Chemical Formulas Knowledge is the product of reactant thoughts…

Words, words, words…is that all we can say? How can we name compounds made from different elements? How can we name compounds made from different elements? How can we create a shorthand way to indicate each compound using its symbols and use it to show how a chemical change occurs? How can we create a shorthand way to indicate each compound using its symbols and use it to show how a chemical change occurs? Answer: Chemical formulas and Chemical equations… Answer: Chemical formulas and Chemical equations…

Why Johnny was not a chemist… Johnny drank some water, Johnny drank some water, But Johnny drinks no more, But Johnny drinks no more, For what Johnny thought was H 2 O, For what Johnny thought was H 2 O, Was H 2 SO 4 Was H 2 SO 4 LEARN TO READ CHEMICAL FORMULAS! LEARN TO READ CHEMICAL FORMULAS! DON’T end up like Johnny. DON’T end up like Johnny.

What is a chemical formula? A chemical formula is a combination of chemical symbols and numbers to represent a substance. A chemical formula is a combination of chemical symbols and numbers to represent a substance. Example: Example: The H has a subscript, a number written below and to the right of a chemical symbol in a formula, to indicate that there are two Hydrogen atoms in this compound.

Prefixes used in chemical names: Mono- 1 Hexa- 6 Di- 2 Hepta- 7 Tri- 3 Octa- 8 Tetra- 4 Nona- 9 Penta- 5 Deca- 10

Chemical Equations A chemical equation is a representation of a chemical reaction that uses symbols to show the relationship between the reactants and the products. A chemical equation is a representation of a chemical reaction that uses symbols to show the relationship between the reactants and the products. A reactant is a substance that participates in the chemical reaction A reactant is a substance that participates in the chemical reaction A product is a substance that is formed through the change in the chemical reaction. A product is a substance that is formed through the change in the chemical reaction.

Does it all add up? A chemical equation (meaning equal) represents the actual changes occurring in the atoms and molecules, and therefore must have equal amounts of each atom on each side of the arrow. A chemical equation (meaning equal) represents the actual changes occurring in the atoms and molecules, and therefore must have equal amounts of each atom on each side of the arrow. To insure that equations are correct, one must balance a chemical equation to insure that it accurately describes the chemical reaction. No atoms may be created spontaneously or destroyed/lost due to the Law of Conservation of Mass. To insure that equations are correct, one must balance a chemical equation to insure that it accurately describes the chemical reaction. No atoms may be created spontaneously or destroyed/lost due to the Law of Conservation of Mass.

The Law of Conservation of Mass This law states that matter can not be created or destroyed in ordinary chemical and physical changes. This law states that matter can not be created or destroyed in ordinary chemical and physical changes. In layman’s terms: everything comes from somewhere, and nothing can disappear without a trace… In layman’s terms: everything comes from somewhere, and nothing can disappear without a trace…

What is a coefficient? A coefficient is a number that is placed in front of a chemical symbol or formula. A coefficient is a number that is placed in front of a chemical symbol or formula. For example: 2CO, the 2 indicates two molecules of Carbon monoxide, giving a total of two carbon atoms and two oxygen atoms. For example: 2CO, the 2 indicates two molecules of Carbon monoxide, giving a total of two carbon atoms and two oxygen atoms. The coefficient indicates the number of those atoms or molecules present in the chemical reaction. Coefficients may be changed when balancing equations. However the subscript may not be changed, because this will change the chemical identity of the substance! The coefficient indicates the number of those atoms or molecules present in the chemical reaction. Coefficients may be changed when balancing equations. However the subscript may not be changed, because this will change the chemical identity of the substance!

Balancing an Equation: An example-

Step 2:

Step 3:

Some Strategies for Balancing equations: 1. Count the atoms in both the reactants and products. 1. Count the atoms in both the reactants and products. 2. The atom that has the largest difference between reactants and products should be the first one you attempt to balance using coefficients. Increase the products appropriately by adding a coefficient and see if this works. 2. The atom that has the largest difference between reactants and products should be the first one you attempt to balance using coefficients. Increase the products appropriately by adding a coefficient and see if this works. 3. Count the atoms again, and add coefficients to the reactants if necessary. 3. Count the atoms again, and add coefficients to the reactants if necessary. 4. If the same atoms are present in two of the reactants and products, then you must find the right proportion of atoms from the products and try the reverse proportion in the reactants—it may need to be scaled up or down depending on the total number of atoms involved in the reaction. This can get frustrating, so patience is important. Keep trying common proportions. 4. If the same atoms are present in two of the reactants and products, then you must find the right proportion of atoms from the products and try the reverse proportion in the reactants—it may need to be scaled up or down depending on the total number of atoms involved in the reaction. This can get frustrating, so patience is important. Keep trying common proportions. 5. Count the atoms again, adjusting the products first, and then the reactants. 5. Count the atoms again, adjusting the products first, and then the reactants.