Chapter 4: Types of Chemical Reactions and Solution Stoichiometry Flashcards
Define: solution
a combination of two or more substances that exist as a homogeneous mixture
Define: solvent
the substance present in the greatest quantity in a solution
Define: solute
the substance of lesser quantity in a solution
Define: solubility
a measure of the amount of substance that will dissolve in a given amount of solvent at a given temperature
Define: aqueous solution
solution in which water is the solvent
Define: concentration
amount of solute / volume of solution
Define: molarity
moles of solute/ litres of solution
Fill in the blank: when ionic solids (salts) are dissolved in polar solvents such as H2O, they _________
dissociate into anions and cations
Water can dissolve non-ionic compounds as long as?
they are polar (remember: like dissolves like)
Give some evidence for a (possible) chemical reaction (5)
– formation of a precipitate (an insoluble solid) – formation of a gas – change in colour – change in temperature – dissolution of a precipitate
Define: precipitation reactions
reactions of two soluble ionic compounds that yield an insoluble product (precipitate)
not all ionic compounds are soluble in H2O, but those that are _____________
completely dissociate
Fill in the blank: ionic solids that precipitate out of solution must be ______________
electrically neutral
List the solubility rules
- Group 1 elements are soluble
- ammonium (NH4+ ), acetate (C2H3O2-), nitrate (NO3-)
- chlorides, bromides, and iodides are soluble except with Ag+, Pb2+, Hg22+
- sulfates are soluble except with Ca2+, Sr2+, Ba2+, Pb2+
Define: molecular equation
A molecular equation is an equation in which the formulas of the compounds are written as though all substances exist as molecules.
AgNO3(aq) + KI(aq) → AgI(s) + KNO3(aq)
Define: complete ionic equation
breaking all the soluble ionic compounds (those marked with an (aq)) into their respective ions
Ag+(aq) + NO3-(aq) + K+(aq) + I -(aq) → AgI(s) + K+(aq) + NO3-(aq)
Define: net ionic equation
A net ionic equation shows only the chemical species that are involved in a reaction
Ag+(aq) + I -(aq) → AgI(s)
Define: Selective Precipitation
- process used for qualitative analysis where mixtures of ions are separated by performing a series of reactions and precipitating the ions one at a time
Define: tailing ponds
- reservoirs that are lined with plastics and concrete so water does not leech out.
- wastes from mining ends up in tailing ponds
- water is full of heavy and toxic metals
- example: arsenic sludge is poured into pond
- water slowly evaporates overtime and they can extract the arsenic out
Define: arrhenius concept
in water, acids produce hydrogen ions and bases produce hydroxide ions
What is another name for acid and base?
acid: proton donor
base: proton acceptor
What are the reactants and products of a neutralization reaction?
reactants: strong base and strong acid
products: salt and water
Describe acid-base titrations
- Use acid-base titrations to determine, for example, the amount of acid in an unknown sample
- Usually a controlled reaction of adding base (the titrant) of known concentration to the acid. The point in the titration at which enough titrant has been added to react completely with the unknown acid is called the equivalence point or stoichiometric point
- Acid base titrations require the use of an indicator. Indicator: a different color when it is in an acidic solution compared to when it is in a basic solution. commonly it is phenolphthalein
Define: Oxidation-reduction reactions (Redox reactions)
a reaction in which one or more electrons are transferred between atoms or molecules
