CHM 1045 Exam #1

chemistry

the study of matter and the changes it undergoes

scientific method

systematic approach to research

hypothesis

temporary explanation for the observation

law

concise statement of a relationship between phenomena that is always the same conditions or standards

theory

principle that explains a basis of facts or laws based on them

homogeneous

constant composition

heterogeneous

nonuniform composition

physical properties

observed without chemically altering the substance; ex: boiling point, melting point

chemical properties

must chemically alter substance in order to observe; ex: combustion, oxidation, reduction

extensive properties

same size dependent; ex: mass, volume

intensive properties

same size independent; ex: density, temperature

tera

1.0 x 10^12

giga

1.0 x 10^9

mega

1.0 x 10^6

kilo

1.0 x 10^3

deci

1.0 x 10^-1

centi

1.0 x 10^-2

milli

1.0 x 10^-3

micro

1.0 x 10^-6

nano

1.0 x 10^-9

pico

1.0 x 10^-12

Conversion to Fahrenheit

= Tc(1.8°F/1.0°C) + 32°F

Conversion to Celsius

= (Tf - 32°F)(1.0°C/1.8°F)

Conversion to Kelvin

= Tc + 273.15

Significant Figure Rules

1. Any non-zero digit is significant.

2. Zeros between non-zero digits are significant.

3. Zeros the the left of the first non-zero digit are not significant.

4. If the number is greater than one, all zeros written to the right of the decimal point are significant.

5. Trailing zeros may or may not be significant. Use scientific notation to clear up confusion.

accuracy

how close a measurement is to a true or accepted value

precision

how closely two or more measurements are to each other (repeatability)

Law of Definite Proportions

different samples of the same compound contain the same proportion (by mass) of its constituent elements

Law of Multiple Proportions

different compounds made up of the same elements differ in the ratio of each atom included

Law of Conservation of Mass

matter can be neither created nor destroyed

Alpha rays

positively charged particles of radiation

Beta particles

negatively charged particles of radiation (glorified electrons)

Gamma rays

particles of radiation with very high energy

atomic number

the number of protons in an element

mass number

the sum of protons and neutrons in an element

isotopes

contain the same number of protons, but different numbers of neutrons

ion

atom or group of atoms that has a charge

ionic compound

contains both cation and anion

Carbide

C⁴-

Silicide

Si⁴-

Nitride

N³-

Phosphide

P³-

Oxide

O²-

Sulfide

S²-

Selenide

Se²-

Telluride

Te²-

Fluoride

F-

Chloride

Cl-

Bromide

Br-

Iodide

I-

molecular formula

formula with the exact number of atoms of each element in the smallest unit of a substance

allotrope

different forms of the same element; ex: O₂ and O₃

empirical formula

formula that shows which elements are present in the smallest, whole-number ratio of their atoms

Al³⁺

Aluminum cation

NH₄⁺

Ammonium cation

Ba²⁺

Barium cation

Cd²⁺

Cadmium cation

Cs⁺

Cesium cation

Cr³⁺

Chromium (III) cation

Co²⁺

Cobalt (II) cation

Cu⁺

Copper (I) cation

Cu²⁺

Copper (II) cation

H⁺

Hydrogen cation

Fe²⁺

Iron (II) cation

Fe³⁺

Iron (III) cation

Pb²⁺

Lead (II) cation

Li⁺

Lithium cation

Mg²⁺

Magnesium cation

Mn²⁺

Manganese (II) cation

Hg₂²⁺

Mercury (I) cation

Hg²⁺⁺

Mercury (II) cation

K⁺

Potassium cation

Rb⁺

Rubidium cation

Ag⁺

Silver cation

Na⁺

Sodium cation

Sr²⁺

Strontium cation

Sn²⁺

Tin (II) cation

Zn²⁺

Zinc cation

Br⁻

Bromide anion

CO₃²⁻

Carbonate anion

ClO₃⁻

Chlorate anion

Cl⁻

Chloride anion

CrO₄²⁻

Chromate anion

CN⁻

Cyanide anion

Cr₂O₇²⁻

Dichromate anion

H₂PO₄⁻

Dihydrogen phosphate anion

F⁻

Fluoride anion

H⁻

Hydride anion

HCO₃⁻

Hydrogen carbonate anion

HPO₄²⁻

Hydrogen phosphate anion

HSO₄⁻

Hydrogen sulfate anion

OH⁻

Hydroxide anion

I⁻

Iodide anion

NO₃⁻

Nitrate anion

N³⁻

Nitride anion

NO₂⁻

Nitrite anion

O²⁻

Oxide anion

MnO₄⁻

Permanganate anion

O₂²⁻

Peroxide anion

PO₄³⁻

Phosphate anion