2.2 Properties of Water Flashcards
Why is water a polar molecule?
- The oxygen nucleus attracts electrons more strongly than the hydrogen nucleus (electrons go around oxygen more that hydrogen)
- This causes electrons to be closer to the oxygen nucleus, creating a partial negative charge near the oxygen atom and a positive charge between the hydrogen atoms
What is a hydrogen bond?
The attraction between a hydrogen atom with a partial positive charge and another atoms with a partial negative charge
What leads to oxygen’s speacial properites?
Its polarity leads it to form multiple hydrgen bonds with other water molecules
What are water’s special properites?
Univeral Solvent, Cohesion and Adhesion, Changes in density, high surface tension, and high heat capacity
What is cohesion?
the attraction between molecules of the smae substance
What creates water’s surface tension?
Hydrogen bonds make water very cohesive and causes water molecules to be drawn to together in drops on smooth surfaces
What is adhesion?
the attraction between molecullles of different substances
Adhesion in water causes:
the surface of water in a cylinder to dip slightly in the middle bedcuase adhesion between water and the glass is stronger that the cohesion between water molecules
(also leads to capillary action)
What is a mixture?
a material composed of 2 or more elements or compounds that re physically mixed together but not chemically combined
ex: salt and sand mixed
what is a solution?
all compounds are evely distributed
what is the solute
the substance that is dissolved
what is the solvent
the substance in which the solute dissoves (water)
what is a suspension?
materials that don’t dissolve when placed in water but separate into pieces so small that they do not settle out
what is pH scale?
measurment system to indicate the concentration of hydrogen ions in a solution
What is an Acid
any compound that forms H+ ions in a solution
What is a base?
a compound that produces hydroxide ions (OH-) is solutions
What is a buffer?
a weak acid or base that can react with strong acids or bases to prevent sharp, sudden changes in pH
Why are buffers important?
to maintain homostasis in organisims
Hydrogen bonds are:
very weak
Water is a polar molecule so it forms many:
hydrogen bonds
What are common partially negative atoms involved in hydrogen bonding?
oxygen, nitrogen, and flourine
How does hydrogen bonding work between water molecules?
The slightly postive ends of a water molecule attract the slightly negative end of another water molecule
What is the specific heat of water?
4,184 joules of energy are required to raise 1 kg of water 1 degree celsius
Why is it important for water to have a high specific heat?
Water is 60-70% of the body so it is resistant to ectreme temperature changes, helps to maintain homeostasis
Living things are composed of what 2 mixtures?
Solutions and suspensions
How does salt dissolve in warn water creating a solution?
The Na+ ions bond with the negative ends of water’s polar molecule, the Cl- ions relate to the positive end
What pH scale is water, lemon juice, and bleach?
Water- neutral
Lemon Juice- acid
Bleach- base
How does milk of magnisia help with an acidic stomach?
it is a base to it neturalizes the acid
