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chemistry exam

Terms in this set (34)

ion
atoms or groups of atoms that have a positive or negative charge
ionic compound
metal + non-metal
covalent compound
non-metal + non-metal
what is the difference between endothermic and exothermic? - provide examples of each.
endothermic: a reaction during which energy is absorbed - cake in oven
exothermic: a reaction during which energy is released - explosion
s,l,aq,g
solid, molten, aqueous, gas
what is the difference between complete combustion and incomplete combustion? - provide Bunsen burner example
complete combustion occurs when there is plentiful oxygen (such as when the bunsen burner holes are open) and when every carbon in the fuel becomes carbon dioxide so there is no residue.
incomplete combustion is when a substance burns in a limited supply of oxygen and only produces water gas and carbon solid, so produces soot (bunsen burner when holes are closed)
precipitate reactions
when two ionic solutions react together and swap partners, a solution and a precipitate will be formed
what is the difference between cation and anion?
a negatively charged ion is a antion
a positively charged ion is an cation
how is aqueous different from molten?
aqueous: dissolved in water/melted in water - can conduct electricity as the ions are free to move (AQ)
molten: when a solid turns to liquid - can conduct electricity as the ions are free to move (L)
crystal
Millions of sodium ions, each attract the opposite charged ion which makes up a crystal lattice (positive and negative charges balance each other out).
conductor of electricity
all ionic compounds conduct electricity when dissolved in water, as the ions are free to move around.
compound ion (radical)
a group of atoms together have lost or gained electrons. this is evident because it will have more than 1 capital letter.
precipitate
the solid that forms when two ionic solutions react together and swap partners
snap ion
sodium, potassium, nitrate and ammonium ions - when they are present in a compound, it will always be soluble
slb ion
silver, lead, barium - when these are present the substance will be solid except if they are with snap ions, in which case they will be soluble
co-efficient
large numbers placed out out the front of a formula in an equation that are used to balance it.
variable valency ion
metals form the transition block, which can have different charges for their valency. the charge is indicated by roman numerals; iron (III) = Fe ^3+
carbon monoxide poisoning
occurs when the carbon monoxide gas binds with the hemoglobin in the red blood cell preventing oxygen from being carried around, leading to oxygen deprivation - highly toxic.
electron shell structure diagram for the formation of positive ions; magnesium
...
electron shell structure diagram for the formation of negative ions; chloride
...
what is a stable electron configuration of a full outer shell?
a stable electron configuration has a full outer shell. if its the first shell then it requires 2 electrons, any more than the first shell requires 8 electrons.
why do noble gases in group VIII not react to form ions?
noble gases do not react to form ions because they already have full outer shells.
how can you tell the difference between ionic compounds and covalent compounds by observing the formula?
covalent compounds will have 2 metals reacting, whereas ionic compunds will have 1 metal and 1 non-metal reacting.
what is a covalent bond? how is it different from an ionic bond?
covalent is the chemical bonds produced from the sharing of electrons by at least 2 atoms. ionic bonds are the chemical bonds caused by attraction between oppositely charged ions
what is the difference between polar covalent bonds and non-polar covalent bonds?
polar covalent bonds are unequal sharing of electrons, non polar covalent bonds are equal shared electrons
what do covalent bonds not conduct electricity?
their molecules do not form ions so it cant produce an electric current.
what is a metallic bond? why can it conduct electricity?
inside any metal are numerous positively charged ions which create the sea of electrons. because they are freely moving they are able to carry electric currents
what are the major properties of ionic compounds? (crystalline nature, melting point, solubility, ability to conduct)
- compounds made up of ions held together by ionic bonds.
- wont conduct electricity in solid state because the ions are locked in a crystal lattice
- high melting points due to strong bonds in many directions
- can conduct when melted
what is the difference between atoms, ions, and compound ions?
atoms: atoms are the building blocks of all matter - no charge
ions: atoms or groups of atoms that have a positive or negative charge
compound ions: ions consisting of groups of atoms
when do you need to use brackets in an ionic formula?
to indicate that the compound ion acts as a single unit
explain the use of roman numerals in brackets in formulas
show the charge of a metal ion when an element can form different charges
give word equation and symbolic equation:
pentane gas (C5H12) is burnt in plentiful supply of oxygen
C5H12 + O = O + CO2
what are the products of and the state of fuel burnt in complete or incomplete combustion
complete: oxygen and carbon dioxide (g)
incomplete: cabon dioxide (s) and carbon monoxide
precipitation reactions;
10 drops of potassium iodine solution is reacted with 10 drops of lead nitrate solution and a bright yellow solid is formed.
potassium iodine (aq) + lead nitrate (aq) = potassium nitrate (aq) + lead iodine (s)

2Kl (aq) + Pb(N0>3)>2 (aq) = 2KNO>3 (aq) + Pbl>2 (s)
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