Chemical Formulas

At the end of the day you will be able to: Identify elements in a formula Determine how many of each element are present.

Atom – Basic building block of all matter. Chemical Symbol – A symbol for each atom. If just one letter, it is capitalized. If it is two letters only the first letter is capitalized.

How many elements? NaCl is made up of ___ elements

How many elements? NHCR is made up of ____elements

How many elements? BaMnO is made up of ___elements

How many elements? MgSO is made up of __ elements

Deciphering a Chemical Formula Molecule – Two or more atoms combined. Table Salt = Sodium Chloride = NaCl

Subscript Number – In a chemical formula it tells you how many of a particular atom is in the molecule. If it is greater then 1, it is after the chemical symbol and slightly lower. If it is 1, nothing is written, it is assumed. Water = H 2 O Hydrogen = 2 atoms Oxygen = 1 atom One Molecule of water has 3 atoms

Coefficient- This is a number in front of a chemical formula. It indicates that you have multiples of the molecule behind it. 2 H 2 O 4 Hydrogen 2 Oxygen 6 Atoms Total

Special Cases Multiply the subscripts first then multiply with the coefficient if there is one. Fe 2 (O 2 ) 2 = 2 Fe 4 Oxygen = 6 atoms total

Special Cases Multiply the subscripts first then multiply with the coefficient if there is one. For Oxygen 2 x 2 x 2 = 8 2 Fe 2 (O 2 ) 2 = 4 Fe 8 Oxygen = 12 atoms total

How many Atoms? Hydrogen Peroxide = H 2 0 2

2 Hydrogen 2 Oxygen 4 Total

How many Atoms? 2H 2 O 2 =

How many Atoms? 2H 2 O 2 4 Hydrogen 4 Oxygen 8 Total

How many Atoms? H 2 (O 2 ) 2 =

How many Atoms? H 2 (O 2 ) 2 = 2 Hydrogen 4 Oxygen

How many Atoms? 2H 2 (O 2 ) 2 =

How many Atoms? 2H 2 (O 2 ) 2 = 4 Hydrogen 8 Oxygen 12 Total

Figure out the number of Atoms of each Element in the Following: 1.CO 2 = _____________________________ 2.C 6 H 12 (O 3 ) 2 = ________________________ 3.2Ca(O 2 ) 2 = _________________________ Bring your completed sheet to the front to be checked and get the assignment.

Chemical Equations Chemistry in Biology  Chemical formulas describe the substances in the reaction and arrows indicate the process of change.  Reactants are the starting substances, on the left side of the arrow.  Products are the substances formed during the reaction, on the right side of the arrow. 6.2 Chemical Reactions Chapter 6

 Carbon Dioxide and Water react with sun light to form glucose and oxygen. Chemistry in Biology 6.2 Chemical Reactions Chapter 6

Chemistry in Biology Balanced Equations  The law of conservation of mass states matter cannot be created or destroyed.  The number of atoms of each element on the reactant side must equal the number of atoms of the same element on the product side. 6.2 Chemical Reactions Chapter 6

On a small sheet of paper do the following. 1. Write out the formula for photosynthesis 2.Above each part of the formula label the reactant side and product side 3.List the types of atoms on each side 4.Count how many of each type of atom are present on each side. 5.Turn in without your name.