Which equation correctly defines the density of a material?
density = mass / volume
density = volume / mass
density = mass x volume
density = mass + volume
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WhyDensity is mass per unit volume, so density = mass / volume.
2Multiple choice · Easy
In which state of matter are the particles arranged in a regular, fixed pattern and held in place, only vibrating?
Solid
Liquid
Gas
Plasma
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WhyIn a solid the particles are packed closely in a regular arrangement and can only vibrate about fixed positions.
3Multiple choice · Easy
What is the SI unit used for density?
kg/m^3
kg/m^2
m^3/kg
N/kg
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WhyDensity is mass (kg) divided by volume (m^3), giving units of kg/m^3.
4Multiple choice · Easy
Which change of state occurs when a liquid turns into a solid?
Freezing
Melting
Evaporating
Condensing
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WhyWhen a liquid cools and turns into a solid the change is called freezing (solidifying).
5Fill in the blank · Easy
A change of state, such as melting or boiling, is a change because no new substance is made and the change can be reversed.
Answer:
physical
WhyChanges of state are physical (not chemical) changes; the mass is conserved and the process can be reversed by reversing the energy transfer.
6Fill in the blank · Easy
The total kinetic energy and potential energy of all the particles that make up a system is called its energy.
Answer:
internal
WhyInternal energy is the total of the kinetic energy (from particle motion) and potential energy (from particle positions and interactions) of all the particles in a system.
7Multiple choice · Medium
A block of metal has a mass of 600 g and a volume of 75 cm^3. What is its density?
8 g/cm^3
0.125 g/cm^3
45 g/cm^3
675 g/cm^3
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Whydensity = mass / volume = 600 g / 75 cm^3 = 8 g/cm^3.
8Multiple choice · Medium
Which statement best explains why gases are much easier to compress than solids?
Gas particles are far apart with large spaces between them
Gas particles are arranged in a fixed regular pattern
Gas particles are larger than solid particles
Gas particles have no kinetic energy
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WhyIn a gas the particles are far apart with large spaces between them, so they can be pushed closer together; in a solid the particles are already touching.
9Multiple choice · Medium
When a substance is melting, energy is supplied but its temperature does not change. Where does this energy go?
Into breaking the bonds between particles, increasing potential energy
Into increasing the kinetic energy of the particles
It is lost to the surroundings as sound
Into increasing the mass of the substance
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WhyDuring a change of state the energy is used to break the bonds between particles (increasing potential energy), not to raise the temperature.
10Multiple choice · Medium
How much energy is needed to raise the temperature of 2 kg of water by 10 degrees C? (specific heat capacity of water = 4200 J/kg degrees C)
84000 J
8400 J
42000 J
420000 J
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WhyE = m c deltaT = 2 x 4200 x 10 = 84000 J.
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