60 Questions from Science Practice Test 4

What is the advantage in making an alloy by mixing the elements as powders and then heating them?

The metals blend at lower temperatures so they may be quickly molded.

If the half-life of a radioactive isotope is 5,730 years, the fraction of the original sample that will be left after 17,190 years is

1/8

A mixture that is made of two or more elements-one that is a metal-that has the properties of a metal is a(n)

alloy

Bronze, brass, sterling silver, and solder are examples of

alloys

Many ______ are made by melting and mixing them together in carefully measured amounts.

alloys

What is an advantage that alloys might have over many pure metals?

alloys resist rust

A(n) _____ particle is positively charged and consists of two protons and neutrons.

alpha

A piece of paper will provide protection from

alpha radiation

A(n) ____ ________ is a fast-moving electron given off by a nucleus during radioactive decay.

beta particle

_____ is an alloy of iron with carbon, nickel, and other elements.

brass

About 5,000 years ago, an alloy of copper and tin was discovered to be stronger and harder than either metal alone. The alloy is called

bronze

_________ is a strong and flexible natural polymer in the walls of plant cells.

cellulose

Hard, crystalline solids made by heating clay and other minerals to high temperatures are

ceramics

_____ resist moisture, do not conduct electricity, and can withstand very high temperatures.

ceramics

Hard, crystalline solids made by heating ________ and other minerals to high temperatures are called ceramics.

clay

A polymer may be combined with one or more substances to make a new material called a(n)

composite

Two or more substances may be combined to produce a new material with different properties. This new material is called a(n)

composite

Ceramics are used as electrical insulators because they do not

conduct electricity

Which of the following is NOT a property of glass? (Bends light, resists heat, carries light messages, conducts electricity)

conducts electricity

The disposal of radioactive wastes is an environmental concern because radiation is

dangerous to living things

The half-life of a radioactive isotope is the length of time needed for half the atoms of a sample to

decay

Measurements of half-life make radioactive isotopes useful for

determining the ages of rocks and fossils

Beta radiation consists of particles that are identical to

electrons

A composite known as __________ is made of strands of glass fiber that are woven together and strengthened with a liquid plastic that sets like glue.

fiberglass

During radioactive decay, atomic nuclei of unstable isotopes

give off nuclear radiation

The reason radioactive isotopes can be followed through the steps of a chemical reaction or industrial process is that they

give off radiation

_____ is made by heating sand to make a thick liquid that is shaped and then cooled.

glass

The time needed for half the atoms of a radioactive isotope to decay is known as the _________ of the isotope

half-life

Synthetic polymers are ___________ to make, strong, and last a longtime

inexpensive

Steel is an alloy of one or more elements combined with

iron

Atoms with the same number of protons and different number of neutrons are called

isotopes

One advantage of recycling synthetic polymers is that

less coal and oil will be used in producing synthetic polymers

Aluminum alloys are used for the outer covering of airplanes because the alloys are strong, resistant to corrosion, and

lightweight

In every alloy, at least one of the components is a(n)

metal

Changing some of the _____ that make up a complex polymer would probably result in a compound with different chemical properties

monomers

Glass has _________ crystal structure

no

Reactions involving the particles in the nucleus of an atom are called

nuclear reactions

A threadlike piece of glass that is used to transmit light messages is called a(n)

optical fiber

What materials are being used to replace copper telephone and cable television lines?

optical fibers

Which of these is an alloy? (Pewter, tin, copper, gold)

pewter

A large, complex molecule built from smaller molecules joined together is a(n)

polymer

Becquerel observed that a photographic plate developed an image of a uranium sample even though the plate was wrapped in paper. He hypothesized that the uranium must be emitting energy in the form of

radiation

Because radioactive isotopes decay at a predictable rate, the half-life can be used to tell how old a material is by the process of

radioactive dating

In 1896, the French scientist Henri Becquerel discovered

radioactive decay

The atomic nuclei of unstable isotopes release fast-moving particles and energy in a process called

radioactive decay

The spontaneous emission of radiation by an unstable atomic nucleus was named _____________ by Marie Curie.

radioactivity

Which of the following properties is NOT characteristic of steel? (Hardness, resistance to corrosion, strength, reacts readily with air)

reacts readily with air

One useful property of ceramics is their ability to

resist moisture

The main ingredient used to make glass is

sand

Wood is a natural composite made of two plant polymers, lignin and cellulose. Without cellulose, a tree branch would probably

snap more easily

Pure gold is not used for jewelry because it is too

soft

By mistake, some ceramic flowerpots are only heated to 200 degrees Celsius. As a result, these flowerpots might (turn to glass, develop unusual electrical properties, be less brittle than flowerpots, soften and break down into clay when wet)

soften and break down into clay when wet

The disposal of radioactive materials must be carefully managed because they

sometimes have long half-lives

What strong alloy, containing carbon, iron, and another metal like chromium or nickel, is used to make construction equipment, bicycle frames, and train rails?

steel

Plastics, nylon, and PVC piping are examples of _________ polymers

synthetic

_________ polymers, such as plastics, do not break down into simpler materials in the environment.

synthetic

A radioactive isotope that can be followed through the steps of a chemical reaction is called a(n)

tracer

Radioactive isotopes called _______ can be used to detect some medical problems

tracers

In radiation therapy,

unhealthy human cells are destroyed

____ is a natural composite made of lone fibers of cellulose held together by another polymer called lignin.

wood