Topic 2: Foundations in chemistry

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