Chemical Formulas
* Chemical Formulas and Reactions
. . . Midterm
Objectives: * To balance chemical equations. * To interpret chemical reactions. * To understand equilibrium reactions and the factors that can affect them.
* Molecular Mass / Formula Mass * Is the sum of the atomic masses of all the atoms present in one molecule of that compound.
Example: the molecular mass of sodium bromide, NaBr, is 103, which represents the sum of the atomic mass of sodium (23) plus that of bromide (80).
* Calculating the Molecular Mass (Formula Mass) of a Compound * To find the molecular mass of a compound, add the atomic masses of all the atoms that are present in that compound. * In the compound H2O, the molecular mass can be calculated by adding the mass of two atoms of hydrogen and one atom of oxygen.
* Calculating the Molecular Mass (Formula Mass) of a Compound
2 hydrogen atoms (atomic mass – 1) 2 * 1 = 2
1 oxygen atom (atomic mass – 16) 1 * 16 = 16 Molecular mass = 18
* Calculating the Molecular Mass (Formula Mass) of a Compound * The molecular mass of glucose, C6H12O6, can be calculated as follows:
6 carbon atoms (atomic mass – 12) 6 * 12 = 72
12 hydrogen atoms (atomic mass - 1 ) 12 * 1 = 12
6 oxygen atoms (atomic mass – 16) 6 * 16 = 96 Molecular Mass = 180 * Calculating the Molecular Mass (Formula Mass) of a Compound * The molecular mass of calcium phosphate, Ca3(PO4)2, can be calculated as follows:
3 calcium atoms (atomic mass – 40) 3 * 40= 120
2 phosphorus atoms (atomic mass – 31) 2*31 = 62
8 oxygen atoms (atomic mass – 16) 8 * 16 = 128 Molecular Mass = 310
* Percentage Composition * The percentage composition of a compound can be calculated from the relative atomic masses of the elements present in that compound. * Consider the compound Ca3(PO4)2, calcium phosphate, whose molecular mass was found to be 310. * Of this mass, 120 is
. . . Midterm
Objectives: * To balance chemical equations. * To interpret chemical reactions. * To understand equilibrium reactions and the factors that can affect them.
* Molecular Mass / Formula Mass * Is the sum of the atomic masses of all the atoms present in one molecule of that compound.
Example: the molecular mass of sodium bromide, NaBr, is 103, which represents the sum of the atomic mass of sodium (23) plus that of bromide (80).
* Calculating the Molecular Mass (Formula Mass) of a Compound * To find the molecular mass of a compound, add the atomic masses of all the atoms that are present in that compound. * In the compound H2O, the molecular mass can be calculated by adding the mass of two atoms of hydrogen and one atom of oxygen.
* Calculating the Molecular Mass (Formula Mass) of a Compound
2 hydrogen atoms (atomic mass – 1) 2 * 1 = 2
1 oxygen atom (atomic mass – 16) 1 * 16 = 16 Molecular mass = 18
* Calculating the Molecular Mass (Formula Mass) of a Compound * The molecular mass of glucose, C6H12O6, can be calculated as follows:
6 carbon atoms (atomic mass – 12) 6 * 12 = 72
12 hydrogen atoms (atomic mass - 1 ) 12 * 1 = 12
6 oxygen atoms (atomic mass – 16) 6 * 16 = 96 Molecular Mass = 180 * Calculating the Molecular Mass (Formula Mass) of a Compound * The molecular mass of calcium phosphate, Ca3(PO4)2, can be calculated as follows:
3 calcium atoms (atomic mass – 40) 3 * 40= 120
2 phosphorus atoms (atomic mass – 31) 2*31 = 62
8 oxygen atoms (atomic mass – 16) 8 * 16 = 128 Molecular Mass = 310
* Percentage Composition * The percentage composition of a compound can be calculated from the relative atomic masses of the elements present in that compound. * Consider the compound Ca3(PO4)2, calcium phosphate, whose molecular mass was found to be 310. * Of this mass, 120 is