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2-1 2-2 2-3 2-4 Left -overs

Atoms of the same element with different numbers of neutrons

isotopes

Combination of two or elements in definite proportions

Compound

Bond formed when one or more electrons are transferred from one

atom to another

Ionic bond

Bond formed when electrons are shared between atoms

Covalent bond

Attraction between slightly charged regions of molecules

Van der Waals forces

Attraction between molecules of the same substance

cohesion

Substance in which a solute dissolves

solvent

Solution with a higher concentration of hydrogen ions

than water

acid

Weak acid or base that can react with strong acids or bases to

prevent sharp, sudden changes in pH

Buffers

Compound that produces hydroxide ions in solution

base

Smaller units that are joined together to form polymers

monomers

Compound made of carbon, hydrogen, and oxygen atoms

Carbohydrate

Compound made mostly of carbon and hydrogen atoms

Lipid

Macromolecule containing hydrogen, oxygen, nitrogen,

phosphorous, and carbon

Nucleic acid

Macromolecule that contains nitrogen, carbon, hydrogen, and

oxygen

Protein

Process that changes one set of chemicals into another set of

chemicals

Chemical reaction

Elements or compounds produced by a chemical reaction

products

Energy needed to get a reaction started

Activation energy

Substance that speeds up the rate of a chemical reaction

Catalyst

Protein that acts as a biological catalyst

Enzyme

Elements or compounds that enter into a chemical reaction

reactants

Scale that measures the concentration of hydrogen ions in a

solution

pH scale

Mixture in which all components are evenly distributed

solution

Attraction between molecules of different substances

adhesion

Uneven of distribution of electrons between atoms in a molecule

polarity