Chem Review Flashcards
A Trace Element
required only in minute amounts by living organisms
Elements cannot?
be broken down to other substances by chemical reactions
What is mass number?
the amount of protons + nuetrons
What is atomic number?
number of protons
What are electron shells?
The energy level of electrons at a characteristic average distance from the nucleus of an atom
What is a valence shell?
Where electrons are found in an atom during a chemical reation
whats van der Waals interaction
ability of atoms and molecules to stick together due to ever-changing regions of positive and negative charges
covalent bonds are…
sharing of electrons
How many covalent bonds can oxygen make
2
How do you know how many covalent bonds an atom can make?
By knowing how far away they are from a noble gas
What charge is Hydrogen
positive
What is cohesion
Hydrogen bonds can hold the atoms of a substance together
What is heat?
A measure of matter’s total kinetic energy due to motion of its molecules
What is a Calorie
the amount of heat required to raise the temperature of 1 g of water by 1 degree C
What is Evaporative Cooling
the “hottest” molecules, or the ones with the most kinetic energy, are leaving the surface as a gas.
What is heat of vaporization
The amount of heat 1 gram of a liquid must absorb to become a gas is known as
What does a solvent do
it dissolves things
What does a solute do
it gets dissolved
Whats a hydration shell
When a substance such as salt is dissolved in water, the ions will separate and become surrounded by water molecules
Whats a colliod
when substances that are too large to dissolve in water will remain suspended in the water
Whats the name of OH-
hydroxide ion
Whats the nanme of H3O+
hydronium ion
Whats a buffer?
A substance that minimizes changes in the concentration of hydrogen ions and hydroxide ions in a solution
What determines the cohesiveness of water moloecules?
hydrogen bonds
In a molecule of water, the oxygen atom does not share electrons equally with the two hydrogen atoms. This results in
Polar covalent bonding
Why are we able to sweat
The absorption of heat by the breaking of hydrogen bonds
What are isomers?
Molecules with the same chemical formula that have differences in covalent arrangement of atoms
what are structural isomers?
Two organic molecules with the same numbers of atoms of the same elements but different structures
What are enantiomers
Isomers that are mirror images of each other
What is a hydroxyl group?
-OH
What is a carbonyl group?
carbon double bonded to oxygen
What is a carboxyl group?
carbon bonded to OH and double bonded to O
What is an amino group?
NH2
What is a methyl group?
carbon bonded to 3 H
Which property of the carbon atom gives it compatibility with a greater number of different elements than any other type of atom?
carbon has valence of 4
What type(s) of bond(s) does carbon have a tendency to form?
covalent bonds
Amino acids are always acids because they possess which functional group?
Carboxyl
explain ocean acidification
When atmospheric CO2 dissolves in seawater, it reacts with water to form carbonic acid
explain acid precipitation
As fossil fuels are burned, it causes sulfur oxides and nitrogen oxides to be released in the atmosphere. These compounds react with water vapor to form strong acids that can then condense and fall to Earth
