Science Ch. 6.1-6.7 Quiz
E8) If you add the same amount of heat to two different materials of the same mass, will you produce the same increase in temperature? Why or why not?
No because materials have different specific heat capacities so they will heat up at different rates.
21) Northeastern Canada and much of Europe receive about the same amount of sunlight per unit area. Why is Europe generally warmer in the winter?
The Atlantic current (Gulf Stream) carries warm water northeast from the Caribbean. It holds much of its thermal energy long enough to reach the North Atlantic off the coast of Europe, where it cools.
2) What happens to the temperature of air when it is rapidly compressed?
The air becomes warmer. molecules collide-> friction-> heat
1) Why does a penny become warmer when struck by a hammer?
The hammer's blow causes the penny's atoms to jostle faster.
14) What determines the direction of heat flow?
high to low temperature
18) Which warms up faster when heat is applied-iron or silver?
silver because it takes less time (less than a min vs iron which takes about 2 min)
20) How does the specific heat capacity of water compare with the specific heat capacities of other common materials?
Water has a much higher capacity for storing energy than all but a few uncommon materials.
E6) If you drop a hot rock into a pail of water, the temperature of the rock and the water change until the two are equal. The rock cools and the water warms. Does this hold true if the hot rock is dropped into the Atlantic Ocean? Explain.
Yes; the rock cools and the water warms until it reaches equilibrium, but it only changes by a very small amount.
What is thermal energy?
(internal energy) The total energy (kinetic plus potential) of the particles that make up a substance.
9) Why are there no negative numbers on the Kelvin scale?
0 K = absolute zero
17) Distinguish between a calorie and a joule.
1 calorie = 4.184 joules
6) By how much does the pressure of a gas in a rigid vessel decrease when the temperature is decreased by 1 C*?
1/273
7) What pressure would you expect in a rigid container of 0*C gas if you cooled it by 273*C?
273/273 volumes which would be reduced to zero volume (theoretical)
What is temperature?
A measure of the hotness of an object, related to the average kinetic energy per molecule in the object, measured in degrees Celsius, degrees Fahrenheit, or kelvins.
What is a Calorie?
A unit of thermal energy, or heat. One calorie is the thermal energy required to raise the temperature of 1 gram of water 1 Celsius degree (1 cal = 4.184 J). One Calorie (with a capital C) is equal to 1,000 calories and is the unit used in describing the energy available from food.
13) Distinguish between heat and thermal energy.
Heat is thermal energy in transit. Thermal energy is PE+KE.
12) Distinguish between temperature and heat.
Heat is thermal energy transferred due to a temperature difference. Temperature is a measure of hotness relating to the average KE of an object.
5) What is meant by the statement "a thermometer measures its own temperature"?
It comes in contact with something and energy flows through them until the temperatures reach equilibrium.
25) Which generally expands more for the same increase in temperature-solids or liquids?
Liquids generally expand more than solids for the same increase in temperatures because there is less movement in solids.
What is absolute zero?
The lowest possible temperature; the temperature at which all particles have their minimum kinetic energy.
23) Why is hot water poured into a drinking glass more likely to break the glass if the glass is thick?
The outer layer of the glass expands at a different rate than the inner layer.
E7) Why does the pressure of a gas enclosed in a rigid container increase as the temperature increases?
The pressure increases because the average KE of the molecules increases.
What is specific heat capacity?
The quantity of heat per unit of mass required to raise the temperature of a substance by 1 Celsius degree. Also known as thermal inertia.
24) How is a bimetallic strip used to regulate temperature?
The strip may turn a pointer, regulate a valve or close a switch causing the strip to bend.
What is heat?
The thermal energy that flows from an object at higher temperature to one at a lower temperature, commonly measured in calories or joules.
11) When you touch a cold surface, does "coldness" travel from the surface to your hand or does thermal energy travel from your hand to the cold surface? Explain.
Thermal energy travels from your hand to the cold surface because the direction of thermal energy flow is always high to low temperatures.
15) How is the energy value of foods determined?
by burning and measuring energy released (calories).
16) Distinguish between a calorie and a Calorie.
calorie = amount of heat required to change the temperature of 1 g of water by 1*C. Calorie = amount of heat required to change the temperature of 1 kg of water by 1*C. Calorie = 1,000 calories
3) What are the temperatures for freezing and boiling water on the Celsius and Fahrenheit scales?
freezing: 0*C , 32*F boiling: 100*C , 212*F (fyi: altitude makes a difference)
19) Does a substance that heats up quickly have a high or a low specific heat capacity?
low specific heat capacity
8) What is the temperature of melting ice on the Kelvin scale? Of boiling water at atmospheric pressure?
melting ice: 273 K boiling water: 373 K (fyi: add 273 to Celsius)
22) Because of the law of energy conservation, something must warm up if ocean water cools. What is that something?
the air
4) What is the temperature of an object a measure of?
the average kinetic energy per molecule in an object
10) When is thermal energy in a substance evident?
when there are changes in temperature