chemistry module 2 definitions Flashcards
(37 cards)
Relative Abundance
the amount of one substance compared to another
relative atomic mass
the weighted mean mass of an atom compared with 1/12th mass of
an atom of carbon-12.
relative isotopic mass
the weighted mean mass of an isotope in comparison with 1/12th mass of an atom of carbon 12
relative formula mass
the mass of the formula unit of a compound with a giant structure.
For example, NaCl has a relative formula mass of 58.44 g mol-1
relative molecular mass
mr
ionic compound
a compound which is made up of oppositely charged ions that are held
together by electrostatic forces.
diff ions
-sulphate
-ammonium
-carbonate
-hydroxide
-nitrate
-silver
-zinc
-so4 2-
-nh4 +
-co3 2-
-oh -
-no3 2-
-ag +
-zn 2+
state symbols
symbols within a chemical equation which indicate the state of each
compound under the reaction conditions. (g) gaseous, (l) liquid, (s) solid and (aq) aqueous
amount of substance
the quantity that has moles as its units, used as a way of counting
atoms. The amount of substance can be calculated using mass (n = m/M), gas volumes (n =
pV/(RT)) or solution volume and concentration (n = CV)
anhydrous
a crystalline compound containing no water.
atom economy
a measure of the amount of starting materials that end up as useful
products. A high atom economy means a process is more sustainable as there is less waste
produced
avogadro’s constant
the number of particles per mole of substance (6.02 x 1023 mol-1).
composition by mass
the relative mass of each element in a compound
hydrated
a crystalline compound that contains water
ideal gas
a gas which has molecules that occupy negligible space with no interactions
between them. The ideal gas equation is: pV = nRT
stoichiometry
the relative quantities of substances in a reaction
water of crystallisation
water molecules that form part of the crystalline structure of a
compound.
acid
compounds that release H+
ions in aqueous solution. Common acids include: HCl,
H2SO4
, HNO3
and CH3COOH
alkali
water soluble bases. Alkalis release OH-
ions into aqueous solution. Common alkalis
include: NaOH, KOH and NH3
bases
accept H+ ions but do not have to be water soluble, the ones that are are called alkalis
neutralisation
a reaction between H+
and OH-
, forming water. This may be a reaction
between an acid and a base to form a salt (types of bases include carbonates, metal oxides
and alkalis)
strong acid
an acid that completely dissolves in solution
titration
a technique used to determine the amount of one solution of a known
concentration required to completely react with a known volume of another solution of
unknown concentration.
weak acid
an acid that only partially dissociates in solution
