Topic 7 Flashcards
rate of reaction
speed at which reactions turn to products
measure the rate of reaction by
- how quickly the reactants are used up
- how quickly the products are made
how to increase the rate of reaction
- add a catalyst
- heat
- increase concentration
- increase surface area
why is it better to record at several points during the reaction
- increases reliability
- calculate the mean
two units for the rate of reaction
g/s cm3/s
enzymes
biological catalysts
speed up reactions inside living cells
glucose
yeast ( ——>) ethanol + co2
yeast
yeast needs sugar to grow
the enzymes in the yeast cells catalyse the reaction that converts sugar into glucose and alcohol co2
this is called a fermentation reaction
in beer the yeast is needed to produce the alcohol ethanol (anaerobic respiration)
In the bread industry both alchahol and co2 are formed
the alchahol evaportates during backing and co2 makes the bread rise ( arebobic repiration)
examples of exothermic reactions
respiration
examples of endothermic reactions
photosynthesis
why has the solution tured cloudy?
- look for soilid
- precipitate formed (solid)
why are catalysts used
- less energy needed
- reduced cost
incomplete reaction
Carbon, carbon monoxide, water
bonds made
energy released
bonds broken
energy made
Explain how Figure 17 shows that dissolving ammonium chloride in water is an
endothermic process.
A has more energy than B
heat has increased
so energy has been taken in
Explain, using these results, the type of heat energy change that occurs when calcium
chloride dissolves in water.
temepratre has incraesed
exothetmic
Explain, in terms of bond breaking and bond making, why some reactions are exothermic.
ENDO- BONDS MAKING
EXO - BONDS BREKING
MORE ENERGY IS BROKEN THAN MADE
Give the name of the apparatus that could be used to measure 1.00 g of calcium chloride.
weighing scale
Explain why the pack goes cold.
solid reacts with water
endothemic, heat taken in
enthylpy chnage
energy change in a chemical reaction
triangl H
KJ/mol
activation energy
minimum amount of energy required fot two particles to successfully collide and react
can be lowered by use of a catalyst
