DF 1 and general knowledge

Question 1

what is crude oil and where is it from

Answer 1

• crude oil is a fossil fuel
• formed from the remains of dead organisms from millions of years ago trapped underground

Question 2

what is crude oil made of

Answer 2

• a mixture of hydrocarbons

Question 3

what are alkanes and their general formula

Answer 3

-saturated hydro carbons, so there are only single bonds between atoms and they are unreactive
-Cn H2n+2

Question 4

name the hydrocarbon prefixes from 1-10 carbons

Answer 4

Meth..
Eth..
Prop..
But..
Pent..
Hex..
Hept..
Oct..
Non..
Dec..

Question 5

What is the difference between the structural formula and the molecular formula

Answer 5

the molecular formula is is the condensed version of the structural formula

Question 6

What is the difference between the structural formula and the molecular formula

Answer 6

the molecular formula is is the condensed version of the structural formula

Question 7

explain the trend that comes with the increasing amount of carbons in a hydrocarbon

Answer 7

as the amount of carbons increase, the molecule gets bigger and the larger the amount of intermolecular forces, the state also changes from gas to liquid to solid

Question 8

draw the skeletal structure of heptane

Answer 8

/\/\/\

Question 9

how would you test for an alkene

Answer 9

alkenes would decolourise bromine water when reacting with it

Question 10

what happens to molecules with longer chains

Answer 10

Longer chain mol. not very reactive or flammable. due to strong intermol. forces
cracked to produce a mixture of alkanes and alkenes

Question 11

what is the general formula for alkenes

Answer 11

Cn H2n

Question 12

what are the molecular shapes and bond angles of alkanes and alkenes

Answer 12

alkanes- tetrahedral 109.5
alkenes- trigonal planar 120

Question 13

what is the general formula of an alkyl

Answer 13

Cn H2n+1

Question 14

what is the letter formula that is present in every:
-carboxyl
-ester
-amide

Answer 14

-COOH
-COO
-CO

Question 15

how to find ^H

Answer 15

H products - H reactants

Question 16

difference between endothermic and exothermic reactions

Answer 16

bonds are being broken during endothermic reactions, so the system takes in energy from surroundings
bonds are being formed in exothermic reactions, the system releases energy into the surroundings

Question 17

what are the standard conditions when comparing reactions

Answer 17

Temperature - 298K
Pressure - 100 kPa
Concentration - 1 mol/dm -3

Question 18

define absolute 0

Answer 18

temperature of 0K or -273’C

Question 19

define the standard enthalpy change of combustion

Answer 19

enthalpy change when one mole of substance is burnt completely with oxygen under standard conditions

Question 20

define the standard enthalpy change of formation

Answer 20

enthalpy change when one mole of substance is made from its elements with both the elements and the substance in standard states

Question 21

define the standard enthalpy change of neutralisation

Answer 21

enthalpy change when one mole of hydrogen ions react with one mole of hydroxide ions to form one mole of water under standard conditions

Question 22

how to calculate energy changes

Answer 22

mass of water x specific heat capacity x temperature change