The smallest particle of an element that has the chemical properties of the element.
Three subatomic particles: Protons: + charge Neutrons: no charge Electrons: - charge; in constant movement around the Nucleus # protons = # electrons, so the atom is neutral overall. Amazing Atoms Equal mass; Found in the Nucleus
A pure substance that consists entirely of one type of atom. Listed on the periodic table. Ex: hydrogen (H)
Contain same number of protons & electrons (so are the same element), but have a differing number of neutrons. Ex: carbon-12 & carbon-14
Two or more elements chemically combined together. The chemical and physical properties of a compound are different than the properties of the individual elements from which it is formed. ▪ Ex: NaCl
Two types: Ionic: Electrons are transferred from one atom to another; creates ions ▪ Ions: charged atoms ▪ Ex: Na+, Cl- Covalent: Electrons are shared (travel around both nuclei); creates molecules ▪ Molecules: smallest unit of a compound with covalent bonds ▪ Ex: H2O (2 atoms of H, 1 atom of O)
Composed of two or more elements or compounds. NOT chemically combined. Solution: a mixture with components evenly distributed throughout Two parts: Solute: the part that is dissolved Solvent: the part that is dissolving
Acids: form H + ions in a solution pH = 1-7 Bases: form OH - in a solution pH = 7-14 Buffers: weak acids or bases that react with strong acids or bases to prevent sudden changes in pH Help maintain homeostasis!
Carbon has 4 electrons for bonding, so it can form strong covalent bonds with many other elements (like H, O, P, S, and N). Carbon can form single, double and triple bonds with itself. Organic = contains Carbon
Monomers: smaller unit Polymers: larger compound Types of Macromolecules: carbohydrates, lipids, nucleic acids, proteins
Chemical CompositionExamplesFunction in Living Things -C, H, O- monosaccharides: simple sugars ( glucose, fructose, galactose) - polysaccharides: complex sugars (glycogen, starch) - Main source of energy. - Structural purposes in some cells (cellulose in plants).
Chemical CompositionExamplesFunction in Living Things -C, H, O - Glycerol + fatty acid -fats, oil, waxes -saturated: all single bonds (animal fats = bad!) -unsaturated: at least one double bond (vegetable fats = good!) -Stored energy. -Membranes & waterproof coverings. -Chemical messengers (steroids).
Chemical CompositionExamplesFunction in Living Things -C, H, O, N, P - sugar + phosphate group (P) + nitrogenous base (N) - polymers of nucleotides - DNA, RNA- Store & transmit genetic information.
Chemical CompositionExamplesFunction in Living Things -C, H, O, N, S - polymers of amino acids - enzymes- Control reactions (enzymes) & cell processes. - Transport materials in & out of cells. - Fight disease (antibodies).
When one set of chemicals changes into another set of chemicals. CO 2 + H 2 O H 2 CO 3 Chemical reactions always involve the breaking of bonds in the reactants and the formation of new bond in the products.
CO 2 + H 2 O H 2 CO 3 Reactants: elements or compounds that enter into a reaction Ex: CO 2 & H 2 O Products: elements or compounds that are produced by a reaction Ex: H 2 CO 3
2 HCl + 2 Na -> 2 NaCl + H 2 Remember the 2 after H 2, means that there are 2 atoms of H in this molecule. (For H 2 O, there are 2 atoms of H and 1 atom of O.) The 2 in front of 2 HCl, means that there is 2 of the entire molecule, so 2 atoms of H and 2 atoms of Cl.
Reactions that release energy often occur spontaneously. Reactions that absorb energy will not occur without a source of energy. Activation Energy: the energy needed to get a reaction started
Catalyst: a substance that speeds up the rate of a chemical reaction by lowering the activation energy. Enzymes: proteins that act as catalysts in cells. Substrates: the reactants of an enzyme- catalyzed reaction Active site: spot on the enzyme where the substrate binds
Temperature, pH and regulatory molecules can affect the activity of enzymes. Video
Dehydration synthesis: two molecules bond together & H 2 O is made Used to make polysaccharides, lipids & proteins Hydrolysis: H 2 O is used to split two molecules