Reaction Rate + Organic

Question 1

What is a hydrocarbon

Answer 1

A molecule that contains carbon and hydrogen atoms only

Question 2

Define a saturated hydrocarbon

Answer 2

Hydrocarbon with only single covalent bonds between carbon atoms

Question 3

Why does one isomer have a higher melting point/boiling point

Answer 3

That isomer has a greater surface contact area. As a result, it will have stronger intermolecular dispersion forces, which means more energy is required to overcome them, and as a result a higher MP/BP

Question 4

What are the requirements for geometric isomerisms

Answer 4

1. Double bond between two carbons atoms (it is rigid so there is no free rotation about the carbon)
2. Different groups on the carbon

Question 5

Define homologous series

Answer 5

Groups of molecules that have the same functional groups, and as a result similar chemical properties. They also have the same general formula.

Question 6

Define a fuctional group

Answer 6

The reacting part of a molecule responsible for the molecules chemical properties

Question 7

What is meant by the term structural isomers

Answer 7

Same molecular formula, different structural formula as atoms are bonded in different order

Question 8

Describe an addition reaction with bromine

Answer 8

It is a test for a double bond. Clear colourless gas bubbled through orange. solution. The solution turns colourless.

Question 9

Requirements for addition reaction with hydrogen gas

Answer 9

Nickel catalyst, high temperature and high pressure

Question 10

Property of reaction with hydrogen halides

Answer 10

Can produce isomeric produces. However, both the alkene and the reactant must both be non symmetrical, as if they can be placed in position x and y, or y or x, producing different products.

Question 11

What are Arenes

Answer 11

Molecules that contain one ore more benzene rings, and only react in substitution reactions.

Question 12

Requirement of substitution reaction of benzene

Answer 12

only takes place with a catalyst

Question 13

Requirements for a reaction

Answer 13

1. Particles must have sufficient energy (overcome activation energy)
2. Collisions must occur
3. Collisions must have the correct orientation

Question 14

Difference between concentration and pressure

Answer 14

Concentration is used for solutions while solution is used for gas

Question 15

Describe the effect of a catalyst in a reaction

Answer 15

A catalyst provides an alternative reaction pathway with lower activation energy. This increases the proportion of reactant particles particles with kinetic energy which matches or exceeds the activation energy, increasing the proportion of collisions that are successful, increasing the frequency of successful collisions. This increases the rate of reaction.

Question 16

Describe the effect of increasing surface area.

Answer 16

Increasing the surface area provides an increased area for reactant particles to collide with, increasing the frequency of collisions, and as a result increases the frequency of successful collisions, increasing the rate of reaction.

Question 17

Describe the effect of increase temperature

Answer 17

Increases the average kinetic energy of particles. This results in an increased velocity of particles, resulting in an increase in the frequency of collisions between reactant particles. Additionally, there is an increased proportion of collisions with sufficient kinetic energy to overcome activation energy leading to an increased proportion of collisions that are successful. These two factor leads to an increased frequency of successful collisions. As a result, there is an increased rate of reaction.

Question 18

Describe the effect of increasing concentration.

Answer 18

Increases the number of reacting particles per volume, which increases the frequency of collisions. As a result, there is an increase in the frequency of successful collisions, increasing the rate of reaction.

Question 19

Accuracy

Answer 19

How well measure/calculated value matches accepted value, increased with sound experiment process and increasing precision.

Question 20

Validity

Answer 20

How well relevant controlled variables are maintained to ensure independent variable links directly to dependent variable without external factor influence. Increase validity by maintaining relevant controlled varables

Question 21

Reliability

Answer 21

How close results are to each other
Increased by increasing the number of trails and reducing human error

Question 22

Precisions

Answer 22

Precision is how close measured/calculated values are to one another. Increased using finely calibrated instruments and digital instruments.

Question 23

Conclusion

Answer 23

Did results support hypothesis?
Refer to research and explain the trend

Question 24

Evaluation

Answer 24

Talk about errors in measurement to do with procedure and equipment
Accuracy affected by systematic
Precision affected by random
if there is systematic error with equipment recalibrate

Question 25

systematic

Answer 25

error of measurement that skews results

Question 26

Describe the nature of bonding in alkanes, alkenes and benzene, using ideas of single and multiple bonds (π bonds), and delocalisation.
Sources

Answer 26

Alkanes contain only single bonds between carbon atoms. The carbons are sp3 hybridized and there is free rotation around the single bonds

Alkenes contain at least one carbon-carbon double bond. The atoms in the bond are sp2 hybridized and the double bond consists of one sigma and one pi bond.
The pi bond is formed by head on overlap of sp2 hybrid orbitals and the electrons are delocalized.

Benzene is a planar ring of six sp2 hybridized carbon atoms.
Each carbon forms three sigma bonds. The remaining p orbital on each carbon overlaps with neighboring p orbitals creating and delocalized pi bond system above and below the ring, where delocalized electrons are spread evenly around the ring.

Question 27

Explain why trans-2,3-dichloro-2-ene(A) is a liquid when butane(B) is a gas

Answer 27

Boiling point of A is greater than the boiling point of B. This is because A has both dispersion and dipole-dipole forces whilst B has only dispersion. As a result, the cumulative strength of IMF of A is greater than B. Hence a greater amount of energy is required to overcome the IMF in A compared to B, hence a higher BP.