water Flashcards
Majority of human body constituted of
Oxygen
Carbon
Hydrogen
Nitrogen
Importance Ions Bio
Movement Ca2+, Na+, K+ causes nerve impulses
role of Ca2+ ions in muscle contractions
Hydrogen bonds
Hydrogen atom is covalently bonded to an electronegarive atom (oxygen, nitrogen, fluorine, sometimes sulhpur) that have at least 1 lone pair, and is attracted to another electronegative atom
Not a bon, but so relevant in high quantity that we clal it so.
Causes dipole moment, which are main factor that determines physical properties (ex Boiling point, double strand of DNA). More hydrogen bonds means more energy needed to seperate molecule from others
represented by dotted lines
hydrolysis and dehydration synthesis reactions
hydrolysis: to hydrate to seperate
dehydration synthesis: dehydrate to synthesis
Important properties and roles of water
solvent
cohesion, adhesion, tension
moderatuon of temperature
acids, bases, pH
Solvent water
water can disolves polar and ionic (hydrophilic) solutes. nonpolar (hydrophobic) dont dissolve well
Not all hydrophilic substances dissolve in water ex:glass
hydration
water molecules surround solute, with negaite charge attaching to positve charge of cations of solute, and vice versa
cohesion
hydrogen bonds holding together the water
contributes to transport of water agaisnt gravity in plants (as water evaporates, water molecule leaving the leaf will pull the others down and transport it up)
adhesion
forces between particle and others of a different kind (ex water and glass causes minuscus)
helps water go up plant as the adhesion to the walls of the cells helps counter the dounward pull
Capillary action
result of adhesion and surface tension. surface tension acts to hold surface intact, and adhesion rases the edges up, so surface tension will pull it all up and it will travel upwad a lot
the thinner the tube, the higher it goes as less mass and less gravity is acting on the water
Surface tension
measure of how difficult is it to stretch or break the surface of a liquid.
molecule sat the surface exhibit stronger attraction to their neighbors than molecules down in the liquid, as the do not have molecules above them
energy state pf the molecules inside liquid is lower that surface, so liquid tries to maintain minimum surface area
acts to hold surface intact, makes it take a shape
in lungs, while premature birth, alveoli (small sacs) are coated with a thin film of water, surface tension can prevent them from expanding for breath, causing RDS. Specialised cells secreate pulmonary surfactant, which decrease ssurface tension and breaks the bonds between water molecules
Heat
total quatity of kinetic energy due to molecular motion, energy that can be trasnferred between objects of different temperature
greater the mass, greater the heat
temperature
measure of the intensity of heat
specific heat
amount of heat needed for 1 g of that substance to change by 1*C
Water has high specific heat because of its hydrogen bonds, much of the heat transferred is used to disrupt hydrogen bonds
large bodies of water can absorb lots of heat and the cooling during night/winter can gradually warm the air around
as organisms made of water, our bodies resist change in their own temperature easiest (ex kill bacteria)
heat of vaporization
Amount of heat required to convert 1 unit of mass of a liquid into vapor
