chemistry Flashcards

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1
Q

what factors will you investigate if you were investigating fuels

A
  • how much energy they produce
  • what pollutants they produce
  • how a fuel is chosen for specific purposes, heating rooms and cooking
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2
Q

what type of reaction is the combustion of fuels

A

exothermic, energy is released

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3
Q

what is the equation for combustion is fuels

A

fuel + oxygen = (arrow) carbon dioxide + water (+ heat energy)

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4
Q

what is the rule when balancing combustion equations

A
1C = 1CO2
2H = 1H2O
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5
Q

what does it mean in combustion when there is a longer carbon chain

A

the more energy is released during combustion

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6
Q

what are factors to consider when choosing a fuel

A
  • how easy it is to ignite
  • how easy it is to store
  • how easy it is to transport
  • how much/type of pollution it produces
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7
Q

what is flammability

A
  • fuels are flammable, this means that they easily catch fire
  • it is a hazard as there is a risk of fire and burns when working with fuels
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8
Q

what is toxicity

A

many fuels contain impurities that are toxic, fossil fuels normally contain benzene which is toxic
they produce combustion of impurities such as sulfur impurities being released as sulfur dioxide

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9
Q

what is sulfur dioxide

A

reacts with moisture in the air to produce acid rain

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10
Q

what is wrong with acid rain

A
  • erodes limestone buildings and statues
  • acidifies lakes and rivers
  • kills acidifies lakes and rivers
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11
Q

why does combustion happen

A

because there is plenty oxygen present

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12
Q

what is the type of combustion that happens when there is limited oxygen

A

incomplete combustion

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13
Q

what does incomplete combustion produce

A

carbon monoxide and soot

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14
Q

what is the formula for incomplete combustion

A

fuel + oxygen (arrow) carbon monoxide + water ( + heat energy)

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15
Q

what is bad about carbon monoxide

A

a poisonous gas and can cause headaches, dizziness, nausea and death

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16
Q

what is wrong with soot

A

causes respiratory problems

17
Q

what is energy measured in

A

Joules

18
Q

what is specific heat capacity

A

4.2 joules of energy to raise the temperature of 1 g of water by 1 degree

19
Q

how many kelvins equal 1 degree

A

274k = 1 degree

20
Q

what is the formula for specific heat capacity

A

heat energy (j) = mass of water (g) X specific heat capacity of water (4.2 j) X temperature rise of water

21
Q

how do you calculate the energy released of a fuel (heat of combustion)

A

heat of combustion (kJ mol) = heat energy supplied to water (kJ) x relative molecular mass of fuel/ mass of fuel burnt (g)

22
Q

how do you convert kilojoule to joules

A

1 kJ = 1000 J

23
Q

how do you convert kilometre to meter

A

1 km= 1000 m

24
Q

how do you convert kilogram to gram

A

1 kg = 1000g