The difference between atomic number and mass number.
Atomic number is the number of protons in the nucleus. Mass number is the number of protons + neutrons of the most common isotope.
100
substances held together by covalent bonds are called _____
molecules.
100
Define cohesion and adhesion.
Cohesion - binding between like molecules. Adhesion - bonding between unlike molecules.
200
What is Thermal/Kinetic Energy is measured in?
Temperature
200
The number of moles per liter.
What is molarity.
200
The bond when electrons are shared
Covalent
200
Why does ice float?
Water expands as it changes from a liquid to a solid.
200
What kind of bond occurs when electrons are asymmetrically shared?
Polar covalent bond.
300
What is heat?
The thermal energy transferred between objects of different temperatures.
300
How do you find the molecular weight of a molecule?
The sum of the mass numbers of all the atoms in the molecule.
300
Bond when electrons are transferred from one atom to another.
Ionic
300
Ions and polar molecules stay in solution because of their interactions with waters partial charges. These atoms and molecules are said to be:
hydrophilic
300
The five major functional groups found in organic molecules.
What is amino and carboxyl groups, carbonyl groups, hydroxyl groups, phosphate groups, and sulfhydryl groups.
400
What is entropy?
The amount of disorder in a group of molecules.
400
what are buffers?
compounds that minimize changes in pH
400
What is a nonpolar covalent bond?
When electrons are evenly shared between two atoms and the bond is symmetrical.
400
what is the pH of pure water?
7.
**acids have a pH of less than 7 and bases have a pH of greater than 7
400
Two times chemical reactions occur.
1. When one substance is combined with another. 2 One substance is broken down into another substance.
500
What are the first and second laws of thermodynamics?
First law states that energy is conserved- it cannot be created or destroyed, but it can be transferred or transformed. Second law states tat energy always increases..chemical reactions result in products with less ordered (usable) energy.
500
How do two isotopes of an element compare and differ.
Same atomic number and same chemical reactions. They differ by the amount of neutrons.
500
An attraction between oppositely charged ions.
Ionic Bond
500
In ice, water molecules form:
a crystal lattice
500
The difference between molecular formulas and structural formulas.
Molecular formulas indicate the numbers and types of atoms in a molecule (H2O) Structural formulas indicate which atoms are bonded together and whether the bonds are single, double or triple bonds.