1.1 formulae and equations Flashcards
what is the formula of hydrochloric acid?
HCl
what salt does hydrochloric acid make?
chlorides
what is the formula of sulphuric acid?
H2SO4
what salt does sulphuric acid make?
sulphates
what is the formula of nitric acid?
HNO3
what salt does nitric acid make?
nitrates
what is the formula of ethanoic acid?
CH3CO2H
what salt does ethanoic acid make?
ethanoates
what are the 4 acid equations?
- acid + metal -> salt + hydrogen
- acid + metal oxide -> salt + water
- acid + metal hydroxide -> salt + water
- acid + metal carbonate -> salt + water + carbon dioxide
what are diatomic elements?
elements that exist in pairs e.g N2
what is the formula of carbon dioxide?
CO2
what is the formula of methane?
CH4
what is the formula of ammonia?
NH3
what is the formula of sulfur dioxide?
SO2
what is the formula of sulfur trioxide?
SO3
what is the formula of hydrogen?
H2
what is the formula of fluorine?
F2
what is the formula of chlorine?
Cl2
what is the formula of oxygen?
O2
what is the formula of nitrogen?
N2
what is the formula of ozone?
O3
what is the formula of hydrogen sulfide?
H2S
what is the formula of carbon monoxide?
CO
what are the diatomic elements?
Br2, I2, N2, Cl2, H2, O2, F2
do all group 0 elements exist as single atoms?
yes
what are the general rules of thumb when working out the charges of elements?
- group 1 = +
- group 2 = 2+
- group 3 = 3+
- group 7 = -
- group 6 = 2-
- group 5 = 3-
- a roman numeral after an element is the number of positive charges it has e.g Cu(II) = Cu 2+
what does it mean if an element ends in -ide?
the element is on its own e.g nitride
what does it mean if an element ends in -ate?
it is with oxygen e.g nitrate
what is the formula and charge of ammonium?
NH4 +
what is the formula and charge of carbonate?
CO3 2-
what is the formula and charge of hydroxide?
OH -
what is the formula and charge of nitrate?
NO3 -
what is the formula and charge of sulfate?
SO4 2-
what is the formula for copper (I) oxide?
Cu + and O 2-
==== Cu2O
what is the formula of calcium nitride?
Ca 2+ and N 3-
==== Ca3N2
what is the charge on the phosphate ion if the formula of magnesium phosphate is Mg3(PO4)2?
PO4 3-
work out the charge on X in XAl(NO3)4?
NO3 - x 4 = 4-
XAl = 4+
Al = 3+
X = X+
write a (balanced) symbol equation for the reaction between sulfuric acid and calcium carbonate
CaCO3 + H2SO4 → CaSO4 + CO2 + H2O
what are the 5 steps to make an ionic equation?
- write a full balanced equation
- dissociate (split up) soluble compounds into aqueous compounds
- write the equation after dissociating the soluble compounds
- cancel out spectator ions (both sides of reaction arrow)
- write an equation with what is left - include state symbols
what do oxidation numbers tell us?
what’s been oxidized/reduced
(it gives the oxidation state of an element or ionic substance)
(the oxidation number of an element is the number of electrons that need to be added to (or taken away from) an element to make it neutral)
what does oxidation mean?
something has lost 1 or more electrons
OIL
what does reduction mean?
something has gained 1 or more electrons
RIG
what are redox reactions?
reactions where oxidation and reduction has occurred
what are the 6 rules of oxidation numbers?
- the oxidation number of an element in its standard state (at room temperature and pressure) is 0 and an element on its own is also 0
- the oxidation no. of an element in a compound or ion is USUALLY formed from that element if it became an ion e.g Cl- has an oxidation no. of -1 (however there are exceptions)
- hydrogen is always +1 unless bonded only to a metal (in metal hydrides) where it becomes -1
- oxygen is always -2 unless in a peroxide -1 or with a fluorine +2
- the sum of all oxidation numbers equal 0 in a neutral compound or the charge on the ion if the species in question is an ion
- in chemical species with atoms of more than one element, the most electronegative element is given the negative oxidation number
when is the oxidation number of hydrogen not +1?
when it’s bonded only to a metal and it becomes -1
when is the oxidation number of oxygen not -2?
when it’s in a peroxide (-1) or with a fluorine (+2)
e.g in H2O2 hydrogen peroxide, oxygen is -1
what is the oxidation number of N in NaNO3?
Na = +1
O3 = -2 (-6)
so N = +5
what is the oxidation number of Mn in MnO4 -?
O4 = -2 (-8)
so Mn = +7
bc has a negative overall charge
does an increase in oxidation number mean oxidation or reduction?
oxidation (loosing an electron)
does a decrease in oxidation number mean oxidation or reduction?
reduction (gaining an electron)
when working out oxidation numbers, do balancing numbers have any impact??
(5HNO3)
no
what is the formula of aluminium?
Al 3+
what is a chemical symbol?
what is a formula?
14 N
7
H2O or NaCl
what is an ionic equation?
Na+ (aq) + Cl- (aq) —> NaCl (s)
split up the (aq) into their separate elements, then get rid of the spectator ions
they show chemical species as DISSOCIATED IONS with INDIVIDUAL CHARGES
what is an ionic compound?
they are made up of positive and negative ions, held together by electrostatic attraction
e.g NaCl or Al2O3
if nothing changes on either side of the equation when working out the oxidation number, what does it mean?
it’s not a redox reaction
what does OIL RIG stand for?
oxidation is loss
reduction is gain
what are the ions that don’t change when working out the oxidation numbers called?
spectator ions
what is the name of the type of redox reaction where a single substance is both oxidised and reduced?
disproportionation reaction
what does OIL A RIG stand for
OIL
A
RIG
oxidation agent = gain
reducing agent = loss??
what is the formula and charge of silver?
Ag +
what is the formula and charge of hydrogencarbonate?
HCO3 -
what is the formula and charge of phosphate?
PO4 3-
what does a disproportionation reaction mean?
the SAME ELEMENT has been reduced and oxidised
what is the oxidation number of NO3?
-1
what is an ionic equation?
they only show the reacting ions and can be written for any reaction involving ions in solution
what do they mean when they ask to calculate the molar mass?
the Mr
bromine
magnesium
oxygen
sodium
which two of these elements together produce the most ionic bond? why?
oxygen and sodium
- they have the largest electronegativity difference
2 C6H5CHO + H2O -> C6H5CH2OH + C6H5COOH
state why this reaction is classified as disproportionation [1]
either:
- the aldehyde is being oxidised to a carboxylic acid and reduced to an alcohol
- the aldehyde gains oxygen forming a carboxylic acid and gains hydrogen forming an alcohol