test 2 Flashcards
1
Q
What does Brownian motion refer to?
A
The random motions of atoms and molecules.
2
Q
Atoms that make up your body were formed in _______.
A
ancient stars.
3
Q
Atoms that make up your body were previously a part of _______.
A
your neighbor’s bodies.
4
Q
Atoms are _______ at all times.
A
in motion.
5
Q
Compared with the wavelength of visible light, atoms are _______.
A
smaller.
6
Q
Which of the following has the smallest mass?
A
electron.
7
Q
What prevents you from falling between the atoms in the floor you stand on?
A
Electrical forces.
8
Q
An element is a substance consisting of _______.
A
atoms of the same kind.
9
Q
The classic periodic table lists the _______.
A
known elements.
10
Q
Investigation of atoms sequenced along each horizontal row (period) of the periodic table shows that atoms decrease in _______.
A
size.
11
Q
If you add or subtract a proton to or from the nucleus of an atom, you produce _______.
A
a completely different atom.
12
Q
The atomic number of an atom is defined in terms of its number of _______.
A
protons.
13
Q
The size of an atom is mostly determined by the space occupied by its _______.
A
electrons.
14
Q
Which element has atoms of the greatest mass?
A
Uranium.
15
Q
Which element has atoms with the greatest number of electrons?
A
Uranium.
16
Q
Molecules are composed of _______.
A
atoms.
17
Q
Atoms combine to form molecules by way of _______.
A
shared or exchanged electrons.
18
Q
A compound is composed of different kinds of atoms in _______.
A
definite proportions.
19
Q
The atoms in isotopes of a particular element have different numbers of _______.
A
neutrons.
20
Q
Isotopes of a given element differ in _______.
A
mass number.
21
Q
The shell model of the atom views electrons as occupying _______.
A
shells.
22
Q
If 1.0 gram of antimatter meets with 4.0 grams of matter, the energy released would correspond to _______.
A
the energy equivalent of.
23
Q
Who is credited for discovering Brownian motion?
A
Robert Brown.
24
Q
Who advanced the idea of atoms in the early 1800s?
A
John Dalton.
25
What causes dust particles and tiny grains of soot to move with Brownian motion?
Collisions with invisible molecules.
26
Who first explained Brownian motion and made a convincing case for the existence of atoms?
Albert Einstein.
27
What did Robert Brown see under the microscope?
Specks of dust moving around.
28
Why did the particles jiggle around?
The particles were struck by atoms unequally on different sides.
29
What happens to a Styrofoam cup placed on a table with a bunch of BBs moving around it?
The cup will move randomly in different directions.
30
Atoms are incredibly tiny, numerous, perpetually moving, and what else?
Ageless.
31
How does the approximate number of atoms in the air in your lungs compare with the number of breaths of air in Earth's atmosphere?
The numbers are about the same.
32
Are most of the atoms around us younger or older than the sun?
Older than the sun.
33
An important feature of atoms is ___ .
that they have wave properties
34
Why can atoms be seen with an electron beam?
The wavelength of the electrons is smaller than an atom.
35
What is the purpose of a model in science?
A model is an abstraction that helps us visualize and predict.
36
Which of the following are negatively charged?
Electrons.
37
The mass of an atom is _______.
concentrated in the atomic nucleus.
38
What is the most abundant element in the known universe?
Hydrogen.
39
Where did the heaviest elements originate?
Nuclear fission in supernovas.
40
What are the five most common elements in humans?
* C
* H
* O
* N
* Ca
41
Which of the following is an element?
Hydrogen.
42
The periodic table of the elements is a list of _______.
atoms.
43
Which of these atoms has the largest number of neutrons in the nucleus?
Gold.
44
How does the helium atom compare to the hydrogen atom?
The helium atom is smaller than the hydrogen atom.
45
What kind of attraction pulls electrons close to the atomic nucleus?
Electric.
46
The pressure increases on a block resting on a table when you increase the _______.
downward force on the block.
47
Water pressure in a lake is _______.
greater at the bottom.
48
Where would a scuba diver feel more pressure, in the ocean or in a deep lake?
In the ocean.
49
If you punch holes in the side of a container filled with water, in what direction does the water initially flow outward from the container?
Perpendicular to the wall.
50
What happens to the force due to pressure on the bottom of an object if you increase its height without changing its depth under water?
The force will increase.
51
What happens to the net buoyant force if you increase the height of the object without changing its depth under water?
The net buoyant force will increase.
52
What happens to the force due to pressure on the bottom of the object if you increase the depth of the object without changing its height?
The force will increase.
53
What happens to the net buoyant force if you increase the depth of the object without changing its height?
The net buoyant force will stay the same.
54
On what factors does the buoyant force acting on an object depend?
* Height of the object
* Density of the fluid
55
A stone of volume V submerged in water displaces the _______.
same volume of water.
56
Why does the buoyant force act upward on an object submerged in water?
The pressure upward on the deeper bottom is greater than the downward pressure on the top.
57
How does the volume of a completely submerged object compare with the volume of water displaced?
The volumes are equal.
58
If a cylinder has twice the radius, how deeply must it be submerged to get the same weight reduction as a smaller cylinder?
Reduce the depth of immersion by a factor of four.
59
When Dr. Hewitt immerses the object in water, how does the loss of weight of the object compare with the buoyant force?
Loss of weight is equal to the buoyant force.
60
What is the buoyant force that acts on a submerged object equal to?
The weight of the fluid displaced by the submerged object.
61
If an object suspended by a scale shows a weight of 3 N in air and 2 N when submerged in water, the buoyant force on the submerged object is _______.
1 N.
62
If an object submerged in water displaces 100 kg of water, the buoyant force on the submerged object is _______.
100 N.
63
How does the buoyant force on a submerged object compare with the weight of the water displaced?
The buoyant force is equal to the weight of the water displaced.
64
An object having the same density as water will _______.
neither sink nor float.
65
A loaded ship arrives at the first freshwater lock of the Panama Canal, will it float higher or lower than in the open ocean?
It will float lower.
66
How is the density of a fish controlled?
A fish changes its volume.
67
The buoyant force on a floating object is _______.
equal to the object's weight.
68
The caissons of the Falkirk Wheel are balanced only when _______.
their water levels are the same.
69
Why do the gondolas of the Falkirk Wheel have the same weight whether or not they carry boats?
The boats displace water out of the gondolas equal to their weights.
70
The operation of a hydraulic press best illustrates _______.
conservation of energy.
71
In a hydraulic lift, if the large piston has twice the area of the small piston, what would the force exerted by the large piston be compared to a force applied on the small piston?
The large piston would have double the force.
72
What happens to the pressure in all parts of a confined fluid if the pressure in one part is increased?
The pressure everywhere increases by the same amount.
73
If the pressure in a hydraulic press is increased by an additional 10 N/cm², how much extra load will the output piston support if its cross-sectional area is 50 cm²?
500 N.
74
As the height of an object increases when completely submerged in water, the net buoyant force _______.
increases.
75
As an object is lowered within the water (away from the surface), the net buoyant force _______.
does not change.
76
The net force due to water pressure, exerted on a flat surface of an object submerged in the water, is equal to _______.
the weight of the fluid displaced by the object.
77
What is required such that an object can float on water?
The weight of the water displaced by the object must be greater than the weight of the object.
78
An object more dense than the fluid in which it is immersed will _______.
sink.
79
An object less dense than the fluid in which it is immersed will _______.
float.
80
An object having a density equal to the density of the fluid in which it is immersed will _______.
neither sink nor float.
81
Atmospheric pressure decreases with increasing _______.
altitude.
82
What keeps the atmosphere around our planet?
Gravity.
83
What happens when Dr. Hewitt places a card on a glass full of colored water and turns it upside down?
The card stays, and the water also stays in the glass.
84
Why do the card and water stay when Dr. Hewitt flips them over?
The card is held up by atmospheric pressure that balances the weight of water.
85
What happens when Dr. Hewitt takes cans containing a small amount of hot water and dips them in cold water?
The cans get crushed.
86
Why do the cans containing a small amount of hot water get crushed when immersed?
The pressure inside them is less than the atmospheric pressure outside.
87
Atmospheric pressure is mainly due to the _______.
weight of the air.
88
Why do climbers need to bring along oxygen when conquering Mount Everest?
To breathe because the atmosphere is less dense than at sea level.
89
What can be said about the pressure of an inflated balloon?
It is equal to the atmospheric pressure.
90
What is the mass of a cubic meter of air at room temperature (20°C)?
1.21 kg.
91
What is the approximate mass of a column of air 1 cm² in area that extends from sea level to the upper atmosphere?
1 kg.
92
How does the weight of mercury in a barometer compare with the weight of an equal cross-section of air from sea level to the top of the atmosphere?
They are equal.
93
Why would a water barometer have to be 13.6 times taller than a mercury barometer?
Mercury is 13.6 times denser than water.
94
A column of mercury 76 cm tall has a weight equal to that of a column of water _______.
10.3 m tall.
95
If the volume of a confined gas is reduced 10 percent, how would the pressure of the gas change?
The pressure would increase by 10 percent.
96
When a party balloon is compressed to one-third its volume, gas pressure in the balloon _______.
triples.
97
Why are high-altitude research balloons only partially inflated when launched?
The atmospheric pressure decreases as they rise.
98
If a divider is placed closer to one side of a tube, how will the speed of the air on the wide and narrow sides compare?
The air will move faster on the narrow side.
99
Which way will air flow through a house if a strong wind blows over the roof and there is an open chimney?
In through the window and out the chimney.
100
A 1 kg balloon at equilibrium in the air is buoyed up with a force of _______.
10 newtons.
101
A helium-filled balloon will reach its maximum altitude when _______.
its weight equals the weight of displaced air.
102
Compared to the water pressure in the large pipes running to your home, what would the internal pressure of the water flowing through the small pipes be?
The pressure in the small pipes would be the lowest.
103
What are streamlines?
Streamlines trace the smooth paths of bits of fluid.
104
Is pressure greater or less in regions where streamlines are crowded?
Less.
105
How does faster-moving air above an airplane wing affect the pressure on the wing?
The pressure decreases.
106
Is the fluid that goes up the inside tube in a hand sprayer pushed up the tube or sucked up? Explain.
It is pushed up the tube by atmospheric pressure into the low-pressure, fast air stream.
107
Which one of these values is the lowest temperature?
270K.
108
The temperature of absolute zero is stated as _______.
-273 C.
109
The temperature scale favored by scientists is _______.
Kelvin.
110
What is meant by 'translational' kinetic energy?
Kinetic energy of motion that carries a molecule from one place to another.
111
Is there a distinction between thermal energy and internal energy? Which term do physicists prefer?
Thermal energy emphasizes heat flow, whereas internal energy is the grand total of all energies inside a substance. Physicists prefer internal energy.
112
When we speak about heat we refer to _______.
energy in transit.
113
Which one of these is the largest amount of energy?
1 Calorie.
114
The amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius is _______.
1 calorie.
115
What is kinetic energy of motion that carries a molecule from one place to another?
Kinetic energy
## Footnote
Kinetic energy is the energy that an object possesses due to its motion.
116
What emphasizes heat flow, thermal energy or internal energy?
Thermal energy
## Footnote
Internal energy is the total energy contained within a system.
117
Which term do physicists prefer: thermal energy or internal energy?
Internal energy
118
When we speak about heat, we refer to ___________.
energy in transit
119
What is the amount of heat needed to raise the temperature of 1 gram of water by 1°C?
1 calorie
120
Heat always flows spontaneously from a warmer to a cooler object ___________.
[true]
121
How is the energy value of foods determined?
The food is burned and the energy released is measured.
122
How many joules (J) are needed to change the temperature of 1 gram of water by 1°C?
4.19 J
123
Compared to that of water, how does the heat capacity of a mystery metal compare if it heats up to 80°C while water heats up to 40°C?
One third as great
124
What happens to an object's atoms as its temperature increases?
The object's atoms gain kinetic and elastic potential energies.
125
What is true about an object that is warmer than room temperature as its temperature decreases?
Thermal energy in the object is transferred to the surrounding air.
126
Rank the water samples of different masses (3.8 kg, 1.2 kg, 1.0 kg) according to the heat released as they cool down.
3.8 kg > 1.2 kg > 1.0 kg
127
What is the specific heat capacity for hot sand compared to plants?
Less than that of plants and vegetation.
128
If a certain material heats up quickly and cools down quickly, it has ___________.
A low specific heat
129
What happens to the length of a strip of iron when its temperature increases?
It also increases.
130
Water is denser at ___________.
4 Celsius
131
Why is Europe generally warmer in the winter compared to Northeastern Canada despite receiving the same amount of sunlight?
The gulf stream carries warm, high heat capacity water past the west coast of Europe.
132
What kind of strip is Dr. Hewitt holding?
A strip consisting of brass on one side and steel on the other, welded together.
133
What happens when Dr. Hewitt heats the strip?
It bends.
134
Why does the strip behave as it does when heated?
Both metals expand unequally.
135
Why are gaps left between different plates when building bridges?
To leave room for heat-related expansion.
136
How does the temperature at the bottom of a deep frozen lake compare to the temperature at the bottom of the ocean near the poles?
They are the same, 4°C.
137
What happens to the volume of air as it rises?
Volume increases; temperature decreases.
138
What happens to the speeds of molecules of air when compressed by a tire pump?
Speeds increase; temperature increases.
139
How does thermal conduction mostly involve the motion of ___________?
Electrons
140
Why are igloos warmer inside despite being made of snow?
Because ice is a good insulator.
141
When air rapidly expands, what happens to its temperature?
It decreases.
142
What process mainly takes the heat from the bottom of a pot of water to the surface?
Convection.
143
What is evaporation?
Evaporation is when the fastest molecules at the surface of a liquid have escape velocity and leave to become a gas.
144
What is the temperature at which the combined effects of contraction and expansion produce the smallest volume for water?
4°C.
145
What happens to the amount of 'microscopic slush' in cold water when its temperature increases?
It decreases.
146
What is condensation?
Condensation is when a gas becomes a liquid. It is a warming process.
147
What is the basic difference between a cloud and fog?
Fog is a cloud near the ground.
148
What happens when you heat ice at -40°C?
The temperature increases until the ice reaches its melting point.
149
What happens when you heat water that is at 0°C?
The temperature increases until it reaches 100°C.
150
Melting and freezing are __________.
Opposite processes.
151
What happens to the hexagonal open structure of ice when sufficient pressure is applied?
The crystals are crushed to form the liquid phase.
152
What is the purpose of a pressure cooker?
To increase the boiling temperature.
153
What happens to water at room temperature if you decrease the atmospheric pressure around it?
It will first boil and then freeze.
154
What is the process where adding pressure causes ice to melt, and then when the pressure is removed, the molecules crystallize and refreeze?
Regelation.
155
What is sublimation?
Sublimation is when the fastest molecules at the surface of a solid have escape velocity and leave to become a gas.
156
What happens to water pressure at the bottom of a geyser when some water gushes out?
The water boils.
157
What evidence can you cite for the claim that water can boil at a temperature of 0°C?
Ice will form in boiling water in a vacuum chamber.
158
How many calories are needed to melt 1 g of ice at 0°C?
80 calories.
159
How many calories are needed to vaporize 1 g of boiling water at 100°C?
540 calories.
