quiz 2

solid

definite shape and volume

liquid

definite volume and changeable shape

gas

changeable shape and volume

conversions energy is lost as ___

heat

physical elements

detected with senses

chemical elements

atom interaction

major elements of the body

oxygen,carbon,hydrogen,nitrogen

how much does mass of O,C,H,N is in our bodies?

96%

electrons

orbit around nucleus (negative charge)

planetary model

electrons move around the nucleus in circular orbits

orbital model

regions around the nucleus in which electrons are most likely to be found

atomic #

number of protons

mass #

proton + neutrons

atomic weight

average mass number of all isotops

isotope

atoms with same number of protons but different number of neutrons

molecule

2+ atoms held together by chemical bond

compound

2+ different atoms chemically bonded. Can’t be separated (homogenous)

mixtures

can be separated (hetero/homogenous)

reactive

unbalanced valence shell

ionic bond

attraction between two opposite charged ions: cation+anion. ex: NaCl

anion

gain (e-)= negative

cation

lose (e-)= positive

ionic example

NaCl. MgCl2. CaCl2. KCl. NaBr

covalent bond

sharing (e-). can be polar or nonpolar

single bond example

CH4 (methane)

covalent bond example

CH4, H2O, CO2, NH3, O2

electronegative

6 or 7 valence shell electron

electropositive

1 or 2 valence shell electron

hydrogen bonds

can’t bind atom; in dipole (H2O); surface tension in (H2O)

chemical reaction

formed when bonds are formed, rearranged, broken

combination (anabolic)

bond formation (A+B→AB); require energy

decomposition (catabolic)

break bonds (AB→A+B): release energy

exchange

makes & breaks bonds (AB+C→AC+B)

reactant lose (e-)

electron donors; “oxidized”

reactant take (e-)

acceptors “reduced”

exergonic reaction

release energy

endergonic reaction

reaction’s products have more potential energy

organic compounds

contain carbon: covalent bond

inorganic compound

no carbon; H2O; NaCl; acid & base

organic compound examples

carbohydrates, lipids, protein, nucleic acid

carbohydrates

have carbon, hydrogen, oxygen: major function is to supply source of cellular food

carbohydrates examples

(monosaccharides)- glucose, fructose, galactose, deoxyribose, ribose

properties of H2O

high heat capacity, high heat of vaporization, polar solvent properties, reactivity, cushioning

high heat capacity

absorb and release a lot of heat before changing temperature

high heat of vaporization

liquid to gas needs a lot of heat

polar solvent properties

dissolves ionic substances form hydration layers around large charged molecules; body’s main transport medium

reactivity

important in hydrolysis and dehydration synthesis

cushioning

resilient cushion around some body organs

salt

inorganic compound; contain cations and anions; electrolytes; conduct electrical currents

what can influence chemical reaction?

temperature, size, concentration, catalyst, enzyme

temperature-chemical reaction

quicker when high

size-chemical reactions

smaller = quicker

concentration-chemical reacions

higher reacting particle concentration produce faster reactions

catalyts-chemical reactions

increase rate of reaction

acid

release (H+)= proton donors

base

release (OH-)= proton acceptors

acidic

high (H+); pH 0-6.99

alkaline

low (H+) pH 7.01-14

neutral

equal (OH-) (H+) pH 7.0