Chem Ch. 5.3-6

Question 1

Mole

Answer 1

Is an amount of any substance or item that contains the same number of elementary units as there are atoms in exactly 12g of carbon-12.

Question 2

Formula mass

Answer 2

The sum of masses of the atoms represented in the formula

Question 3

Molar mass

Answer 3

The mass of one mole of that substance.

The molar mass is numerically equal to the atomic mass, molecular mass, or formula mass, but it is expressed in the unit grams per mole. (g/mol).

Ex: atomic mass of sodium 23.0 u, son it’s molar mass is 23.0 g/mol; the molecular mass of carbon dioxide is 44.0 u, its molar mass is 44.0 g/mol; the formula mass for ammonium sulfate is 132.1 u, so its molar mass is 132.1 g/mol

1 mol Na = 23.0 g Na
1 mol CO2 = 44.0 g CO2
1 mol (Nh4)2SO4 = 132.1 g (Nh4)2SO4

Question 4

Avogadro’s number

Answer 4

6.02 x 10^23

Question 5

Stoichiometry

Answer 5

The quantitative relationship between reactants and products in a chemical reaction.

Question 6

Solution

Answer 6

A homogeneous mixture of two or more substances.

The substance being dissolved is the solute, and the substance doing the dissolving is the solvent.

Question 7

Molarity

Answer 7

The amount of solute, in moles, per liter of solution.

Molarity (M)= moles of solute / liters of solution

Question 8

Solubility

Answer 8

Maximum quantity of a given solute that can dissolve in any given kind of solvent at a specific temperature. (Solubility can increase, stay the same, or decrease with an increase in temperature depending upon the substance in question.)

Question 9

Insoluble

Answer 9

A substance that can not be dissolved in any given solvent (potentially imprecise term.)

Question 10

mM

Answer 10

The amount of dissolved substance in units of one thousandth of a mole per liter.

Question 11

MW

Molecular weight/molar mass

Answer 11

Mass in grams of one mole of any substance

Question 12

Valence electrons

Answer 12

Electrons in the outermost shell.

Question 13

Electronegativity

EN

Answer 13

The relative tendency of an atom to attract or draw electrons to itself.

Question 14

Ionic compounds

Answer 14

Compounds composed of positive and negative ions and held together by ionic bonds.

Ionic bonds- Strong chemical bond formed by the attraction between two oppositely charged ions. ie: between positively charged cation and negatively charged anion.
Cation- lost 1 or more electrons
Anion- gained 1 or more electrons

Question 15

Formula unit

Answer 15

Smallest repeating unit of a salt.

Question 16

Salt

Answer 16

Ions must be paired with oppositely charged ions. The resulting electrically neutral compound is called a salt.

Salts form by complete transfer of electrons from a cation to anion

Question 17

Polyatomic ion

Answer 17

A positive or negative ion composed of two or more atoms.

*Polyatomic ion formula enclosed in parentheses when more than one is present

Question 18

Non-bonding pairs

Lone pairs

Answer 18

Valence electrons in a molecule that aren’t in a bond between atoms; have significance in chemical reactions, so need to be noted.

Question 19

“-ide”

Answer 19

Names of simple negative ions (anions) are derived from those of their parent elements by replacing the usual ending with a suffix “-ide” And adding the word ion.

Ex: when chlorine atom gains an electron, it becomes a chloride ion (Cl^-).

Question 20

Free radical

Answer 20

And atom or molecule that contains an unpaired electron

Question 21

Hydrocarbons

Answer 21

A class of organic molecules that contain only carbon and hydrogen.

(methane is simplest hydrocarbon possible).

Question 22

Alcohols

Answer 22

A class of organic molecules related to hydrocarbons where at least one hydrogen was replaced by a hydroxide ion.

(Small alcohols tend to be more polar than non-polar, so are soluble in water.)

Question 23

Metallic bonding

Answer 23

Occurs between metals.

• metals achieve a noble gas electron configuration by losing electrons, but without an electron receptor.
• Electrons formed by ionization of a metal “float around” in a “sea of charge” and neutralize positive charge of individual metal ions.

Question 24

“-per”

Answer 24

Prefix meaning one more oxygen than the -ate. 
Hypo-
-ite
-ate
Per-
—

Question 25

“Hypo-“

Answer 25

Prefix meaning one less oxygen than the -ite. 
Hypo-
-ite
-ate
Per-
—

Question 26

Vapor pressure

Answer 26

The increase in pressure above a liquid caused by molecules of that substance that have escaped from the liquid. (relative humidity is derived from vapor pressure)

Vapor pressure increases with increasing temperature.

Question 27

Boiling point

Answer 27

Temperature at which vapor pressure of a liquid equals atmospheric pressure.

Question 28

Volatile

Answer 28

Easily vaporized substances.

Question 29

Evaporation (related to vaporization)

Answer 29

Individual molecules at surface of a liquid acquire enough energy to escape; slower than boiling; can occur at temperatures well below boiling point.

Question 30

Condensation

Answer 30

The change in the physical state of a substance from the gaseous phase into a liquid.

Question 31

Melting point

Answer 31

Temperature at which a solid turns into a liquid.

Question 32

Dipole

Answer 32

Polar covalent molecules have partial positive and negative ends that are attracted to one another. Example: water

Question 33

Hydrogen bonding

Answer 33

When a hydrogen atom covalently bonded to a strongly electronegative atom with non-bonding electron pairs. Main elements where this occurs: O, N and F. H will lose a little of its negative charge to bond with O, N & F.

Question 34

Solutions

Answer 34

Homogenous mixtures of two or more substances, often a liquid one.

Question 35

Hydrated

Answer 35

When water molecules pack around each ion as tightly as possible. => ions become hydrated. Process known as hydration.

Question 36

Specific heat capacity

Answer 36

The amount of heat required to raise 1g of a substance 1 degree celsius

Question 37

Saturated

Answer 37

When limit reached, the water has absorbed all the ions it can and the solution has become saturated.

At the point of saturation, salt crystals will appear at the bottom of the solution.

Question 38

Precipitation

Answer 38

Condensation of a solid from a solution during a chemical reaction.

Dissolved substance becoming a solid.

Question 39

Miscibility

Answer 39

Ability to mix with other gases in any proportions; i.e., there is always room for more molecules of any kind.

Gases mix due to random molecular motion.

Question 40

Sublimation

Answer 40

The transition from the solid phase to the gas phase without passing through an intermediate liquid phase.

This endothermic phase transition occurs at temperatures and pressures below the triple point.