Chem reactions extra notes Flashcards
Exothermic vs endo differences?
Exothermic-Heat energy is released into the surroundings.
Endothermic-Heat is absorbed by the surroundings
Endothermic-Temperature of the surroundings is decreased
Exothermic-temperature of the surrounding is increased
Endothermic-Enthalpy is positive
Exothermic-Enthalpy is negative
Endothermic-More energy in products than reactants
Exothermic-Less energy in the products compared to the energy in the reactants
2 examples of a exothermic reaction?
combustion. respiration, neutralization
2 examples of endothermic
Photosynthesis as sunlight is absorbed.
Cooking an egg in a frying pan-Energy being absorbed from the frypan to cook the egg.
2 examples of endothermic
photosynthesis, sodium hyrodgen
How is energy transferred in chemical reactions?
Through the breaking of chemical bonds in the reactants and creating new bonds in the products.
How do you know that a exothermic reaction has taken place
Through an increase in temperature from the reactants to the products.
what is meant by the term “thermal decomposition”?
To break down with heat.
three strong acids
sulphuric acid. nitric acid, hydrochloric acid.
weak acid
carbonic acid
strong base
sodium hydroxide
potassium hydroxide
sodium carbonate
weak base
ammonia
• Concentrated solution:
A concentrated solution is one that has lots of molecules in a volume of water.
• Dilute solution:
A dilute solution has very few molecules in a solution of water.
whats a weak acid
A weak acid is one that only partially ionises in water.
what’s a strong acid
A strong acid is one that almost fully ionises in water.
What polyatomic ion is this KNO3 ?
potassium nitrate
what polyatomic ion is this CaCO3
Calcium carbonate
What polyatomic ion is this Mg(OH)2
Magnesium hyrdroxide
what polyatomic ion is this Li3PO4
lithium phospate
what polyatomic ion is this NH4Br
Ammonium bromide
F. Na2SO4
Sodium sulfate
How is respiration similar to combustion -
Glucose combines with oxygen but doesn’t include burning a flame
C6H1206 + O2 -> CO2 + H20
Glucose + Oxygen -> Carbon dioxide + Water
Strong base
A molecule that almost fully protonates (accepts all hydrogen ions). Example - Ammonia (NH3)
Weak base
A molecule that does not protonate completely (doesn’t accept all hydrogen ions) Example - Sodium Hydroxide (NaOH)
What are antacids -
(Milk of Magnesium(Base)) used to relieve pain of too much acid from digestion of food. This is neutralisation.
Effects of combustion reactions -
Carbon dioxide produced during combustion reactions can react with water to produce acid rain or acidify oceans.
