1.
1. Which group below are all liquids?
Correct Answer
C. Alcohol, water and milk
Explanation
The group "alcohol, water and milk" consists of liquids because all three substances are in a liquid state at room temperature. Water is a well-known liquid, while alcohol (such as ethanol) and milk are also liquids. Salt and sugar are solid substances, and flour is a powder, so they do not belong to the group of liquids. Sea water is a mixture of water and salt, so it contains both a liquid and a solid component.
2.
2. Substance which take the shape of their container, and take up a fixed amount of space are known as:
Correct Answer
B. Liquids
Explanation
Liquids are substances that take the shape of their container and have a fixed volume. Unlike solids, liquids do not have a definite shape and can flow and move freely. They can also be poured and have the ability to fill the shape of any container they are placed in. Gases, on the other hand, do not have a fixed volume and can expand or contract to fill any container. Fluids, in general, refer to substances that can flow, including both liquids and gases.
3.
As the temperature of a substance increases, its particles
Correct Answer
A. Move faster
Explanation
As the temperature of a substance increases, its particles gain more energy. This increased energy causes the particles to move faster and have more kinetic energy. Therefore, the correct answer is that the particles move faster.
4.
A steel ball just fits through a steel ring at room temperature.The ball is then heated and now no longer fits through the ring. Choose which sentence below explains this using the particle model.
Correct Answer
A. The particles in the ball start to move faster and the ball expands
Explanation
As the ball is heated, the particles in the ball gain kinetic energy and start to move faster. This increase in movement causes the particles to spread out and the ball expands in size.
5.
Clouds are formed when:
Correct Answer
C. Water vapour condenses
Explanation
Clouds are formed when water vapor in the air cools and condenses into tiny water droplets or ice crystals. This process happens when warm air rises and cools, causing the water vapor to lose energy and form visible clouds. Therefore, the correct answer is "water vapor condenses."
6.
Diffusion occurs when:
Correct Answer
C. A gas moves around, taking up the space in its container
Explanation
Diffusion occurs when a gas moves around, taking up the space in its container. Diffusion is the process by which particles move from an area of higher concentration to an area of lower concentration. In the case of a gas, the particles move freely and randomly, spreading out and filling the available space in the container. This is why we can smell a perfume or a gas leak even if we are not directly next to the source - the gas particles diffuse through the air, spreading out and reaching our noses.
7.
When an object expands, its volume will-
Correct Answer
A. Increase
Explanation
When an object expands, it means that its particles move apart from each other, causing an increase in the space occupied by the object. As a result, the volume of the object increases. This is because the expansion leads to a larger arrangement of particles, spreading them out and taking up more space than before. Therefore, the correct answer is "increase."
8.
Which of the following is correct?
Correct Answer
C. Solids, liquids and gases contracted when cooled
Explanation
Solids, liquids, and gases contract when cooled because the molecules in these substances slow down and come closer together, resulting in a decrease in volume. This is due to the decrease in kinetic energy of the molecules, which causes them to have less movement and occupy less space. Therefore, all three states of matter experience contraction when cooled.
9.
The transfer of heat by passing of vibrations from particle to particle in a substance is called:
Correct Answer
C. Conduction
Explanation
Conduction is the transfer of heat energy through direct contact between particles in a substance. When particles vibrate, they pass their kinetic energy to neighboring particles, causing them to vibrate as well. This transfer of heat continues throughout the substance until thermal equilibrium is reached. Unlike convection, which involves the movement of a fluid, or radiation, which involves the transfer of heat through electromagnetic waves, conduction relies on direct contact between particles for heat transfer. Therefore, conduction is the correct answer for the given question.
10.
What are the units of measurement for the volume of liquids:
Correct Answer
D. ML
Explanation
The units of measurement for the volume of liquids are mL, which stands for milliliters. Milliliters are commonly used to measure the volume of small amounts of liquid.
11.
The densities of
solids, liquids and gases relate to-
Correct Answer
C. How closely the particles are packed into a unit volume, as well as the mass of the particles
Explanation
The correct answer is "how closely the particles are packed into a unit volume, as well as the mass of the particles." This is because the density of a substance is determined by both the mass of the particles and how closely they are packed together. The more mass a substance has in a given volume, or the more closely the particles are packed together, the higher the density will be. Therefore, both factors contribute to the density of solids, liquids, and gases.
12.
Which state of matter can be easily compressed?
Correct Answer
C. Gases
Explanation
Gases can be easily compressed because the particles in a gas are spread out and have a lot of empty space between them. This allows for the gas to be compressed and the particles to be pushed closer together. In contrast, solids and liquids have particles that are closely packed together, making them difficult to compress.
13.
If a black and a white car are left in the sun, which one would be hotter and why?
Correct Answer
B. Black, absorption of heat
Explanation
The black car would be hotter because black objects absorb more heat from the sun compared to white objects. This is because black objects absorb all wavelengths of light, while white objects reflect most of the light. Therefore, the black car would absorb more heat energy from the sun, causing it to become hotter than the white car.
14.
Water boils at which
temperature:
Correct Answer
B. 100°C
Explanation
Water boils at 100°C because this is the temperature at which the vapor pressure of water equals the atmospheric pressure. At this temperature, the water molecules have enough energy to overcome the intermolecular forces and transition from the liquid phase to the gaseous phase. It is a well-known fact that water boils at 100°C under normal atmospheric conditions.
15.
When a substance
changes from a solid to a liquid, the change of state is called:
Correct Answer
A. Melting
Explanation
When a substance changes from a solid to a liquid, it is called melting. This process occurs when heat is applied to the solid, causing the particles to gain energy and move more freely, eventually breaking the bonds that hold them in a fixed position. As a result, the solid transforms into a liquid state. This change of state is commonly observed in substances such as ice melting into water when heated.
16.
When a substance
changes from a liquid to a gas, the change of state is called:
Correct Answer
B. Evaporation
Explanation
Evaporation is the correct answer because it refers to the process in which a substance changes from a liquid state to a gas state. During evaporation, the molecules of the liquid gain enough energy to break free from their bonds and escape into the surrounding environment as vapor. This process commonly occurs at the surface of the liquid and is influenced by factors such as temperature, surface area, and the presence of air currents.
17.
Dry
Ice is an example of sublimation. It changes state from:
Correct Answer
C. Solid to a gas
Explanation
Dry ice is a solid form of carbon dioxide that undergoes sublimation, which is the direct transition from a solid state to a gas state without passing through the liquid state. Therefore, the correct answer is "solid to a gas".
18.
What three things can happen to radiation heat when it reaches an object?
Correct Answer
A. Transmitted, absorbed, reflected
Explanation
Radiation heat can undergo three processes when it reaches an object: transmission, absorption, and reflection. Transmission refers to the heat passing through the object without being absorbed or reflected. Absorption occurs when the object absorbs the heat energy. Reflection happens when the heat is bounced off the object's surface. These three processes are the possible outcomes when radiation heat interacts with an object.
19.
A clinical thermometer is used to take human temperature. The liquid used in clinical thermometers to measure temperature is
Correct Answer
B. Mercury
Explanation
A clinical thermometer is used to measure human body temperature. Mercury is used as the liquid in clinical thermometers because it is a good conductor of heat and has a high boiling point. It expands and contracts uniformly with temperature changes, allowing for accurate temperature readings. Additionally, mercury is non-toxic and does not evaporate easily, making it safe for use in medical devices.
20.
Which group below has only properties of a solid?
Correct Answer(s)
A. Fixed shape, can be compressed, particles spread out
C. Fixed shape, can't be compressed, particles tightly together
21.
A convection current is caused as warm particles move up and cooler particles move down. A convection current can occur in -
Correct Answer
D. Liquids and gases
Explanation
Convection currents occur when warm particles rise and cool particles sink, creating a circular flow. This phenomenon can happen in both liquids and gases. In liquids, such as water, convection currents can be observed when heat is applied to the bottom, causing the warm water to rise and the cooler water to sink. Similarly, in gases, such as air, convection currents can be seen when a heat source warms the air, causing it to rise and cooler air to descend. Therefore, the correct answer is "liquids and gases".
22.
Air is a mixture of gases. The gas that has the highest percentage component in the atmosphere is:
Correct Answer
A. Nitrogen
Explanation
Nitrogen is the correct answer because it makes up about 78% of the Earth's atmosphere, making it the most abundant gas. Oxygen is the second most abundant gas, accounting for approximately 21% of the atmosphere. Carbon dioxide and water vapor are present in much smaller quantities.
23.
Which of the following is NOT a change of state?
Correct Answer
A. Precipitation
Explanation
Precipitation is not a change of state because it refers to the process of water falling from the atmosphere to the Earth's surface in the form of rain, snow, sleet, or hail. It does not involve a change in the physical state of water. On the other hand, the other options involve changes of state. Water puddles disappearing on a hot day is an example of evaporation, ice disappearing into a drink is an example of melting, and mist forming on a mirror when you have a shower is an example of condensation.
24.
An insulator:
Correct Answer
B. Is a poor conductor of heat
Explanation
An insulator is a material that does not allow the flow of heat easily. It has low thermal conductivity, which means it is a poor conductor of heat. Insulators are used to prevent the transfer of heat between objects or to reduce heat loss. They have high resistance to the flow of heat and are commonly used in insulation materials for buildings, electrical wires, and clothing. Insulators work by trapping air or creating barriers that hinder the transfer of heat energy.
25.
When water is being heated by a Bunsen Burner, it begins to boil. Why does the temperature of the water not change even though more energy is being added by the Bunsen?
Correct Answer
B. Energy is used to break bonds between particles
Explanation
When water is being heated by a Bunsen Burner, the energy being added is used to break the bonds between the water particles rather than increasing the temperature. Breaking these bonds requires energy, and this energy is absorbed by the water molecules, causing them to separate and form gas bubbles, resulting in boiling. Therefore, even though more energy is being added, the temperature of the water does not change because the energy is being used for breaking the bonds between particles rather than increasing the kinetic energy and temperature of the water.