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Biochemistry Notes 1. Bonds, Mixtures, and Reactions or “The Name’s BOND…. Chemical Bond” or “Reactions Speak Louder than Words”. Molecules. Water – H 2 O ( polar bonding ) Molecule = groups of atoms joined together by a chemical bond (atoms bind such that there are excess (-)
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Biochemistry Notes 1 Bonds, Mixtures, and Reactions or “The Name’s BOND…. Chemical Bond” or “Reactions Speak Louder than Words”
Molecules • Water – H2O (polar bonding) • Molecule = groups of atoms joined together by a chemical bond (atoms bind such that there are excess (-) on the oxygen side or excess of (+) charges on the Hydrogen side of the molecule.)
Bonds • Covalent bond – electrons are shared between atoms! (most common bond) • Ex: H2O • Ionic bond – electrons are transferred from one atom to another. • Ex: NaCl
Mixtures- groups of molecules Three types: • Solution – uniform blending of molecules that appears clear • The solute is dissolved in the solvent (often water – known as aqueous solutions) • Ex: salt water, sugar water
Mixtures (con’t) • Suspension – not as well mixed and particles settle out. *Ex: Blood, muddy water *A centrifuge can spin and separate components. *Filters can also be used to separate components.
Mixtures (con’t) • Colloids – “in between” the other two. Aren’t clear, but don’t settle into layers. *Ex: Cytoplasm, Gak Homogeneous: looks the same throughout. Ex: kool-aid Heterogeneous: doesn’t look exactly the same throughout. Ex: ranch dressing
Energy and Chemical Reactions • Potential energy is stored (often in chemical bonds) • Ex: Sugar • Kinetic energy is in motion or use; • Motion determines state of molecules (solid, liquid, gas) • Which state has the least kinetic energy?
Chemical Reactions… • Involve breaking of bonds & formation of new ones. • Chemical equations show this change. • Reactants = “ingredients” (left of arrow) • Products = “result” of reaction (right of arrow) • The arrow sign = “yields” (that’s how you read it!)
“Big” numbers = coefficients; tell how many molecules there are. • How many water molecules are there? • “Little” numbers = subscripts; tell how many atoms in each molecule! • How many atoms of hydrogen are in water? • How many atoms of hydrogen total on the reactants side??
Activation Energy… • “Starter” energy necessary to get a reaction going. Reactions: • EXOTHERMIC – extra energy is released when products are formed! (heat, light, bubbles) • ENDOTHERMIC – absorb energy from environment to make products. (feel cold sometimes)