CHEM130 - Exam 1

Flashcards leading up to exam 1.

3 Properties of a Quantity

• Magnitude

• Unit

• Uncertainty

Prefix for 10³

kilo (k)

Prefix for 10^-2

centi (c)

Prefix for 10^-3

milli (m)

Prefix for 10^-6

micro (µ)^a

Prefix for 10^-9

nano (n)

Prefix for 10^-12

pico (p)

1.00 in = ? cm

2.54 cm

1.00 lb = ? g

453.5 g

1.000 kg = ? lb

2.205 lb

1.000 L = ? qt

1.057 qt

1.00 qt = ? L

0.946 L

Chemistry

The study of matter and the changes it undergoes.

Observation

A collection of information that will be used to form testable hypotheses.

Hypothesis

Tentative, testable explanation for an observation.

Law (scientific law)

Repeatedly tested hypothesis that has not been contradicted.

Theory (scientific theory)

A unifying principle that explains facts and laws. They are continuously revised as new data is obtained.

Chemical v. Physical properties and changes

Chemical: A property of a substance that can be observed only by reacting the substance with something else to form another substance.

• Oxidation states

• Heat of Combustion

• Reactivity

Physical: A property of a substance that can be observed without changing the substance into another substance.

• Length

• Density

• Volume

Base SI units

Time

• Second, s

Length

• Meter, m

Mass

• Gram, g

Electric current

• Ampere, A

Thermodynamic temperature

• Kelvin, K

Amount of substance

• Mole, mol

Luminous intensity

• Candela, cd

Precision

How closely grouped are repeated measurements to one anotherr.

Accuracy

How close is a measurement to the known or accepted value.

Systemic Error

A consistent offset in measurement.

Random Error

Inconsistent deviation, often due to experimenter, can sometimes be attributed to “noise” from an instrument (random variation in signal)

Postulates of Dalton’s Atomic Theory

• All matter consists of indivisible particles called atoms.

• Atoms of the same element are similar in shape and mass but differ from atoms of other elements.

• Atoms cannot be created or destroyed.

• Atoms of different elements may combine with each other in a fixed, simple, whole number ratio to form compound atoms.

• Atoms of the same element can combine in more than one ratio to form two or more compounds.

• The atom is the smallest unit of matter that can take part in a chemcial reaction.

Law of Conservation of Mass

Mass before reaction = Mass after reaction. Matter is neither created nor destroyed.

Law of Definite Proportions

Compound always contains the same elements in the same proportions by mass.

Law of Multiple Proportions

Elements may combine in two or more sets of proportions, each a different compound.

Protons

Subatomic particles contained in the nucleus, positively charged.

Neutrons

Subatomic particles contained in the nucleus, electronically neutral.

Electrons

The first discovered subatomic particle. Negatively charged particles with constant mass-to-charge ratio.

Defining Elements

Elements are defined by their number of protons.

Isotope

Atoms of an element containing the same number of protons, but different numbers of neutrons.

Atomic Mass Unit

A unit approximately equal to the mass of 1 proton. 1 amu = 1.661 × 10^-24 g.

Average Atomic Mass

Equal to the sum of the abundances of an isotope times its mass.

Mole

The number of atoms in 12 g of isotopically pure carbon-12. A conversion factor that provides a direct relationship between amu and grams. Atomic mass (amu) = molar mass (g/mol).

Relationship between Mass, Moles, and Number of Atoms

Atomic mass = molar mass.

Alkali Metals

Group 1 of the Periodic Table

Alkaline Earth Metals

Group 2 of the Periodic Table

Transition Metals

Groups 3-12 of the Periodic Table

Noble Gases

Group 18 of the Periodic Table

Halogens

Group 17 of the Periodic Table

Categories of Chemical Compounds

• Molecular, binary, non-acid

• Molecular, binary, acid

• Molecular, oxoacids

• Ionic, oxoanions

Naming molecular, binary, non-acid compounds

First word is the name of the first element. The ending of the name of the second element should be -ide. Use prefixes to indicate the numeber of each atom (only use prefixes for the first element if > than 1).

Naming molecular, binary, acid compounds

Only consists of hydrogen and one other element. Add the prefix hydro- to the name of the second element. Replace the last syllable in the second element with -ic followed by acid.

Naming molecular, oxoacids (polyatomic ions)

An ionic compound with a polyatomic anion is named by simply stating the name of the cation and the polyatomic anion. If the compound has ammonium, follow the same rules for normal binary ionic compounds. If the element forms more than one oxoanion, prefixes and sufixes are used to differentiate the O.N. of that element.

If ending is -ate, the name of the oxoacid ends with -ic.

If ending is -ite, the name of the oxoacid ends with -ous acid.

Identify the Different Types of Formulas

• Molecular Formula: states the actual number of atoms of the elements in a single molecule.

  • i.e., C₆H₁₂O₆

• Empirical Formula: simplest ratio of the whole number of elements in a compound.

  • i.e., CH₂O

• Structural Formula: shows the chemical bonds of a molecule.

• Condensed Structural Formula: a combination of molecular and structural formulas that shows the actual number of atoms of each element, and the bonds to hydrogen atoms.

  • C₄H₁₀ —> CH₃CH₂CH₂CH₃

Ionic Compounds

A substance formed of positive and negative ions joined together by electrostatic forces of attraction (opposite charges attract).

Molecular Compound

A substance made of discrete units called molecules, typically consisting of a small number of nonmetal atoms bonded together.

Polyatomic Ion

An ion that consists of two or more atoms joined together by covalent bonds.

Oxoanion

A polyatomic ion containing at least one nonoxygen central atom bonded to one or more oxygen atoms.

Ammonium ion

NH₄⁺

Acetate ion

CH₃COO^-

Carbonate ion

CO₃^2-

Hydrogen carbonate ion

HCO₃^-

Hypochlorite ion

ClO^-

Chlorite ion

ClO₂^-

Chlorate ion

ClO₃^-

Perchlorate ion

ClO₄^-

Chromate ion

CrO₄^2-

Dichromate ion

Cr₂O₇^2-

Cyanide ion

CN^-

Hydroxide ion

OH^-

Nitrite ion

NO₂^-

Nitrate ion

NO₃^-

Oxalate ion

C₂O₄^2-

Permanganate ion

MnO₄^-

Phosphate ion

PO₄^3-

Sulfite ion

SO₃^2-

Sulfate ion

SO₄^2-

Thiosulfate ion

S₂O₃^2-