545924
Descrição
Mapa Mental por Francesca Floris, atualizado more than 1 year ago
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Criado por Francesca Floris
mais de 10 anos atrás
|
|
C3 Chemical
economics-
Rate Of Reaction
(1)
- Fast and slow
reactions
- Measuring
Rates
- The rate of reaction measures how much product is formed in a certain time.
- The mass of a solid product is often measured in grams while the volume
of a gaseous product is often measured in cm3.
- The time period chosen may depend upon the rate of the reaction. For example, it
may be a few seconds for a fast reaction or a few minutes for a slow reaction.
- The units for rate of reaction are commonly written as:
- g/s or g/min
- cm3/s or cm3/min
- g/s or g/min
- The rate of reaction measures how much product is formed in a certain time.
- Measuring the rate where a
gas is produced
- The apparatus needed depends on the nature of the
product being measured:
- The volume of a
gas is usually
measured with a
gas syringe, or
sometimes an
upside-down
measuring cylinder
or burette
- The mass of a
substance - solid,
liquid or gas - is
measured with a
balance
- The volume of a
gas is usually
measured with a
gas syringe, or
sometimes an
upside-down
measuring cylinder
or burette
- The apparatus needed depends on the nature of the
product being measured:
- Measuring
Rates
- Calculating the Rate Of Reaction
- Gradient = y/x
- Rate of reaction can be worked out from the
gradient of a graph
- Gradient = y/x
- Limiting Reactants
- A reaction stops when all the particles of
one of the reactants are used up.
- For example, magnesium reacts with hydrochloric
acid. When the reaction is over: Magnesium is the
limiting reactant if it is all gone at the end Hydrochloric
acid is the limiting reactant if some magnesium is left at
the end
- For example, magnesium reacts with hydrochloric
acid. When the reaction is over: Magnesium is the
limiting reactant if it is all gone at the end Hydrochloric
acid is the limiting reactant if some magnesium is left at
the end
- In a reaction involving
two reactants:
- The reactant in excess is still there at the end of the
reaction (although in a smaller amount than at the start)
- The limiting reactant is the one that is all
used up at the end of the reaction
- The reactant in excess is still there at the end of the
reaction (although in a smaller amount than at the start)
- Directly proportional
- The amount of product formed in a reaction is directly
proportional to the amount of limiting reactant used.
- This means that a graph showing
amount of product formed against
amount of limiting reactant will give a
line that:
- Is straight
- Has a
positive
gradient
- Passes through
the origin (0,0)
- Is straight
- The amount of product formed in a reaction is directly
proportional to the amount of limiting reactant used.
- Reactions happen when particles collide with enough energy. The more
reactant particles there are to begin with, the more product can be formed.
This is why the amount of product formed is directly proportional to the amount
of limiting reactant used.
- A reaction stops when all the particles of
one of the reactants are used up.
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