Basics of Chemistry

Matter

anything that has mass and takes up space

Mass

measure of the amount of matter in an object

Element

substance that cannot be broken down into other substances by chemical reactions; composed of atoms with same chemical properties

Chemical element

basic building block of matter

Number of essential elements in humans

25 out of 92 naturally occurring

Main body elements

oxygen

Trace elements

required in small amounts for life

Iodine

deficiency causes goiter

Fluorine

strengthens tooth enamel; added to water and dental products

Compound

substance with 2 or more elements in fixed ratio

Molecule

group of atoms covalently bonded in fixed ratio

Atom

smallest unit of matter retaining element properties

Proton

positively charged particle

Electron

negatively charged particle

Neutron

neutral particle

Nucleus

central core of atom

Atomic number

number of protons

Mass number

protons + neutrons

Atomic mass

average mass number of all atoms in sample

Isotope

same protons/electrons

Radioactive isotope

nucleus decays spontaneously

Radon

radioactive gas causing lung cancer

Chemical bond

attraction holding atoms together

Ionic bond

formed between oppositely charged ions

Ion

atom/molecule with electrical charge from gaining/losing electrons

Ionic compound

compound held together by ionic bonds

Covalent bond

atoms share electrons; strongest bond

Chemical reaction

change in chemical composition of matter

Reactants

starting materials in a chemical reaction

Products

end materials in a chemical reaction

Law of conservation of matter

matter cannot be created or destroyed

Polar molecule

molecule with uneven charge distribution

Hydrogen bond

weak attraction between polar molecules

Cohesion

water molecules stick to each other via hydrogen bonds

Surface tension

difficulty in stretching/breaking liquid surface

Adhesion

water molecules stick to other substances

Capillary action

cohesion + adhesion pull water upward

High specific heat

resists temperature change

Evaporative cooling

evaporation lowers surface temperature

Ice density

less dense than liquid water; floats

Importance of floating ice

insulates water below and allows life to persist

Solution

homogeneous mixture of substances

Solvent

dissolving agent in a solution

Solute

dissolved substance in a solution

Aqueous solution

solution where water is the solvent

Universal solvent

water dissolves many substances; medium for reactions

Acid

releases H+ in solution

Base

accepts H+

pH scale

measures H+ concentration

Buffer

minimizes pH changes

Buffer function

accepts H+ when excess

Ocean acidification

CO2 dissolves in seawater forming acid

Organic compound

contains carbon bonded to hydrogen

Carbon bonds

up to 4 covalent bonds

Functional group

atoms directly involved in chemical reactions

Macromolecule

large molecule essential for life

Four macromolecule types

carbohydrates

Carbohydrate

sugar or polymer of sugar

Monosaccharide

single sugar unit; monomer of carbs

Glucose

main fuel for cellular work

Fructose

sugar in fruit

Isomer

same formula

Disaccharide

two monosaccharides linked by dehydration reaction

Sucrose

table sugar; main plant carbohydrate

Lactose

sugar in milk

Maltose

sugar in malted products

High-fructose corn syrup

glucose converted to fructose for sweetness

Polysaccharide

long chain of monosaccharides

Starch

plant energy storage

Glycogen

animal energy storage in liver/muscle

Cellulose

plant cell wall structure; dietary fiber

Hydrophilic molecule

dissolves readily in water

Lipid

hydrophobic molecule

Triglyceride

glycerol + 3 fatty acids

Saturated fat

max hydrogens; solid at room temp

Unsaturated fat

double bonds; liquid at room temp

Hydrogenation

adds hydrogen; creates trans fats

Steroid

4 fused carbon rings

Cholesterol

cell membrane component; base for other steroids

Anabolic steroid

synthetic testosterone variant

Steroid abuse effects

serious physical and mental problems

Protein

polymer of amino acids

Amino acid

monomer of proteins; central carbon + amino group + carboxyl group + hydrogen + R-group

Peptide bond

links amino acids

Polypeptide

chain of amino acids

Protein shape

determines function

Sickle-cell disease

caused by single amino acid substitution in hemoglobin

Prion

misfolded protein causing brain disease

Denaturation

loss of protein shape → loss of function

Enzyme

protein that speeds up reactions

Factors affecting enzymes

temperature

Nucleic acid

stores info; instructions for proteins

DNA

double-stranded; bases A

RNA

single-stranded; bases A

Nucleotide

sugar + phosphate + base

Gene

DNA segment coding for protein

Base pairing

A–T

Sugar-phosphate backbone

structural framework of DNA/RNA

DNA structure

double helix

RNA sugar

ribose