GCSE Chemistry C3 - Energy, Acids, Reversible Reactions and Organic Chemistry Flashcards
propanol, methanol and ethanol are all alcohols. Which one is found in drinks?
Ethanol
2H2 + O2 < –> 2H2O. Assuming all theses are gases, does increasing the pressure increase or decrease the yield?
It increases it as increasing pressure favours decreasing number of molecules.
A reversible reaction that is exothermic in the forward direction is heated - what happens to the yield?
It decreases
A reversible reaction that is endothermic in the forward direction is heated - what happens to the yield?
It increases
What is ‘combustion’?
Burning in oxygen
What is the pH of a solution of methanol in water?
pH 7 - neutral
What does ‘ionise’ mean in relation to an acid?
the acid molecule splits up to form a positive H+ ion and a negative ion.
What is produced when sodium is added to ethanol?
Hydrogen gas and a salt (sodium ethanoate)
Give 2 uses of any alcohol
solvent, fuel
What is activation energy?
The amount of energy required to make a reaction happen
What is the unit used to measure energy?
Joules
What is made when ethanol is oxidised?
ethanoic acid
What is meant by a reaction that has reached equilibrium?
When a reversible reaction is happening in both directions at the same rate
What is calorimetry measuring?
The amount of energy released when a substance burns.
What temperature change is associated with an exothermic reaction?
An increase - heat given out
Ethanoic acid is the main ingredient in which condiment?
vinegar
Ethanoic acid has the functional group COOH. To which family of compounds, all with this group, does it belong?
carboxylic acids
How can ethanol be oxidised?
chemical oxising agents or microbes+ oxygen in air.
What are esters used for?
flavourings and perfumes
What temperature change is associated with an endothermic reaction?
Temperature decrease - heat energy is taken in.
carboxylic acid + alcohol =?
ester
Carboxylic acids are weak acids. What does this mean?
They do not ionise completely when dissolved in water.
