The two main branches of science are physics and chemistry. natural and physical science. natural...

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.