in your school can hold 20 g/m3 of water when it is saturated at 70°F. What is the relative humidity of the air in your school at 70°F if the moisture content is 5 g/m3?
3. The diagram to the right shows a graph of temperature vs. time for a material which starts as a
solid. Heat is added at a constant rate. Using the diagram, answer the following questions:
a. During which time interval does the solid melt?
b. During which time intervalis the material all liquid?
c. What is the boiling point of the substance?
d. Does it take more heat energy to melt the solid or boilthe liquid?
Section 5.2
4. Based on the definition of a vacuum, if you were to put an alarm clock inside a vacuum and set it to ring, what would happen when the alarm went off?
5. The diagram shows a cup of cocoa at 65°C. The arrows show the direction of heat conduction as a cold spoon is placed into the cup.
What could the temperature of the spoon be?
a. 75°C
b. 65°C
c. 55°C
6. Which make the best thermal conductor: solids, liquids, or gases? Why?