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