7. Chemical Reaction Flashcards
(19 cards)
Describe the effect of particle size on rate of reaction
Lower particle size, higher rate because small particle have more surface area in which particle can collide
Describe the effect of concentration on rate of reaction
Higher concentration, higher rate because particles have more chance of colliding
Describe the effect of catalyst on rate of reaction
Speed up reaction and remaining chemically unchanged
It lowers the activation energy so reaction can take place with less energy
Describe the effect of temperature on rate of reaction
Higher temperature higher rate
Describe light sensitive reaction
Light provides energy for the reaction
Higher light intensity, higher rate of reaction
Describe the reaction of silver salt
Surface of b&w photo film contains tiny crystals of silver bromide
When light shine on, silver bromide breaks down by silver ions accept electrons from the bromide ions and become silver atom. It is reduced
2ag+ + 2e- -> 2ag
Describe photosynthesis
The reaction between carbon dioxide and water in the presence of chlorophyll and sunlight (energy) to produce glucose and oxygen
Define reversible reaction
Reactions which can go both ways depending on the condition
Product can react to form the original reactant again
Define equilibrium reaction
Both forward and reverse reactions are going on at the same time
Features of equilibrium reaction
Reactants or products must not escape from the reaction mixture - closed system
Can be approached from either direction
Can start with only the reactant/product. Whichever we start with. We end up with fixed concentration of reactant and product in the mixture
Rate of forward reaction = reverse
Dynamic equilibrium
Concentration of the reactant and product does not change
What is dynamic equilibrium
The reactant are continually being changed to products and products are being changed back to reactants
Describe the effect of pressure on the position of equilibrium
Only affect the reactant where there is a gas in the equation
Higher pressure moves the equilibrium to side with smaller number of moles so that the overall number of molecules is reduced.
Lower pressure moves the equilibrium to side with larger number of moles
Equal volume -> no effect
Describe the effect of temperature on the position of equilibrium
Higher temperature, it moves in the endothermic direction
Lower temperature, it moves in the exothermic direction
Describe the effect of concentration on the position of equilibrium
Decrease reactant/ increase product
-> move it to the reactant side
Increase reactant/ decrease product
Move it to the product side
What is oxidation
Gain of oxygen
Loss of electron
What is reduction
Loss of oxygen
Gain of electron
Removal of hydrogen from a compound
What is redox reaction
Involve both oxidation and reduction at the same time
Describe the color changes of potassium manganate (VII) in redox reaction
In acidic solution it is a good oxidant
When it oxidize a substance, it color changes from purple to colorless
It can be use as a test for reductant
Describe the color changes of potassium iodine in redox reaction
In acidic solution it is a good reductant
When it reduces a substance, it’s color changes from colorless to brown
It can be use as a test for oxidant
