Basic Chemistry
What are covalent bonds?
Covalent bonds occur when two or more atoms share electrons. This is the strongest bond that can occur and does NOT result in an overall charge on the atoms involved.
List the 6 most common elements in life
1. Carbon!!!!! 2. Hydrogen 3. Nitrogen 4. Oxygen 5. Phosphorus 6. Sulfur
After the reaction occurs, how many elements are there? 2H2 + O2 --> 2H2O
2 - Hydrogen and Oxygen
Before the reaction occurs, how many elements are there? 2H2 + O2 --> 2H2O
2 - Hydrogen and Oxygen
After the reaction occurs, how MANY TOTAL molecules are there? 2H2 + O2 --> 2H2O
2 molecules of water
Before the reaction occurs, how MANY TOTAL molecules are there? 2H2 + O2 --> 2H2O
3 - 2 molecules of H2 and 1 molecule of O2
How many TYPES of molecules are there in the reaction above? 2H2 + O2 --> 2H2O
3 - H2 , O2, and H2O
Before the reaction occurs, how many TOTAL atoms are there? 2H2 + O2 --> 2H2O
6 - 4 total atoms of hydrogen and 2 total atoms of oxygen
After the reaction occurs, how many TOTAL atoms are there? 2H2 + O2 --> 2H2O
6- - 4 total atoms of hydrogen and 2 total atoms of oxygen
What is a chemical reaction?
A chemical reaction is any situation in which some bonds form or break between atoms. The atoms or molecules involved in the reaction are called REACTANTS and the molecules or ions produced AFTER the reaction are called PRODUCTS
If you compare the structure of a hydrogen ion to the structure of a regular hydrogen atom, what is the difference in subatomic parts?
A hydrogen ion will have gained or lost an electron. A hydrogen atom will have one proton. If it is a positive ion (what you typically see for hydrogen) it has lost an electron and therefore has one positive proton and NO electrons. If it has a negative charge, it has gained an electron so it would have one proton and two electrons.
When atoms are joined what is formed?
A molecule (or compound) is formed. Energy goes into the creation of the bond and in dehydration synthesis a water molecule forms and leaves.
What is a molecule?
A molecule is a group (2+) of atoms that have been bonded together. Side note: Technically speaking a molecule has to be covalently bonded. A compound includes any two different molecules that are bonded together (either covalently or ionically). This is NOT a distinction that you are required to make. For our purposes, just consider compounds and molecules to both be atoms that are joined together.
What is an element?
An element is a certain TYPE of atom based on the number of protons it contains. All hydrogen atoms, for example, contain 1 proton.
Where does energy go?
Energy goes INTO the bond that is created. When the bond eventually breaks the energy is released. This energy never transfers perfectly and in every reaction some of the energy is always lost as heat.
What are ionic bonds?
Ionic bonds occur when one atoms takes an electron from another atom. This results in ions (charged particles). The atom that takes the extra electron becomes negative while the atom that loses the electron becomes positive. The two atoms generally stay next to each other because opposite charges attract. This type of compound is considered hydrophilic (it mixes with water).
Describe in words the chemical equation below 2H2 + O2 --> 2H2O
Two molecules of hydrogen gas (two hydrogens bonded together) are combined with one molecule of oxygen gas (two oxygen atoms bonded together) in order to form two molecules of water (two hydrogen atoms bonded to one oxygen atom).
How are polar covalent bonds different from nonpolar covalent bonds?
When atoms share electrons, they can either share them equally or unequally. If it is a polar covalent bond, the electrons are shared UNEQUALLY. One of the atoms will hold the electron closer and at times can get a slight charge. Water is an example of a polar covalent bond. Nonpolar covalent bonds share the electrons completely equally and, therefore, never receive even a slight charge. Carbon- hydrogen bonds are an example of nonpolar bonds. Polar bonds are considered hydrophilic (they mix with water) while nonpolar bonds are considered hydrophobic (they do NOT mix with water).
