types of chemical reactions

Question 1

Combination reaction

Answer 1

two or more reactants forming a product

2 H2 (g) + O2 (g) —-> 2 H2O (g)

A+B —-> C

Question 2

Decomposition reaction

Answer 2

the opposite of a combination reaction
a single reactant breaks down into two or more products
usually as as a result to: heat, high frequency radiation, electrolysis, electricity

there’s usually a delta sign over the reaction representing the addition of heat

2 HgO (s) –> 2Hg (l) + O2 (g)

A —> B+C

Question 3

Combustion reaction

Answer 3

involves fuel - usually a hydrocarbon - and an oxidant (normally oxygen)
in the most common form, these reactants form two products of CO2 and H2O

CH4 + 2 O2 –> CO2 + 2 H2O

Question 4

Simple Displacement reaction

Answer 4

occurs when an atom or ion in a compound is replaced by an atom or ion in another element

ex: a solid copper metal will displace silver ions in a clear solution of silver nitrate to form a blue copper sulfate solution and solid silver metal

Cu (s) + AgNO3 (aq) —> Ag (s) + CuNO3 (aq)

this reaction is often classified as oxidation - reduction reactions

AgNO3 has an oxidation state of +1 but when it leaves the compound, it gains one electron (the Ag+ is reduced to Ag)
Copper loses an electron (oxidation) when it joins the nitrate ion.

Question 5

Double Displacement Reactions

Answer 5

also called metathesis reactions

• elements of two different compounds swap places with each other to form to new compounds
• occurs when one of the products is removed from the solution as a precipitate or gas or when two o the original species combine to form a weak electrolte that remains undedicated in solution.

CaCl2 (aq) + 2 AgNO3 (aq) —–> Ca(NO3)2 (aq) + 2 AgCl (s)

Question 6

Neutralization Reactions

Answer 6

specific type of double displacement reaction in which an acid reacts with a base to produce a salt (and usually water)

HCl (aq) + NaOH (aq) —-> NaCl (aq) + H2O (l)