Chemistry Final Prep #1

Covalent bonds are formed from atoms sharing valence electrons to achieve 8 valence electrons (octet)

In a chemical equation reactants are on the left side of the arrow and products are on the right.

Transition elements need roman numerals because they can have multiple oxidation states (or charges). The roman numerals are needed to identify which oxidation state of the element is in the compound.

Aqueous solutions are made when a compound (solute) is dissolved in water (solvent).

The empirical formula is always the simplest form of a molecule. It has all of the subscripts reduced in the same way you might reduce a fraction. The molecular formula is a multiple of the empirical and represents how the molecule really exists. For example, a molecule may have a formula of C2H6, but the empirical formula would be CH3

Ionic bonds are formed when two atoms give and take electrons to form a cation and anion that are electrostatically attracted.

Cations tend to be metals (from the left side of the stair step)and are positively charged ions that lose electrons to acquire 8 electrons in its outer shell. This process allows for more stability.

Ions are more stable than their neutral form. They are more stable because the gaining or losing of electrons allows them to have 8 valence electrons just like the noble gases.

Hydrates have water bonded within their structure. A hydrate can be a dry-looking solid. When heating a hydrate you can remove the bonded water and make the compound anhydrous (without water).

Single replacement reactions can happen with the replacement of the cation in a compound with another or the replacement of an anion with another. This replacement happens according to the activity series of metals and halogens. If the cation being replaced is less reactive than the one being introduced than the reaction will take place. The product in a single replacement reaction will always contain the more reactive cation/anion.

Alloys can be substitutional or interstitial. Substitutional alloys are alloys that have had some atoms in a metallic crystal replaced by different type(s) of atoms. Interstitial alloys are alloys that have had different atoms placed in the interstitial spaces in the metallic crystal.

Spectator ions are ions in a solution that do not participate in a reaction. They stay in solution as ions before and after the reaction.

Percent yield is a measure of efficiency of a reaction. It is the actual (experimental) yield of a reaction divided by the theoretical (calculated / maximum) yield.

According to the combined gas law, when one of the three variables (temperature, pressure and volume), the other two will change also.

The mole is a number, 6.02 x 10^23. Not unlike a dozen; but much bigger. A mole can measure anything: atoms, molecules, bananas or flowers. The volume and mass of a mole will depend on what you have, but the amount (in numbers) will always be the same.

The limiting reactant is always the reactant that will run out first in the reaction. It may have more or less moles than the excess reactant depending on the mole ratios in the balanced equation. The molar mass of the reactants are not a determining factor.

KMT, or kinetic molecular theory is defined from the assumptions listed in the first three options.

Ionic compounds can conduct electricity when their charged ions are free to move. This can happen when the are in their liquid state or when they are in an aqueous solution.

Absolute zero is the coldest theoretical temperature. It is -273 on the celsius scale and 0 on the Kelvin scale. It is the point at which the volume of a gas is believed to be 0.

Precipitates are insoluble solids that are formed in solution; usually during a double replacement reaction.

metallic bonds are formed from cations "swimming" in a sea of delocalized electrons.

Resonance allows for the formation of equivalent bonds in a molecule. The electrons from the pi bond delocalize and form similar bonds on all sides.