Advertisement Upgrade to remove ads

The nature of science implies that

New scientific findings may cause a change in current thinking in society

The scientific method cannot address which of the following about toxic wastes

science cannot say that a river should not be polluted

Darwin was a self-taught naturalist who gained much field experience during his five-year voyage on the HMS Beagle. Darwin's success as a naturalist can be attributed to:

his ability to ask questions about his observations and to seek unifying principles to answer these questions

Bohr proposed that atoms of any kind contain ____________ particles. Those located in the nuclear core are called neutrons and protons.

subatomic

The number of protons in a given atom is equal to its _______ number.

atomic

Isotopes that decay with a nuclear break-up and emit a significant amount of energy are said to be ______.

radioactive

There are 92 naturally occuring _________, each made up of atoms which contain a specific number of protons and a different arrangement of electrons.

elements

There are _______ naturally occuring elements.

92

In molecules, the atoms are held together by ________ bonds

chemical

The _____ of water molecules determines its chemistry and thus the chemistry of life.

polarity

______ is defined as the negative logarithim of the hydrogen ion concentration in the solution

pH

A substance that acts as a reservoir for H+ irons, opposing any increase or decrease in concentration, is a ________.

buffer

Atoms are composed of electrons and a dense nucleus which contains protons and _________.

neutrons

Carbon-12, carbon-13, and carbon-14 are examples of __________.

isotopes

Organisms are composed of molecules, which are collections of smaller units, called __________.

atoms

Elements that have atoms with the same atomic numbers but different numbers of neutrons are called:

isotopes

In chemical reactions, the gain of an electron is called:

reduction

Water molecules are polar with ends that exhibit partial positive and negative charges. Such opposite charges make water molecules attract ech other through bonds called:

hydrogen bonds

A proton:

a, b, and c are true. Has one positive charge, has one Dalton of mass, and is found in the nucleus of the atom

An electron:

a, b, and c are true. Has one negative charge, has 1/1840 Dalton of mass, is found in an area around that nucleus, called the orbital

The atomic number of an element is equal to the number of:

protons only

Ordinary oxygen has an atomic mass of 16 and an atomic number of 8. This means that the number of neutrons in this type of oxygen is:

8

Which of the following is true about orbitals?

a and b only, they are paths around the nucleus in which the electrons orbit, They cannot contain more than two electrons

A hydrogen molecule formed by sharing a pair of electrons between two atoms is stable for which of the following reasons?

a, b, and c, it has no negative net charge, the octet rule is satisfied, and it has no unpaired electrons

Oxygen ordinarly has 8 protons and 8 neutrons. Another rare form has two extra neutrons. These two forms are:

oxygen isotopes

Atoms in which the number of electrons does no equal the number of protons are known as:

ions

The area around a nucleus where an electron is most likely to be found is called:

an orbital

Regardless of its shape, a given orbital may contain no more than:

2 electrons

Mendeleev arranged the known elements according to their atomic mass, leading up to:

periodic table

All atoms tend to fill their outer energy levels with the maximum number of electrons, usually eight. Depending on whether the atoms satisfied this simple octet rule or not will allow the prediction of:

chemical behavior of the atoms

Sodium has 11 electrons arranged in three energy levels. The outer level has only one electron. In order to become stable, the atom loses an electron thus exposing the previous level with 8 electrons and subsequently becomes and ion with:

1 positive charge

In the crystal matrix of ordinary salt, the sodium and chlorine are held together by:

ionic bonds

Products are made in chemical reactions involving the shifting of atoms of one molecule to another in substances called:

compounds

Chemical reactions can be influenced by:

a, b, and c, temperature, concentration of reactants and products, catalysts

Two carbon atoms might be joined to each other by the sharing of two pairs of electrons, forming:

a double bond

Which of the following is not one of the four most abundant (more than 99%) atoms found in living things?

phosphorus

Life is thought to have evolved from complex molecules formed by the interaction of smaller molecules in oceans and the atmosphere. The substance which brought these molecules together to interact is:

water

Because oxygen is more electronegative than hydrogen, the water molecule is:

polar

Water molecules are attracted to each other because of the opposite charges created by partial charge separations within the molecules. These attractions are called:

hydrogen bonds

Water is extremely important in living things for all of the following reasons except:

it is a highly energetic dietary requirement

Nonpolar molecules tend to aggregate in water because they are forced to come into close proximity with each other due to:

hydrophobic interactions

When water ionizes, it produces equal amounts of hydrogen and hydroxide ions, which can reassociate with each other. Water is thus:

a base and an acid

compared with a pH of 7, a solution of pH 5 has:

100 times the hydrogen concentration

The half life of Carbon is 5, 600 years. 2 grams of carbon-14. age of wood is 22, 400 years, how much carbin-14 originally existed in the wood?

16 grams

The positive side of one water molecule is attracted to the negative side of another water molecule, forming a hydrogen bond. Which of the following pure water properties reflects this type of bonding?

the ability to travel through xylem tubes in a plant's vascular system

Suppose ice were most dense at zero degrees centigrade. Select the best explanation of what would happen in aquatic systems

the ice would cover the bottom of the aquatic system and would build up in layers over time, especially in colder climates

Using the information from the previous question, you also know that acidosis means that:

your dog's blood pH has moved toward the acidic end of the pH scale and has a lower pH value than normal.

She asks you what a radioactive isotope is and you respond correctly using which of the following choices?

Radioactive isotopes are atoms that are unstable and as a result emit energy in a process called radioactive decay

What solution would you propose to keep the reaction moving along quickly?

add more reactants

Covalents bonds: single, double, triple:

Covalent bonds are bonds between atomes in which the atoms shares pairs of electrons. for example, a single bond involves one pair of electrons, etc...

capilary action is a result of water molecules:

having a strong cohesive force and attaching to the surrounding vessel walls

Which of the following is not a property of water?

buffer

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set