Chemistry Flashcards 3 -
What is the test for oxygen?
Test for hydrogen?
The test for CO2?
- It relights a glowing splint if oxygen is present
- a squeaky-pop is heard if hydrogen is present
- When bubbling through limewater it turns cloudy if CO2 is present
What is the formula for the mass of the element or compound?
- The number of moles in a sample x Mr
What group has the reactivity series?
Group 1
What is the collision theory? (Two)
- A reaction can only take place when particles (atoms, ions and molecules) of reactants come together
- The reacting particles must bump into each other with enough energy to cause a chemical reaction to take place.
When are reactions more likely to happen between reactant particles? (Two)
- Increase the frequency of collisions between reacting particles
- Increase the energy the reacting particles have when they collide
What 3 techniques are used to collect ‘rate of reaction’ data?
- Measuring the decreasing mass of a reaction mixture
- Measuring the increasing volume of a gas given off
- Measuring the decreasing light passing through a solution
How does surface area affect the rate of reaction? (Two)
- The larger the surface area of a solid reactant, the faster the rate of reaction
- Because more surface area of the solid reactant will be exposed to the other reactant (more collisions per second)
How does the concentration of a solution affect the rate of reaction? (Two)
- The higher the concentration of a liquid reactant, the faster rate of reaction
- Because there are more reactant particles in the given volume, resulting in a higher number of collisions
How does the pressure of a reactant affect the rate of reaction? (Two)
- If a reaction involves gases then the higher the pressure, the faster the rate of reaction
- Because there are more reactant particles, resulting in more collisions
How does the temperature of a reactant affect the rate of reaction? (Two)
- The higher the temperature, the faster the rate of reaction
- Because the reactant particles have more kinetic energy resulting in a higher number of collisions
How does the presence of a catalyst affect the rate of reaction? (Two)
- A catalyst is a substance that speeds up the reaction without being involved in the reaction itself
- They speed up the reaction because a catalyst lowers the activation energy, resulting in a higher number of collisions
concentration equation?
Concentration = mass/volume
Why is electrolysis used to extract some metals?
To separate metal ions from a solution or molten substance and deposit them as pure metal at the electrodes
What are the properties of crude oil? (Two)
- Black, sticky, smelly liquid
- A mixture of hydrocarbons
What is a hydrocarbon?
Hydrocarbons are compounds that contain hydrogen and carbon only!
How is crude oil formed? (Four stages)
- Plankton (tiny, marine creatures) died and sank to the bottom of the ocean. (takes millions of years)
- These formed a marine deposit
- The layer of plankton got covered by sand/mud removing oxygen
- Heat and pressure turned mud into sedimentary rock - thus plankton turns into crude oil.
Test for alkenes
Bromine water and goes clear
How and where can crude oil be separated? (Two)
- Crude oil can be separated into different hydrocarbons by fractional distillation
- This occurs in a fractioning column/fractionating tower
What are the alkane key points? (three)
- They are found naturally all mixed up in crude oil
- The alkanes are hydrocarbons - they contain carbon and hydrogen only
- All alkanes only contain single carbon-carbon bonds, so are described as saturated
What is the formula for alkanes?
CnH2n+2
The bigger the alkane… (Four)
- The higher the boiling point
- The more viscous it is (thick and sticky)
- The less flammable
- The less easily it evaporates into a gas
What is oxidation?
What is combustion? What does it require?
The gaining of oxygen by a substance
Special oxidation reaction, in which substances react with oxygen (burning - requires oxygen, fuel and heat).
What is the test for water?
White anhydrous copper sulfate turns blue when it comes into contact with water
What are the structures of ionic compounds?
Giant lattice structures
