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Z AS Chemistry: Unit 1 > Energy from Fuels > Flashcards

Flashcards in Energy from Fuels Deck (22)
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1
Q

Heat

A

The thermal energy of an object

2
Q

Temperature

A

A measure of hotness

3
Q

Specific heat capacity

A

The energy required to raise the temperature of 1g of a substance by 1˚C

4
Q

∆H = …

A

∆H = total energy needed to break bonds - total energy released when bonds form

5
Q

Bond energy

A

The amount of energy required to break one mole of a type of chemical bond. Breaking bonds requires energy; making bonds releases energy

6
Q

Exothermic

A

Energy is given out to the surroundings in the reaction; ∆H is negative

7
Q

Endothermic

A

Energy is taken in from the surroundings in the reaction; ∆H is positive

8
Q

∆Hcᶿ

A

Standard molar enthalpy change of combustion: the enthalpy change when one mole of a substance in its standard state at a specified temperature and pressure (298K, 25˚C; 1 atmosphere) is completely combusted in air

9
Q

∆Hfᶿ

A

Standard molar enthalpy change of formation: the enthalpy change when one mole of a substance is formed from its elements in their standard states at a specified temperature and pressure (298K or 25˚C; 1 atmosphere)

10
Q

Hess’s Law

A

The enthalpy change for a reaction is independent of the route taken. Routes begin when arrows diverge and end when they converge again

11
Q

Homologous series

A

A group of molecules with similar chemical or physical properties

12
Q

Carbon

A

The first group 4 element of the periodic table, Carbon forms strong covalent bonds with itself to form rings and chains (catenation).

13
Q

Isomers

A

Elements with the same molecular formula but different arrangements of atoms

14
Q

Allotropes

A

Different forms of the same elements

15
Q

Alkanes

A

Saturated, non polar hydrocarbons with general formula CnH2n+2. Physical properties, such as melting point and density, change as the number of carbon atoms increases

16
Q

Alkenes

A

Unsaturated, non polar hydrocarbons with general formula CnH2n

17
Q

Cycloalkanes

A

Ring-shaped hydrocarbons with general formula CnH2n

18
Q

Arenes

A

Ring compounds with general formula CnHn, e.g. benzene

19
Q

Full structural formula

A

All the atoms and their bonds written out in full

20
Q

Shortened structural formula

A

Bonds are shown only between sub-molecules (e.g. CH3, CH2)

21
Q

Skeletal formula

A

Links between carbon atoms are shown as lines; hydrogen is not shown

22
Q

Molecular formula

A

Written shorthand for molecules: CxHy