Review:
­ different states of matter
­ determining states of matter
Oct 22­7:57 AM
Formation (Combination) Reactions
­
a synthesis reaction (also known as a formation or combination reaction) is one in which two or more reactants combine to form a single product
General Form:
Element A + Element B Compound AB
Example:
2 Na(s)
+ Br2(l)
2NaBr(s) (Ionic Compound)
Oct 22­7:59 AM
1
NOTE: diatomic elements are written as diatomics in a reaction: Cl2, H2, O2, N2, Br2, F2, I2,
P4 and S8
NOTE: the compound formed must be correctly written using charges/crossover method if it is ionic
Steps To Writing a Correct Chemical Equation
1. List compounds with the correct formulas
2. Write the states
3. Balance using the coefficients
Oct 22­2:53 PM
Examples:
Write the formation reaction for each of the following. Be sure to write the correct formula, balance correctly, and include states.
(a) sodium metal reacts with chlorine gas
Oct 22­2:57 PM
2
(b) Hydrogen gas reacts with chlorine gas
(c) Carbon reacts with sulfur to produce solid carbon disulfide
Oct 22­3:02 PM
(d) Calcium nitride is formed from its elements
Oct 22­3:03 PM
3
Readings:
Pages 233 ­ 235
Activity:
Worksheet
Oct 22­3:03 PM
4