Exam 2 Review Flashcards
Compounds are composed of atoms held together by…
Chemical bonds.
Ionic Bonds occur… and involve the…
Between metals and nonmetals; transfer of electrons.
In an ionic bond, the metal becomes … and the nonmetal becomes…
A cation; an anion.
Why do metals tend to form cations?
They have low ionization energies and low electron affinities.
Why do nonmetals tend to form anions?
They have high ionization energies and high electron affinities.
Covalent bonds occur….and involve the…
between two nonmetals; sharing of electrons.
Covalently bound atoms are called…
Molecular compounds.
Ionic compounds are usually…at room temperature.
Solid.
Covalent compounds are usually…at room temperature.
Solids, liquids, or gases.
Which representation of a hydrogen molecule is not correct?
- H2
- H:H
- H–H
- H=H
H=H.
An empirical formula…
Gives the relative number of atoms of each element in a compound.
A molecular formula…
Gives the exact number of atoms of each element in a compound.
What is the empirical formula of C4H8?
CH2.
What is the empirical formula of CCl4?
CCl4.
What is the empirical formula of B2H6?
BH3.
In the chemical formula of an Ionic compound…
the charge of the cations must equal the charges of the anions.
How to name binary compounds:
Name of the metal + base name of the nonmetal, ending in IDE.
How to name multivalent compounds (steps):
- Observe the charge of the nonmetal.
- Find what charge of the metal will make the total charge 0.
What is an oxyanion?
An oxyanion is an anion containing oxygen and ONE other element.
When naming ionic compounds containing polyatomic ions…
The name of the metal is used, followed by the name of the polyatomic ion.
Name NaNO2.
Sodium nitrite.
The formula for the carbonate ion is…
CO3^2-
The formula for the hydroxide ion is…
OH-
The formula for nitrate is…
NO3-
The formula for the ammonium ion is…
NH4+
When naming molecular compounds…
The element with the SMALLEST group number first.
What is the formula used to find the percentage of each element in a compound?
the molecular mass of element Z
———————————————- mass of 1 mol of compound x 100
= % mass of element Z
Finding an empirical formula (steps):
- Convert percentages to grams. If not given, assume you have 100 g of the compound. (e.g. 25.5% –> 25.5 g)
- Covert grams to moles. (Mass of element Z x ( 1 mol of Z / molar mass of Z ) = moles of Z)
- Divide by the SMALLEST NUMBER OF MOLES.
- Multiply mole ratios by any number to make all whole numbers.
Whenever something burns it combines with…
O2.
Define theoretical yield.
The amount of product that can be made based on the amount of the limiting reactant.
Formula for percent yield.
% yield =
actual yield / theoretical yield x 100
The majority component of a solution is the…
Solvent.
The minority component of a solution is the…
Solute.
A solution in which water is the… is a…
Solvent; aqueous.
Dilute solutions have…
A small amount of solute compared to solvents.
Concentrated solutions have…
A large amount of solute compared to solvents.
Molarity (.) is used to express…
M; solution concentration.
The formula for molarity is…
M = amount of solute (in mol) /
volume of solution (in L)
Formula (stock solutions)…
M1 x V1 = M2 x V2
Define electrolyte.
A substance that dissolves in WATER to form a solution containing IONS that WILL CONDUCT ELECTRICITY.
Define a nonelectrolyte.
Substances that dissolve in water to form a solution with NO IONS that will NOT conduct electricity.
A strong electrolyte…
Completely ionizes in water.
Most molecular compounds are… when dissolved in water.
Nonelectrolytes.
When compounds contain THESE elements they are ALWAYS soluble.
Li+, Na+, K+, NH4+ (LINAK NH4). NO3- and C2H3O2- (NO CHO).
