Physical Changes in Matter Quiz

What is the heat of vaporization?

The amount of energy you need to put into one gram of a liquid for it to boil. Or for its molecules to be able to overcome their attractions.

What is the heat of fusion?

The amount of energy you need to put into one gram of a solid for it to melt. Or for the molecules to overcome attractions.

What is the arrangement of molecules like as water melts or freezes?

The arrangement of molecules in water becomes less orderly as water melts and more orderly as it freezes.

What happens to the temperature of a substance during phase change? Why?

The temperature stays the same. That is because the absorbed energy is used to allow the particles to overcome their attractions to other particles.

What is vaporization? What type of process is it and why? What are its two types?

Vaporization is the phase change in a substance changes from a liquid into a gas. It is an endothermic process because a substance must absorb energy to change from a liquid into a gas . Its two types are evaporation and boiling.

How does boiling work?

When heat increases, the average kinetic energy of molecules increases thus causing them to move faster. When they have moves fast enough they are able to overcome the attraction of their neighboring molecules.

How does freezing work?

When water is placed in freezing temperature, the energy flows from the water to the air and the average kinetic energy of the molecules decreases and they begin to move more slowly. When molecules move slowly enough, attractions between the molecules start to take an effect. This is what solidifies the water or any liquid.

How do you calculate percent error?

[(calculated measurement- accepted measurement)/accepted measurement] x 100

What is boiling?

The process which changes substance from a liquid to a gas at its boiling point.

Describe the heating curve for substances.

1.solid 2. solid and liquid(melting) 3. liquid 4.Liquid and gas (boiling) 5. gas

What is chemical change? What are some examples?

A change is a substance that involves a change in identity or chemical makeup of a substance. Examples include: fermentation, oxidation and combustion.

What is an endothermic change? What are the endothermic changes?

A change of state in which a system absorbs energy from its surroundings. The endothermic changes are solid to liquid, liquid to gas and solid to liquid.

What is an exothermic change? What are the exothermic changes?

A change of state in which a system releases energy into its surroundings.The exothermic changes are liquid to solid, gas to to solid and gas to liquid.

What is a phase change?

A phase change is a reversible change that occurs when a substance changes from one state of matter to another

How do Chemical and physical changes overlap?

All chemical changes are accompanied by a physical change though physical change is not always accompanied with chemical change.

How does melting work?

As heat flows to ice (used in this example), the molecules gain energy and vibrate more quickly. when a molecule gains enough energy, it can overcome the attractions that keep them in their fixed position of a solid. When all of them have done this, then the process is complete.

Why is changing the amount of a substance only considered a physical change?

Because only the amount or the state of the substance is changing not is chemical makeup or composition.

Why do densities from different substances change even when they are both pure?

Different atoms have different masses and different substances have different atoms. This causes variation among densities in pure substances.

How does the energy of a system change during a phase change?

Energy is either released during condensing and freezing causing the energy of the system to decline or energy is absorbed during evaporation and melting causing the energy of the system to increases

Where does evaporation and boiling take place?

Evaporation takes place at the surface of a liquid and below its boiling point. Boiling takes place at its boiling point

Name the six common phase changes.

Melting, vaporization, condensation, freezing, sublimation, depostition,

How does evaporation work ?

Molecules at the liquid´s surface gain enough energy and move fast enough for the liquid to become vapor. The greater the surface the easir it is to evaporate.

How does condensation work?

Molecules lose enough energy or cool down enough to initiate attractions bettween neighboring molecules.

What is physical change? What are some examples?

Physical change is when some of the properties of a substance change but the composition of the substance remains the same. Examples include grinding, melting, ducting and folding.

What is deposition? Give example.

The phase change in which a gas or vapor changes into a solid without first changing into a liquid. An example is frost forming on windows. Water vapor coming in contact with the cold glass window the vapor molecules lose enough energy to change directly from gas to solid.

What is condensation?

The phase change in which a substance changes from a gas vapor to a liquid.

What is sublimation? What is an example of it?

The phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid. An example is dry ice.

What is vapor pressure? Hoe does temperature affect it?

The pressure cause by collisions of vapor that collect above the liquid and the walls of a container. When it is hotter, the vapor pressure increases.

What is Evaporation?

The process that changes a substance from a liquid to a gas below the temperature´s boiling point

What is percent error?

an expression of the difference between a measured value and the known or accepted value. It is often used in science to report the difference between experimental values and expected values.