Unit 2 - Nature's Chemistry Flashcards
1 mol
Formula mass in grams
Molar volume
The volume occupied by 1mol of gas at a given temperature and pressure.
Excess reactions
Moles, ratio, conclusion
Equilibrium
Equal rates of forward and backwards reactions. Constant concentrations.
% yield
Measures efficiency.
Atom economy
GFM x moles = mass
Plug in mass
Bond enthalpy
The energy required to break 1 mol of bonds between two atoms.
Bond enthalpy formula
ΔH = ΔEHbonds broken + ΔEH bonds made
Enthalpy definition
The measure of energy stored in a chemical.
Catalysed PE diagrams
Lower activation energy
Molar volume is _____ for all gasses at the same pressure and temperature.
The same
Le Chateliers Principle
An equilibrium will move to undo any change imposed upon it by temporarily favouring either the forward or backward reaction until a new equilibrium position is reached.
Steps to balancing ion-electron redox equations
- Balance main element
- Add water
- Add hydrogens
- Add electrons
An oxidising agent is..
a substance that accepts electrons
A reducing agent is…
a substance that donates electrons
Reducing agents have ___ electronegativity values.
low
Oxidising agents have ___ electronegativity values
high
Carboxylic acids are polar molecules and can therefore…
Hydrogen bond
Hydrogen peroxide is effective as..
Bleach
Unsaturated compounds ____ bromine water
rapidly decolourise
Saturated compounds ____ bromine water
Do nothing in
Factors on solubility, BP and MP
- hydrogen bonding
- PDs
- molecular size for LDFs
- polarities of solute and solvent
Smaller non-polar hydrocarbons like ethane are ______ volatile and have ______ BPs
More, lower
Smaller non-polar hydrocarbons like ethane are more volatile and have lower BPs because…
They have more electrons for LDFs
non-polar hydrocarbons ____ dissolve in water
Do not
Alcohol general formula
Cn H2n+1 OH
Primary alcohols
OH is joined to the end of the carbon chain
Secondary alcohols
Joined to a carbon in the middle of a carbon chain
Tertiary alcohols
Joins to a carbon which is attached to three other carbons
Alcohols conform hydrogen bonds because..
The -OH group makes them polar
More hydrogen bonds make a liquid more viscous because..
PD-PD interactions mean stronger intermolecular forces
Carboxylic acids react with
Bases
Metal oxide + carboxylic acid
salt + water
metal hydroxide + carboxylic acid
salt + water
metal carbonate + carboxylic acid
Salt + water + CO2
Acids contain
More H+ ions
Bases contain
More OH¯ ions
Carboxylic acids are acidic because they can break up…
to leave hydrogen ions in an aqueous solution
COOH becomes COO and H+
When salts are formed the H+ part of the acid
Is replaced by an alkali metal
lithium oxide + ethanoic acid
Lithium ethanoate + water
Potassium hydroxide + methanoic acid
Potassium methanoate + water
Calcium carbonate + propanoic acid
Calcium propanoate + water + CO2
In a condensation reaction
two molecules are joined together with the elimination of a smaller molecule
An ester link is formed by
A hydroxyl group and a carboxyl group
Esters are formed by
A condensation reaction between an alcohol and a carboxylic acid
Hydrolysis
A molecule is broken down into smaller molecules by reacting with water
Edible fats and oils are Esters formed by
The condensation of glycerol + three carboxylic acid molecules
Glycerol’s molecular formula
Propane-1,2,3-triol
The greater the degree of saturation in a fat, the ____ the MP, because..
Higher, double bonds prevent molecules packing closely together and weaken the van der waals forces
Biological uses of fats
- a concentrated source of energy
- transporting fat soluble vitamins in the body
Ethanol + ethanoic acid
ethyl ethanoate (ester) + water
Methanol + ethanoic acid
Methyl ethanoate (ester) + water
Ethanol (alcohol) + butanoic acid (carboxylic acid)
Ethyl butanoate (ester) + water
Ester uses
- Flavours
- solvents for np compounds
Ester BP
Low