1.
Fluids include___________.
Correct Answer
B. Liquids,gases and plasmas
Explanation
Fluids include liquids, gases, and plasmas. Liquids are substances that have a definite volume but no definite shape, while gases are substances that have neither a definite shape nor volume. Plasmas, on the other hand, are ionized gases with highly conductive properties. Therefore, the correct answer is that fluids include liquids, gases, and plasmas.
2.
1 Pa=________
Correct Answer
A. N/m2
Explanation
The correct answer is N/m2. This is because Pa stands for Pascal, which is the SI unit of pressure. N/m2 represents Newton per square meter, which is the unit used to measure pressure. It indicates the amount of force exerted per unit area.
3.
Gas exert pressure due to the
Correct Answer
B. Force exerted by the collision of gas molecules
Explanation
Gas exerts pressure due to the force exerted by the collision of gas molecules. When gas molecules collide with each other or with the walls of their container, they exert a force. This force is responsible for the pressure exerted by the gas. The more frequent and energetic the collisions, the higher the pressure. Therefore, the force exerted by the collision of gas molecules is the correct explanation for gas exerting pressure.
4.
According to Charles law at -273ËšC(absolute zero) the gas would have__________
Correct Answer
B. Zero volume
Explanation
According to Charles' Law, which states that the volume of a gas is directly proportional to its temperature, as the temperature decreases, the volume of the gas also decreases. At absolute zero (-273ËšC), the gas molecules would have the least amount of kinetic energy, resulting in minimal movement and a consequent reduction in volume. Therefore, the correct answer is "zero volume."
5.
Pressure exerted by the force of 10N on an area of 1cm2is_____
Correct Answer
A. 1.0X105N/m2
Explanation
The pressure exerted by a force on an area is calculated by dividing the force by the area. In this case, the force is 10N and the area is 1cm2. Converting the area to m2 by dividing by 10000, we get 0.0001m2. Dividing the force by the area gives us 10N/0.0001m2 = 100,000N/m2. Therefore, the correct answer is 1.0X105N/m2.
6.
Compare:pressure exerted while standing on two foot and while standing on one foot.When you stand on one foot you exert______________
Correct Answer
B. More pressure
Explanation
When standing on one foot, the pressure exerted is more compared to standing on two feet. This is because the weight of the body is concentrated on a smaller surface area when standing on one foot, resulting in a higher pressure being applied. In contrast, when standing on two feet, the weight is distributed over a larger surface area, reducing the pressure exerted.
7.
Why does ear pops when you are flying high on an airplane
Correct Answer
A. For balancing the changing pressure
Explanation
When flying high on an airplane, the air pressure outside the ear decreases while the pressure inside remains the same. This creates an imbalance, causing the ear to "pop" as it tries to equalize the pressure. The popping sensation occurs when the Eustachian tube, which connects the middle ear to the back of the throat, opens briefly to allow air to enter or exit the middle ear, thus balancing the changing pressure.
8.
Warm air is____________and colder air is____________
Correct Answer
B. Less dense,denser
Explanation
Warm air is less dense compared to colder air because the molecules in warm air are more spread out and have higher kinetic energy, causing them to move faster and occupy more space. On the other hand, colder air is denser because the molecules are closer together and have lower kinetic energy, resulting in a smaller volume and higher density.
9.
According to Boyle's law at constant temperature when the volume is reduced,the pressure would increase.Why this happens?
Correct Answer
A. More collision and more pressure
Explanation
When the volume of a gas is reduced at constant temperature, the gas particles are confined to a smaller space. This means that there is less space for the gas particles to move around, leading to an increase in the frequency of collisions between the particles and the walls of the container. As a result, the pressure exerted by the gas on the walls of the container increases. Therefore, the statement "more collision and more pressure" is the correct explanation for why the pressure increases when the volume is reduced at constant temperature according to Boyle's law.
10.
Jacques Charles cooled a gas and found that volume and temperature are
Correct Answer
B. Linear
Explanation
Jacques Charles cooled a gas and found that volume and temperature are linearly related. This means that as the gas is cooled, the volume decreases proportionally to the decrease in temperature. The relationship between volume and temperature is represented by a straight line on a graph, indicating a constant rate of change. This discovery led to the formulation of Charles's Law, which states that the volume of a gas is directly proportional to its temperature at constant pressure.
11.
Real gases occupies space and exerts attractive forces,where as ideal gas is assumed to occupy no space and they don't exert any attractive forces.(kinetic theory of gases-261)
Correct Answer
A. True
Explanation
Real gases are composed of actual molecules that have volume and interact with each other through attractive forces. These interactions cause the gas molecules to occupy space and deviate from ideal gas behavior. On the other hand, ideal gases are hypothetical gases that are assumed to have no volume and do not exert any attractive forces. This assumption allows for simplified calculations and modeling of gases under certain conditions. Therefore, the statement that real gases occupy space and exert attractive forces while ideal gases do not is true.
12.
What happens when water is heated from
0Ëš C to 4Ëš C.
Correct Answer
A. Contracts and volume decreases
Explanation
When water is heated from 0Ëš C to 4Ëš C, it undergoes a unique change in volume. Unlike most substances, water contracts instead of expanding as it is heated within this temperature range. This contraction causes the volume of water to decrease. This phenomenon occurs due to the unique structure of water molecules, which form a lattice-like arrangement at lower temperatures. As the temperature increases, the molecules gain more energy and move more freely, causing the lattice structure to break and the water to contract.
13.
The water is most dense at ________________and makes ice to float.
Correct Answer
B. 4Ëš C
Explanation
Water is most dense at 4Ëš C. As water cools below this temperature, the hydrogen bonds between water molecules start to form a lattice-like structure, causing the water molecules to move further apart and the density to decrease. This expansion of water molecules when freezing is unusual and causes ice to be less dense than liquid water, which is why ice floats in water.
14.
Plasma is made of____________
Correct Answer
A. Negatively charged electrons and positive ions
Explanation
Plasma is a state of matter in which atoms are ionized, meaning they lose or gain electrons. This results in the presence of both negatively charged electrons and positively charged ions. Therefore, the correct answer is "negatively charged electrons and positive ions."
15.
Sun's plasma is______________
Correct Answer
A. Denser than most solids on Earth
Explanation
The correct answer is "denser than most solids on Earth." This means that the plasma found in the Sun is more tightly packed and has a higher mass per unit volume compared to most solid substances found on Earth. This is due to the extremely high temperatures and pressures present in the Sun, which cause the atoms and molecules in the plasma to be highly energetic and closely packed together.
16.
The only difference between gas and plasma is _______________
Correct Answer
C. Plasma conducts electricity
Explanation
Plasma is a state of matter that is similar to gas but with one key distinction - it can conduct electricity. Unlike gas, which does not have the ability to conduct electricity, plasma is made up of charged particles that can carry an electric current. This characteristic of plasma makes it useful in various applications, such as in plasma TVs and fluorescent lights.
17.
Gas and plasma both has
Correct Answer
A. No volume ,no shape
Explanation
Gas and plasma both have no volume and no shape because they are both states of matter that do not have a fixed shape or volume. In the gas state, the particles are spread out and move freely, occupying the entire space available to them. Similarly, in the plasma state, the particles are highly energized and ionized, and they also do not have a definite shape or volume. Therefore, the statement "no volume, no shape" accurately describes both gas and plasma.
18.
Pressure is a ____quantity
Correct Answer
B. Scalar
Explanation
Pressure is a scalar quantity because it only has magnitude and no direction. Scalar quantities are described by a single value or number, such as temperature or mass, and they do not have any associated direction. In the case of pressure, it is defined as the force per unit area and is measured in units like pascals (Pa) or atmospheres (atm). The magnitude of pressure can vary, but it does not have a specific direction associated with it. Therefore, pressure is classified as a scalar quantity.
19.
1 mole = _____________particles
Correct Answer
C. 6.022X1023
Explanation
The answer is 6.022X10^23 particles because Avogadro's number is defined as the number of particles (atoms, molecules, ions, etc.) in one mole of a substance. This number is approximately 6.022X10^23, so one mole is equal to 6.022X10^23 particles.
20.
Ideal gas law predicts the behavior of gases except under conditions of ________(page264)
Correct Answer
A. High pressure or low temperatures
Explanation
The ideal gas law, which relates the pressure, volume, temperature, and number of moles of a gas, is applicable to most gases under normal conditions. However, at high pressures or low temperatures, the behavior of gases deviates from what is predicted by the ideal gas law. At high pressures, the volume occupied by the gas molecules becomes significant, and intermolecular forces start to play a role. At low temperatures, the kinetic energy of the gas molecules decreases, leading to a decrease in their average speed and a greater influence of intermolecular forces. Therefore, under these conditions, the ideal gas law is not accurate in predicting the behavior of gases.
21.
Increasing number of gas particles in a closed container results in_______________
Correct Answer
A. High pressure
Explanation
When the number of gas particles in a closed container increases, the frequency of collisions between the particles and the container walls also increases. This leads to an increase in the total force exerted by the gas on the container walls, resulting in an increase in pressure. Therefore, the correct answer is high pressure.
22.
Two boxes with a size of 20cmX20cmX20cm and 20cmX20cmX40cm suspended by thin strings in mid air.Compare the pressure of air on the outside of two boxes.
Correct Answer
B. Pressure of the air is same
Explanation
The pressure of the air on the outside of the two boxes is the same because pressure is determined by the force exerted by the air molecules on a given area. The size or shape of the boxes does not affect the pressure, as long as the area being considered is the same. In this case, since we are comparing the pressure on the outside of both boxes, the area being considered is the same (the surface area of each box). Therefore, the pressure of the air on the outside of both boxes is the same.
23.
Nitrogen gas at standard atm.pressure 101.3kPa has a volume of 0.080m3.If there are 3.6mol of gas,what is the temperature?
Correct Answer
C. 270K
Explanation
The temperature of a gas can be determined using the ideal gas law equation, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature. In this question, we are given the pressure (101.3 kPa), volume (0.080 m3), and number of moles (3.6 mol) of nitrogen gas. We can rearrange the ideal gas law equation to solve for temperature: T = PV / (nR). Plugging in the given values, we get T = (101.3 kPa * 0.080 m3) / (3.6 mol * 8.314 J/(mol*K)). Simplifying this equation gives T = 270 K. Therefore, the correct answer is 270K.
24.
Gas with a volume of 10.0L is trapped in an expandable cylinder.If the pressure is tripled and the temperature is increased by 80%(kelvin scale).What will be the volume of gas?
Correct Answer
C. 6.00L
Explanation
When the pressure of a gas is tripled, its volume decreases by a factor of 1/3 according to Boyle's Law. However, when the temperature is increased by 80% (or 0.8 in decimal form), the volume increases by a factor of 1 + 0.8 = 1.8 according to Charles's Law. Therefore, the final volume can be calculated by multiplying the initial volume by the two factors: 10.0L * (1/3) * 1.8 = 6.00L.
25.
Thermal expansion ______________
Correct Answer
B. Decreases the density of matter
Explanation
When an object is heated, its particles gain energy and move faster, causing the object to expand. This expansion leads to an increase in volume while the mass remains constant, resulting in a decrease in density. Therefore, thermal expansion decreases the density of matter.