The two main branches of science are

physics and chemistry.

natural and physical science.

natural and social science.

biological and earth science.

Which of the following is not a branch of biology?

• geology

• zoology

• ecology

• medicine

Technology can best be defined as

• science that uses computers.

• applied science.

• new inventions.

• the use of lenses and microscopes.

For a scientific theory to be valid, it must allow you to

• perform experiments.

• obtain new results each time.

• find a new, more complex explanation.

• make predictions.

Each molecule of hydrochloric acid, HCl, contains one atom of hydrogen

and

• one atom of chlorine.

• one atom of oxygen.

• two atoms of chlorine.

• two atoms of oxygen.

Solid ionic compounds have very high melting points because they

• are positively charged.

• contain metallic elements.

• are made of elements that are solid at room temperature.

• contain charged ions that are locked tightly together.

In which type of bond do atoms share pairs of electrons?

• covalent bonds

• metallic bonds

• ionic bonds

• polyatomic bonds

The first step in the scientific method is usually

• making an observation.

• forming a hypothesis.

• collecting data.

• testing a hypothesis.

The sample contained the same number of pennies for which two years?

• 1988 and 1992

• 1988 and 1991

• 1994 and 1997

• 1994 and 1998

What is 78,900,000,000 expressed in scientific notation?

• 789 x 109

• 7.89 x 109

• 78.9 x 109

• 7890 x 109

A measurement that is accurate is one that

• is as exact as possible.

• is close to the true value.

• contains at least four significant figures.

• contains five decimal places.

A precise measurement is one that

• contains the correct number of significant figures.

• contains at least three significant figures.

• is close to the true value.

• is as exact as possible.

The chemical formula for water, H2O, means that each water molecule

contains

• two hydrogen atoms and two oxygen atoms.

• two hydrogen atoms and one oxygen atom.

• two hydrogen atoms and zero oxygen atoms.

• one hydrogen atom and two oxygen atoms.

The kinetic theory states that the higher the temperature, the faster the

• particles that make up a substance move.

• bonds between atoms break down.

• molecules of gas rush together.

• lighter particles within a substance clump together.

You burn a log of wood, and only a small pile of ashes is left. What has happened?

• A large amount of mass has been lost.• A small amount of mass has been

converted into a large amount of heat energy.

• The total mass of the wood and oxygen is the same as the total mass of the ash and gases.

• The total amount of energy is less than before.

When water is broken down, what happens to the oxygen and hydrogen atoms it is made of?

• They combine with oxygen in air to produce new substances.

• They are rearranged to form hydrogen and oxygen gas

• They are destroyed.

• They increase in size until they form a solid.

Dalton's atomic theory was accepted because

• there was evidence to support it.

• Democritus said that it was correct.

• Dalton invented the electron microscope.

• Dalton showed how molecules are formed.

Which statement about the atomic nucleus is correct?

• The nucleus is made of protons and neutrons and has a negative charge.

• The nucleus is made of protons and neutrons and has a positive charge.

• The nucleus is made of electrons and has a positive charge.

• The nucleus is made of electrons and has a negative charge.

Atoms have no electric charge because they

• have an equal number of charged and noncharged particles.

• have neutrons in their nuclei.

• have an equal number of electrons and protons.

• have an equal number of neutrons and protons.

Which statement about an element's average atomic mass is correct?

• It is determined by counting the number of isotopes in a sample of the element.

• It is equal to one-twelfth the mass of the most common isotope.

• It is a weighted average, so common isotopes have a greater effect than uncommon ones.

• It is based on an isotope's charge, so negatively charged isotopes have a greater effect than positive ones.

An atomic mass unit is equal to

• one-half the mass of a hydrogen atom.

• one-fourth the mass of a lithium atom.

• one-twelfth the mass of a carbon-12 atom.

• one-fifteenth the mass of a nitrogen-15 atom.

Bonus-5 points

Which statement about the alkali metals is correct?

• They are located in the left-most column of the periodic table.

• They are extremely nonreactive.

• They are usually gases.

• They form negative ions with a 1– charge.

Alkali metals are extremely reactive because they

• have very small atomic masses.

• are not solids at room temperature.

• have one valence electron that is easily removed to form a positive ion.

• have two valence electrons that form compounds with calcium and magnesium.

Which statement about noble gases is correct?

• They form compounds with very bright colors.

• They exist as single atoms rather than as molecules.

• They are highly reactive with both metals and nonmetals.

• They are extremely rare in nature.

Semiconductors are elements that

• have large atomic masses but small atomic numbers.

• do not form compounds.

• can conduct heat and electricity under certain conditions.

• are extremely hard.

Most halogens form compounds by

• gaining an electron to form a negative ion.

• losing an electron to form a positive ion.

• losing protons.

• joining with both calcium and carbon.

Transition metals such as copper or tungsten form compounds by

• gaining electrons to form negative ions.

• losing electrons to form positive ions.

• losing neutrons.

• changing shape and color at various temperatures.

Molar mass is defined as

• the number of particles in 1 mole of a substance.

• the SI base unit that describes the amount of a substance.

• the amount of a substance necessary to have a positive charge.

• the mass in grams of 1 mole of a substance.

Bonus-5points

A compound differs from a mixture because it

• always remains frozen even at high temperatures.

• is formed from two cations.

• always contains the same elements in the same proportion.

• can form only in the presence of heat energy.

Gases take up a lot of space because

• they have weak chemical bonds.

• their molecules have very little attraction for one another.

• they contain very few atoms.

• they have a small molar mass.

Often atoms join so that each atom will have

• an even number of electrons.

• an outermost energy level that is full of electrons.

• an equal number of protons and electrons.

• more electrons than either protons or neutrons.

An ionic bond is a bond that forms between

• ions with opposite charges.

• atoms with neutral charges.

• one atom's nucleus and another atom's electrons.

• the electrons of two different atoms.

Copper is a good conductor of electricity because its electrons

• are positively charged.

• are free to move from atom to atom.

• can take on either positive or negative charges.

• are shared between neighboring compounds.

Solid ionic compounds have very high melting points because they

• are positively charged.

• contain metallic elements.

• are made of elements that are solid at room temperature.

• contain charged ions that are locked tightly together.

The name dinitrogen tetroxide tells you that this compound contains

• two nitrogen atoms and two oxygen atoms.

• four nitrogen atoms and two oxygen atoms.

• two nitrogen atoms and four oxygen atoms.

• four nitrogen atoms and four oxygen atoms.

Putting lemon juice on a piece of cut apple will

• make the fruit softer and easier to chew.

• prevent the fruit from turning brown.

• make the fruit taste sweeter.

• neutralize the acid in the fruit.

Acids are substances that

• form hydronium ions when dissolved in water.

• turn red litmus paper blue.

• make foods taste bitter.

• react with neutral liquids to form bases.

An unsaturated solution is one that

• can dissolve more solute at the current conditions.

• will precipitate out all its dissolved solute.

• can dissolve more solute only if heated.

• can dissolve more solute only if the pressure is increased.

Water is referred to as the universal solvent because

• it is found throughout the universe.

• all known substances dissolve in water.

• many different substances dissolve in water.

• it covers more than half of the Earth's surface.

All of the following will make it easier to dissolve a solute in a solvent except

• heating the solvent.

• stirring the solution.

• increasing the surface area of the solute.

• adding a larger amount of solute.

Sugar will dissolve more quickly in iced tea if you stir it because stirring

• absorbs kinetic energy.

• allows dissolved molecules to diffuse through the tea.

• increases the solubility of the solution.

• changes the electric charges of the water molecules.

Solubility refers to the

• size of the particles that make up a substance.

• grams of solute per 100 g of solvent.

• number of moles of solvent dissolved per liter of solution.

• concentration of a solute that is actually dissolved in a solvent.

Distillation can be used to separate solutions of miscible liquids because

• different liquids usually have different boiling points.

• boiling breaks the chemical bonds within each liquid.

• denser liquids sink to the bottom.

• solids remain after the liquids are boiled away.

You can skim the fat off the top of a kettle of cold soup because fat is

• made of small particles.

• less dense than water and rises to the top.

• an emulsion that remains dispersed throughout the soup.

• made of large particles that will not pass through a filter.

You can usually filter out solid particles in a suspension by

• pouring the less dense liquid off the top.

• boiling it so that the solids are left behind.

• distilling the entire suspension.

• using a paper filter to catch the particles.

At which time of day was the temperature approximately 4ºC?

• 9:00 A.M.• 10:00 A.M.• 11:00 A.M.• 12:00 P.M.

The element that is most abundant in Earth is

• iron.

• oxygen.

• silicon.

• magnesium.

A lithium ion is much less reactive than a lithium atom because it

• is much more massive.

• has a full outermost energy level.

• has a negative electric charge.

• is in a different group in the periodic table.