Reactions in Aqueous Solutions

solvent

the substance present in the greatest quantity

solute

are the substance(s) dissolved in the solvent

aqueous solution

solution in which water is the solvent

what do ionic compounds do when they dissolve in water

they ionize or form ions

ionic compounds dissolving in detail

each ion dissociates from the solid structure and disperses throughout the solution

anions are attracted to the partial positive end of water

cations are attracted to the partial negative end of water

solvated

when ions are completely surrounded by solvent molecules to prevent them from recombining and to allow them to disperse uniformly throughout the solution

what happens to most molecular compounds when dissolved in water

the solution consists of intact molecules dispersed throughout

ex: some molecular compounds, such as acids, dissolve in water by ionizing

precipitation reactions

result in the formation of an insoluble product

follow the pattern of exchange reaction

what is the insoluble product called

precipitate

solubility

amount of substance that can be dissolved in a given quantity of solvent at the given temperature

how to write molecular equation for dummies

1. Use the chemicals formulas of the given reactants to determine which ions are present.

2. Write the chemical formulas of the products by combining the cation from one reactant with the anion from the other (following the basic form of an exchange reaction).

3. Check the water solubility of the products and give the states of the products.

4. Balance the equation.

important notes about molecular equations

1. This equation only contains compounds; not ions!

2. A precipitate must form for a reaction to occur!

how to write complete ionic equation for dummies

1. Start with a balanced molecular equation.

2. Show water soluble ionic compounds (strong electrolytes) as separate ions.

3. Distribute coefficients and physical states.

[ex. 2 KI(aq) becomes 2 K+(aq) + 2 I-(aq)]

4.Convert subscripts to coefficients EXCEPT those of polyatomic ions!

[ex. Pb(NO3)2 (aq) becomes Pb2+(aq) + 2 NO3-(aq)]

what does not separate into ions in complete ionic equations

the precipitate does not separate into ions (remains a compound)

how to write net ionic equation

1. Take complete ionic equation.

2. Remove spectator ions from both sides.

um, what are spectator ions

things that appear in identical forms on both sides of the equation and play no direct role in the reaction

important notes about net ionic equations

1. This equation only shows ions and compounds directly involved in the reaction (formation of a precipitate).

2. If every ion in a complete ionic equation is a spectator, no reaction occurs!!!!!!

ionic hydroxide compounds

dissociate into ions

ex: KOH (aq) → K⁺(aq) + OH⁻(aq)

bases that do not contain OH-

accept H⁺ ions

proton acceptors

ex. NH₃(aq) + H₂O(l) ↔ NH₄⁺(aq) + OH⁻ (aq)

substances that are insoluble in water cannot be

electrolytes