Chemical Reactions
What are indications that a chemical reaction has occurred?
-Evolution of energy as heat and light -production of a gas -formation of a precipitate(solid) -color change
What is some of the quantitative information revealed by a chemical equation?
-The coefficients indicate relative amounts of reactants and products -the relative masses of the reactants and products can be determined from the reactions coefficients -the reverse reaction has the same relative amounts of substances as the forward reaction
What is this law: The total mass of reactants must equal the total mass of products for any given chemical reaction.
Law of conservation of mass
What are the characteristics of a chemical equation?
The equation must: -represent known facts -contain the correct formulas for the reactants and products -satisfy the Law of Conservation of Mass
what does this symbol mean: (l)
a reactant or product in the gaseous state
what does this symbol mean: (s)
a reactant or product in the solid state -also used to show a precipitate
what does this symbol mean: (g)
a reactant or products in the gaseous state
what does this symbol mean: (aq)
a reactant product in an aqueous solution (dissolved in water)
the ability of an element to react
activity
a series of elements that have similar properties and that are arranged in descending order of chemical activity
activity series
a representation of a chemical reaction that uses symbols to show the relationship between the reactants and the products
chemical equation
the process by which one or more substances are changed into one or more different substances
chemical reaction
a small whole number that appears as a factor in front of a formula in a chemical equation
coefficient
when a substance combines with oxygen, releasing a large amount of energy in the form of light and heat
combustion
a reaction in which a single compound breaks down to form two or more simpler substances
decomposition
the separating of a molecule into simpler molecules, atoms, radicals, or ions
dissociation
when ions of two compounds exchange places in an aqueous solution to form two new compounds
double-replacement
the process in which an electric current is used to produce a chemical reaction, such as the decomposition of water
electrolysis
a representation of the reactants and products of a chemical reaction by their symbols or formulas
formula equation
what does this symbol mean: Mn02 ---------->
formula of catalyst, in this case manganese dioxide, used to alter the rate of the reaction
When can reactions be speeded up and take place at lower temperatures?
in the presence of a catalyst
the process of adding or removing electrons from an atom or molecule, which gives the atom or molecule a net charge
ionization
What does the Greek capital Delta mean?
means that the reactants must be heated
an equation that includes only those compounds and ions that undergo a chemical change in a reaction in an aqueous solution
net ionic equation
a solid that is produced as a result of a chemical reaction in solution
precipitate
what does this symbol mean: pressure ------------->
pressure at which reaction is carried out exceeds normal atmospheric pressure
what does this symbol mean: 2 atm --------->
pressure at which reaction is carried out, in this case 2 atm
In a chemical reaction, what are the resulting substances known as?
products
Complete the sentence: A word equation has only __________ meaning
qualitative
in a chemical reaction, what are the original substances known as?
reactants
what does this symbol mean: heat ------>
reactants are heated
a chemical reaction in which the products re-form the original reactants
reversible reaction
what does this symbol mean: -----> <----
reversible reaction
a reaction in which one element or radical takes the place of another element or radical in a compound
single-displacement
ions that are present in a solution in which a reaction is taking place but that do not participate in the reaction
spectator ions
What does a chemical equation use to represent itself?
symbols and formulas
a reaction in which two or more substances combine to form a new compound
synthesis
what does this symbol mean: 0^C ---------->
temperature at which reaction is carried out, in this case 0^C
what does this symbol mean:*up arrow* ^ |
used only to show a gaseous product
what does this symbol mean: *downward arrow*
used only to show a precipitate
How do you know when a chemical equation has No Reaction?
when all the products and reactants are aqueous
When does a precipitate form?
when the cations of one reactants combine with the anions of another reactant to form an insoluble compound
an equation in which the reactants and products in a chemical reaction are represented by words
word equation
what does this symbol mean: ---->
yields
