Reactions Flashcards
Skeleton equation
a chemical equation that shows the reactants & products of a reaction but does not include the coefficients to balance the equation
Balanced equation
an equation that has the same number of atoms on the reactants and products side
Chemical formula
a chemical formula represents the elements in a compound and the ratio of atoms of each element (H2O)
Chemical equation
represents a chemical reaction using symbols and formulas to show the reactants transforming into products
Catalysts
a substance that increases the rate of a chemical reaction by lowering the activation energy required for the reaction to occur. they are not consumed in the reaction
Bubble
a small pocket of gas that forms in a liquid often seen during a chemical reaction that produces gas
Indicator
a substance that changes colour or properties in response to a change in conditions such as pH
Boil
the process of heating a liquid to its boiling point, resulting in a phase change from liquid to gas
Precipitate
a solid that forms as a result of a reaction, typically when two solutions react & produce an insoluable compound
Insoluable
a substance that cannot dissolve in a solvent
Endothermic
-the system absorbs energy from its surrondings
-the overall energy of the products is higher than that of the reactants
-if energy is being used it is a reactant
Exothermic
-the system releases energy to its surrondings (transfers heat to its surrondings)
-the overall energy of the products is lower than that of the reactants
Spontaneous energy
reactions that proceed immediately when two substances are mixed (no effort)
- can happen naturally under given conditions (temp/pressure)
- e.g., rusting of iron & melting of ice at room temp.
Example of a catalyst
Manganese dioxide is a solid catalyst that accelerates the decomposition of hydrogen peroxide.
when it is added, it lowers the activation energy, meaning more hydrogen peroxide molecules can break down into water and oxygen gas at a faster rate
Ways to tell a chemical reaction has occurred
Colour change
energy change (endothermic/exothermic)
gas formation
Irreversible
precipitate is formed
Exothermic example
any reaction in which the product includes __ + E
Endothermic example
any reaction in which the reactant include E + ___
Synthesis reactions
occurs when two substances (elements) combine and form a compound
Decomposition
occurs when a compound breaks up into elements or a few simpler compounds
Combustion reactions
occurs when a hydrocarbon reacts with oxygen gas
- products are carbon dioxide and water
What do you need in order to burn something
Fuel
oxygen
ignition
Acid
nonmetallic oxide + water
Nitrates
nitrite + oxygen
Bicarbonates
carbonate + carbon dioxide + water
Hydrates
salt + water
Hydroxide
oxide + water
Chlorates
chloride + oxygen
To test for CO2
- reacts w/ limewater to form a precipitate of calcium carbonate
To test for O2
light a wooden splint and blow it out
if oxygen is present, the splint will relight
To test for H2
light a wooden splint
since hydrogen is explosive a pop sound will be produced
Double displacement
reaction where two compounds exchange ions or elements to form to two new compounds
Common characteristics of double displacement reactions
formation of parcipitate
formation of gas
formation of water
Single displacement
reaction where one element displaces another element from a compound
