Chapter 2

The formula for methane gas is CH4. What does the formula 4CH4 represent?

4 molecules, each containing a carbon atom and 4 hydrogen atoms

Molecular weight for NaCl

54.8g/mol

The chemical notation that indicates concentration is represented as

[ ].

In chemical notation, the symbol Ca2+ means

a calcium ion has lost 2 electrons

Ionic bonds, such as in sodium chloride,

are formed by the association of ions with opposite charges

Elements that have atoms with full outer shells of electrons

are inert gases

The reaction HCl + NaOH → H2O + NaCl is what type of reaction?

exchange

In an aqueous solution, sodium ions would move toward

negative terminal

Oxygen, which forms naturally as two atoms, are bonded together with what type of bond?

non polar covalent

Radioisotopes have unstable

nuclei

Which of these lists contains only trace elements?

silicon, fluorine, tin

In hydrolysis reactions, compounds react with

water, causing decomposition

If an atom loses an electron, it becomes a __________.

positively charged cation

Which number represents the greatest amount of energy that must be overcome during the reaction? Which number represents the lowest amount of reaction energy? (Figure 2-9)

2;4

Hydrogen bonds are strong attractive forces between hydrogen atoms and negatively charged atoms.

False

How do ions form ionic bonds?

Ions of opposite electrical charges are attracted to each other to balance the charges.

When a small amount of HCl or NaOH is added to a solution of Na2HPO4, the pH of the solution barely changes. Based on these observations, all of the following are true concerning the compound Na2HPO4, except

Na2HPO4 adsorbs excess H+ and OH- directly onto the surface of its crystalline structure.

Which of the following distinguishes hydrogen bonds from covalent bonds?

Only hydrogen bonds can form between molecules

On a camping trip, you are sitting by a pond, watching the fire. You observe a particle of ash fall and hit the surface of the water. It sits there for a moment before sinking and dissolving. Why was it able to sit there for a few seconds?

The surface tension created by the hydrogen bonds between water molecules kept it from entering the water.

Which of the following is not a result of hydrogen bonds?

Two hydrogen atoms join together to form a molecule of hydrogen gas.

ionic bonds form when

an electron or electrons are completely transferred from one atom to another

In an aqueous solution, cations are attracted toward

anions

ions in an ionic molecule are held together due to

attraction of opposite electrical charges

In an ionic bond, the electron donor is the ________, whereas the electron acceptor is the ________.

cation; anion

ions with + charge

cations

H2O is an example of a(n)

compound

When atoms complete their outer electron shell by sharing electrons, they form

covalent bonds

The reaction A + B + energy → AB is an example of a(n) ________ reaction.

endergonic

During ionization, water molecules disrupt the ionic bonds of a salt to produce a mixture of ions. These ions can carry a current and so are called

electrolytes

Soluble inorganic compounds whose solutions will conduct an electric current are called

electrolytes

A molecule that has unpaired electrons is a(n)

free radical

Oppositely charged ions in solution are prevented from combining by

hydration spheres

The electrostatic attraction between the slight positive charge of a hydrogen of one molecule and the slight negative charge of an oxygen, nitrogen, or fluorine of another molecule is called a(n)

hydrogen bond

Nonpolar organic molecules are good examples of

hydrophobic compounds

In any given molecule, the sum of the atomic weights of its component atoms is called

molecular weight

The chemical behavior of an atom is determined by the

outermost electron shell

If a pair of electrons is unequally shared between two atoms, a(n) ________ bond occurs.

polar covalent

What type of chemical bond holds the atoms in a water molecule together?

polar covalent bonds

In a molecule of nitrogen, three pairs of electrons are shared by two nitrogen atoms. The type of bond that is formed is an example of a ________ bond.

triple covalent