Physical Science - Chapter 2

BJU

1. What has mass and takes up space?

matter

three examples of non-matter.

light, sound, heat

evidences that led to the acceptance of the particle model of matter.

diffusion, fixed, whole number ratios of masses of products to reactants in chemical reactions, law of definite proportions, and Brownian motion

4. Why was the particle model of matter accepted over competing models?

It was more workable. It explained the observations of matter better than other models did. It also made more accurate predictions.

5. Define weight.

Weight is the measure of Earth’s gravity acting on an object.

How do Aristotle’s model of matter and the particle model of matter represent matter?

Both represent some aspects of matter. As far as we can tell, matter can be divided into smaller, identical pieces. But we have come to learn that there is a limit to how small matter can be divided. We can get to the atom but can’t divide it into pieces of identical matter, which is not predicted by Aristotle’s model. Neither model perfectly represents real matter. The particle model is more workable in that it explains more of the observations about matter and makes more accurate predictions.

18\. Considering the formula for density, how will the volume of a piece of lead with a density of 11.34 g/mL change if you double the mass of the sample?

Since the density doesn’t change, the volume would also double.

19\. How can the weight of an object change even when its mass remains constant?

Taking matter to space or another planet can alter the force of gravity causing a change in weight.

Define mixture.

a combination of two or more substances physically combined in a changeable ratio.

What do we call a mixture that appears the same throughout?

homogeneous

Give an example of an element

carbon, iron, Helium, etc.

Give an example of: a compound

water

Give an example of: a heterogeneous mixture

trail mix

Give an example of: a homogeneous mixture

tea

Compare a pure substance with a mixture.

A pure substance is made of only one type of material, whereas a mixture is two or more

A substance with low density and changeable shape and volume that is highly compressible is in what state of matter?

gas, but plasma also.

What term is used to describe the ability of liquids and gases to flow?

fluid

Describe a typical liquid.

Liquid is the state of matter in which the particles are close together but have some freedom of movement. Liquids have medium to high densities and low compressibility. Liquids are fluids and can change their shape, though their volume is fixed.

Relate the spacing of particles in solids, liquids, and gases to their motion according to the particle model.

The particle model states that all matter is made of tiny particles in constant motion. Particles move faster as substances warm up, so they move slowest in a solid, faster in a liquid, and fastest in a gas. The faster the particles move, the more space between them, so solids are most closely spaced, and gases are most widely spaced.

If particles in any substance are in constant motion, why can’t solids flow?

The particles in a solid are held in place by the attractive forces between them. Thus, a solid can’t flow and has a fixed shape.

What causes different liquids to vary in their viscosity?

the variation in attractive forces between particles

Compare physical and chemical changes.

Both are changes to matter. Physical changes modify only the appearance of a substance. Chemical changes alter a substance’s chemical makeup.

A solid’s and liquid’s volume is…

fixed

A gas’s volume is…

changeable

What state of matter has a fixed shape?

solid

What states of matter have changeable shapes?

liquid and gas

Solids and liquid have what type of compressibility?

low

Gas has what type of compressibility?

high

What type of particle spacing does solids and liquids have?

close

What type of density does a solid have?

high

What type of density does a gas have?

low

What type of density does a liquid have?

between that of a solid and gas

What type of particle motion does a solid have?

vibrates in place

What type of particle motion does a liquid have?

slides past each other

What type of particle motion does a gas have?

high speed

Does a solid have fluid?

no

Do liquids and gases have fluid?

yes

What is a physical change?

A physical change is any change to a substance that does not alter its chemical composition.

14\. Define chemical property.

A chemical property describes how a substance changes as it interacts with another substance. (p. 41)

Give the opposite change of state for the following processes.

a. freezing to melting b. condensation to vaporization c. deposition to sublimation

Give an example of deposition.

snow formation, frost forming on a cold surface, soot coating a chimney)

The mass of ash remaining after a log burns is much less than the original mass of the log. If the law of conservation of matter is true, how can you explain this?

Conservation of matter states that matter cannot be created or destroyed. The mass decrease is due to some of the matter escaping in the smoke as gases and particulate matter.

Describe what happens to the particles in a material as it is warmed from a solid to a liquid and ultimately to a gas.

As a solid is warmed, its particles vibrate faster until they have enough energy to overcome the forces holding them rigidly in place. The substance becomes a liquid. As the liquid is heated, the particles move faster until they have enough energy to overcome all the attractive forces between the particles and the substance becomes a gas.

Explain how matter changes state as energy is removed.

As energy flows out of a substance, the particles of the substance move more slowly. As the particles in a gas cool, they have less kinetic energy; when enough energy has been removed, the particles can’t overcome the attractive forces and will stick together in a liquid. Condensation has occurred. As more energy is removed, the process continues until the particles get locked in place and the substance freezes to become a solid.