Rates of reactions
State two ways to increase the rate of a chemical reaction
This type of bonding involves the sharing of electrons between non-metal atoms.
covalent bonding
What is the independent variable in an experiment?
The independent variable is the factor that is deliberately changed.
What is meant by one mole of a substance?
One mole is the amount of substance containing 6.02×1023 particles
This piece of equipment is used to accurately measure a fixed volume of liquid during a titration. Normally holds the ACID
Burette
Explain why increasing temperature increases the rate of reaction using collision theory.
When temperature increases:
These particles move freely in metallic bonding and allow metals to conduct electricity
Delocalised electrons
What is meant by a fair test
A fair test is an experiment where only one variable is changed and all other conditions are kept the same.
Calculate the number of moles in 24 g of carbon.
(Atomic mass of C = 12)
2 moles
This gas turns limewater milky.
Carbon Dioxide
A student reacts:
The powdered calcium carbonate reacts faster.
Explain why.
Powdered calcium carbonate has a larger surface area than marble chips.
This means:
Therefore, the reaction is faster.
This type of bond forms when electrons are transferred from a metal to a non-metal.
Ionic
What is the dependent variable?
The dependent variable is the factor that is measured or observed.
How many moles are present in 88 g of carbon dioxide, CO₂?
(Mr of CO₂ = 44)
2
Why did Mendeleev leave gaps?
he believed some elements had not yet been discovered.
Explain how a catalyst increases the rate of a reaction.
A catalyst lowers the activation energy of a reaction.
This means more particles have enough energy for successful collisions, so the reaction happens faster.
Which group from the periodic table is the least likely to react? AND WHY?
What is the difference between accurate and precise?
Accurate - correct
Precise - wrong, but results close
Calculate the number of molecules in 2 moles of water.
1.204×1024 molecules
What does Amphoteric mean?
An amphoteric substance is one that can act as both an acid and a base.
Explain why increasing temperature increases the rate of reaction using the Maxwell–Boltzmann distribution.
When temperature increases:
Therefore, there are more successful collisions and the reaction rate increases.
Sodium chloride has a high melting point because of these strong forces between oppositely charged ions.
Electrostatic force of attraction
In an experiment investigating how temperature affects reaction rate, name:
1 mole of gas occupies how many Dm3
24
What is the test for hydrogen?
POP test