Studied by 2 people
What is an atom
The smallest part of an element that can take place in chemical reactions
What is the relative charge of a proton
+1
What is the relative charge of a neutron
0
What is the relative charge of an electron
-1
What’s the relative mass of a proton and neutron
1
What’s the relative mass of an electron
1/1836
What does an atoms atomic number mean
The number of protons within the nucleus
What does an atoms mass number mean
The number of protons and neutrons within the nucleus
What is an ion
A charged atom
What is a cation
A positively charged ion
What’s an anion
A negatively charged ion
What are isotopes
Atoms of the same element that contain the same number of protons and electrons but a different number of neutrons
why do isotopes have the same chemical properties
because they have the same number of electrons in their outer shells which then take part in chemical reactions
Why do isotopes have different physical properties
They have a different number of neutrons which changes the atoms mass and density
What is relative mass
The mass of an atom relative to the mass of 1/12 of a Carbon-12 atom
What is relative isotopic mass
The mass of an isotope relative to 1/12 of a Carbon-12 atom
What’s relative atomic mass
The weighted mean mass of an atom relative to 1/12 the mass of a carbon-12 atom
What’s the equation for working out the relative atomic mass of an element
(Relative abundance of isotope 1 x mass isotope 1) + (relative abundance isotope 2 x mass isotope 2) / 100
How can the percentage abundance of the isotopes of an element be found
Using a mass spectrometer
What is the process of mass spectrometry
The sample is vaporised then ionised to form cations then the ions are accelerated and the ions are detected as a mass to charge ration (m/z) and produce a signal in accordance to their abundance
What’s relative molecular mass
The formula of a compound that has a fixed formula in terms of the number of atoms involved
What is relative formula mass
The formula of a compound that uses an empirical formula to represent them
What are ionic compounds composed of
A metal and non-metal bonded together
What are Roman numerals used for
To show the charge/oxidation state
What is formula and charge of a silver ion
Ag +
What’s the formula and charge of an ammonium ion
NH4 +
What’s the formula and charge of a Zinc(II) ion
Zn 2+
What’s the formula and charge of a hydroxide ion
OH -
What’s the formula and charge of a nitrate ion
NO3 -
What’s the formula and charge of a sulfate ion
SO4 2-
What’s the formula and charge of a carbonate ion
CO3 2-
What’s the formula and charge of a hydrogen carbonate ion
HCO3 -
What’s the formula and charge of a phosphate ion
PO4 3-
What’s happens to ionic compounds in aqueous solutions
They dissociate into their ions
What are ions that do not take part in a reaction called
Spectator ions
What do ionic equations show
The ions taking part in a reaction not spectator ions
What are the units for amount of substance
Moles
What is avogadros constant
The number of particles equivalent to the relative atomic molecular or formula mass of a substance
What is the value of avogadros constant
6.02 × 10(23) g mol -1
What is molar mass
The mass in grams of one mole of substance
What is the molar mass equation
Moles = mass/molar mass
What is the molar gas volume
The volume occupied by one mole of any gas at room temperature and pressure
What is the molar volume equal to
24 dm3
What is a molecular formula
A formula showing the number and type of each atom in a molecule
What is an empirical formula
The simplest whole number ratio of the elements present in one molecule of the compound
What is the molecular formula equation
Relative molecular mass of the molecular formula/ relative formula mass of the empirical formula
What is water of crystallisation
When compounds can form crystals which have water as part of their structure
What is a compound containing water of crystallisation called
A hydrated compound
What is a compound that doesn’t contain water of crystallisation called
An anhydrous compound
How do you calculate the degrees of hydration
Measure the mass of the hydrated salt, heat the salt until it reaches a constant temperature, use the two values to calculate the number of moles of water in the hydrated salt
What is the concentration of a solution
The amount of solute dissolved in a solvent to make 1dm3 of solution
What is a concentrated solution
A solution that has a high concentration of solute
What’s a dilute solution
A solution with a low concentration of solute
What is the equation connecting number of moles, concentration and volume
Moles = concentration x volume
What’s stoichiometry
Using balanced equations to find out what mass of chemicals react in a reaction
What does the kinetic theory of gases state
That molecules in gases are constantly moving
What assumptions does the kinetic theory of gases make
That gas molecules are moving very fast and randomly, that molecules have hardly any volume, that gas molecules do not attract or repel, that no kinetic energy is lost when gas molecules collide, that the temperature of the gas is related to the average kinetic energy of the molecules
What does the kinetic theory of gases describe
Ideal gasss
What factors affect the volume that an ideal gas occupies
It’s pressure and temperature
What is the relationship between volume and temperature of ideal gases at constant pressure
They’re directly proportional
What are limitations of the ideal gas law
At low temperature and high pressure real gases don’t obey the kinetic theory
What is the ideal gas equation and define each element
P (pressure) x V (volume ) = n (number of moles) x R (gas constant) T (temperature)
What’s the temperature conversion between kelvin and Celsius
0 degrees Celsius = 273 kelvin
What’s the ideal gas constant
8.314
What is room temperature and pressure
101 KPa and 298 K
What are reasons for low percentage yield
Side reactions, incomplete reaction, products lost
What is percentage yield
How much of a particular product you get from the reactants in comparison to the maximum theoretical amount you could get
What’s the percentage yield equation
Percentage yield = (actual yield/theoretical yield) x 100
What is atom economy
How many of the atoms used in the reaction become the desired product
What is the atom economy equation
Atom economy = (molecular mass of desired product/sum of molecular masses of all reactants) x 100
In which reactions will the atom economy always be 100%
Addition reactions
what are the key ideas behind green chemistry
finding reaction pathways with high percentage yield and high atom economy
What’s a strong acid
An acid that fully dissociates in solution
What’s a weak acid
An acid that only partially dissociates in solution
What’s a neutralisation reactio
A reaction where an acid and base react to form water and a salt
What’s formed in the reaction of a metal and acid
Salt and hydrogen
What are signs that a stronger acid if reacting with a metal
More effervescence, faster time to dissolve, more exothermic reaction
What’s formed in the reaction of metal oxides/hydroxides and acids
Salt and water
What’s formed in the reaction of acids and metal carbonates
Salt, water and carbon dioxide
What’s volumetric analysis
A process that uses the volume and concentration of a standard solution to determine the concentration of another unknown solution
What pieces of equipment can be used to measure volumes precisely
Volumetric/graduated pipette and a Burette
What are the steps to preparing a standard solution
Weigh out a precise amount of solid, add to a small volume of water and dissolve the solid, transfer to a volumetric flask, rinse out the beaker with distilled water and add to the flask, make up to the mark with water
What are the steps of performing a standard solution
Measuring a known volume of one solution with a volumetric pipette and adding to a conical flask, placing the other solution into the burette, add a few drops of indicator to the solution in the conical flask, open the tap of the Burette and add the solution drop by drop swirling between drops until the indicator changes colour, repeat until concordant results are obtained
What are concordant results
Results that are within 0.05 cm3 of each other
What’s the percentage uncertainty equation
Percentage uncertainty = ( uncertainty/measured value ) x 100
What’s oxidation state
The charge that would exist in an individual atom if the bonding was completely ionic
What’s the oxidation number of group 2 elements
+2
What’s the oxidation number of fluorine
-1
What’s the oxidation number of hydrogen and what’s the exception to this
+1 (expect in metal hydrides where it’s -1)
What’s the oxidation number of oxygen and what’s the exception
-2 (except in peroxides where it’s -1)
How do you determine which element in a compound has a positive oxidation state
The more electronegative one will have the negative value
What’s a redox reaction
A reaction where both oxidation and reduction occur
What’s oxidation
The loss of electrons or gain of oxygen
What’s reduction
The gain of electrons or loss of oxygen
What’s an oxidising agent
A compound that oxidises something else and is reduced
What’s a reducing agent
A compound that reduces something else and is oxidised
What’s an electron configuration
The arrangement of electrons in an atom
How are electrons arranged around the nucleus
In principal energy levels
What are principal energy levels split into
Subshells
Where is the 4s subshell found relative to the 3d subshell
Below it
