4.2 non exam qs Flashcards
Whats sulfuric acids formula
H2SO4
whats hydrochloric acids formula
HCl
Whats nitric acids formula
HNO3
Whats phosphoric acids formula
H3PO4
Whats carbonic acids formula
H2CO3
how is something an acid
acids release h+ ions in aqueous solutions
Metals below hydrogen wont do what?
react with dilute acid but can react with concentrated acid
metal + acid —>
salt + hydrogen
which is in excess and which is limiting reactant in the salt + acid equation?
metal is in excess,, acid is the limiting reactant
metal oxide + acid —>
metal salt + hydrogen
metal carbonate + acid –>
metal salt + water + CO2
whats the method to making salt?
using a measuring cylinder, measure 25cm of acid/a into a beaker of cone
warm the acid
add excess metal/ metal oxide/ metal carbonate until more dissolves and some solid is left at the bottom
filtration - using filter paper and funnel and conical flask to filter out excess solid
pour into evaporating basin, evaporate until crystals form on rim, sols now saturated, leave basin on window sill 4 water to evporate and crystals to appear, pat dry w/ filter paper
how can soluble salts be made?
from reacting insoluble bases w/ acids
what is a base
a substance that neutralises acid ( metal oxide, metal carbonate etc)
base + acid —>
salt + water
what is a strong acid
a strong acid will completely ionise to produce H+ ions
whats THE neutralisation reaction equation?
H+ + OH- –> H2O
what does a weak acid do
partially ionises releasing few H+ ions in aqueous solution
whats a dilute acid
whats a concentrated acid
a small amount of acid (H+ IONS) per unit volume of solution
bigger amount of acid per unit volume of solution
how does the strength of an acid relate to rate of reaction
a strong acid is more reactive than a weak acid of the same concentration
how can an acid be both strong and dilute
acids dilute when theres a small amount of acid per unit volume but strong because it completely ionises to form H+ ions in water
what is pH
a measure of H+ ion concentration
what happens to H+ ion concentration as pH increases
H+ ion concentration decreases (inverse scale)
whats a pure substance
a single element or compound not mixed with any other substance
pure elements and compounds do what
melt and boil at specific temperatures
what do impurities do in regards to state change
lower melting points , increase melting ranges and they increase boiling points and cause a range of boiling temperatures
whats a formulation
a mixture that has been designed as a useful product
whats a complex mixture
each chemical has a specifc purpose
how are formulations made
by mixing the components in carefully measured quantities to ensure that the product has the required properties
what are examples of formulations
fuels, cleaning agents, paint, medicine , alloys , fertilisers , some food
how to know if the mixtures a formulation
materials a mixture, material serves a purpose, components in mixture are measured in specific amounts
whats the stationary phase
a solid or liquid, eg the chromatography paper
whats the mobile phase
a liquid or gas, (eg a solvent)
what does separation of components in a mixture depend on?
the distribution of substances between the two phases
substances w/ a greater attraction to the paper do what?
move less distance
substances with less solubility in the solvent do what
move less distance
what are the two ways of testing for the positive ion
flame test, sodium hydroxide test
what are the 3 ways of testing for the negative ion
carbonate test
sulfate test, halide test
what are the results of the sodium hydroxide test for magnesium, calcium and aluminium, copper, iron (III) AND Iron (ii)
mag- white ppt
cal - white ppt
aluminium- white ppt, redissolves in excess NaOH so forms colourless solution
copper- blue ppt
iron (ii) - green ppt
iron (iii) -brown ppt
what is the carbonate test
add acid (whichever) to the solution, observe effervescence and collect gas with a pipette and place into limewater to test if it goes cloudy
what colour does chloride, bromide and iodide turn in the halide test?
cl -white
br- cream
i- yellow
what are the advantages of instrumental analysis
theyre accurate, sensitive and rapid
and
are particularly useful when the amount of a sample is very small making them more useful compared to chemical analysis
how does flame emission spectroscopy work
the sample is put into a flame and the light given out is passed through the spectroscope, the output is a line spectrum that can be analysed to identify he metal ions in the sol and measure their concentration
specific emission line spectra are produced by specific metal ions
whys the flame emission spectroscopy better than flame testing?
it can identify the metal ions present in a mixture and determine their concentrations ( more conc = more intense line spectre)
