Criado por fatimaiqbal101
quase 10 anos atrás
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Questão | Responda |
4 elements that make up 96% of living matter | carbon oxygen hydrogen nitrogen |
4 elements that make up the remaining 4% | phosphorus calcium sulfur potassium |
weak bonds | hydrogen bonds hydrophobic & hydrophilic interaction van derwaals forces |
strong bonds | covalent bonds |
covalent bond | a shared pair of electrons stable bond |
multiple covalent bonds | double bonds triple bounds |
non polar covalent bond | pair of electron shared equally by 2 atoms |
polar covalent bond | pair of electrons shared unequally by 2 atoms ex. water + and - poles |
hydrogen bonding | polar water creates molecular attractions attraction between + H and - O weak bond |
properties of water | cohesion & adhesion good solvent lower density as a solid high specific heat high heat of vaporization |
water: cohesion | H bonding between H20 molecules Ex. surface tension |
adhesion | H bonding between H2O and other substances water sticks to other polar molecules Ex. capillary action, meniscus |
solvent | polarity makes H2O a good solvent |
hydrophilic | substances that have attraction to H2O polar |
hydrophobic | substances that don't have an attraction to H2O non-polar |
density of water | water is less dense as solid (ice) than as a liquid |
why is ice's density important | surface ice insulates the water below if ice sank the entire mass of water would be ice after some time |
specific heat | H2O resists changes in temperature energy is absorbed when H bonds are broken water moderates the earths temperature |
heat of vaporization | heat is added but once the temperature reaches 100 degrees Celsius the temperature will stay the same even when more heat is added |
water vs. methane | water melting point: 0 degrees celcius boiling point: 100 degrees celcius methane melting point: -182 degrees celcius boiling point: -160 degrees celcius |
ionization and pH of water | H+ splits off from H2O leaving OH H+ = -OH nuetral H+ > -OH acidic H+ < -OH basic |
buffer | a reservoir of H+ to keep the pH of a cell at 7 |
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