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GCSE Chemistry > Corrections > Flashcards

Corrections Flashcards

1
Q

Name 2 industries that use enzymes in its production process

A

brewing
baking

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2
Q

What is a catalyst (3)

A
  • increases rate of reaction
  • not used up during the reaction
  • lowers activation energy
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3
Q

formula for rate of reaction using formation of a product

A

= amount of product formed (or lost) / time

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4
Q

Why does a cross disappear in a reaction (2)

A

Because solid — is precipitated. The solid blocks view of the cross.

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5
Q

name an advantage of a inverted measuring cylinder over a gas syringe

A

none of the gas escapes before the syringe is connected

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6
Q

What is activation energy

A

Minimum amount of energy required for a reaction to take place

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7
Q

How does a larger surface area increase rate of reaction

A

more particles are able to be involved in collisions

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8
Q

How do you find rate of reaction at a specific point in a rate of reaction graph

A

draw a tangent and find the gradient

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9
Q

what happens to rate of reaction over time (2)

A

the rate decreases over time due to reactant particles being used up so there are fewer reactant particles

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10
Q

What is sulfur scrubbing (3)

A
  • exhaust gases containing sulfur dioxide are sprayed with ‘limestone slurry’.
  • The sulfur dioxide reacts with the slurry to form calcium sulfate
  • which is removed as solid waste
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11
Q

benefits of sulfur scrubbing (2)

A
  • reduces sulfur dioxide emissions reducing acid rain
  • solid calcium sulfate can be made into plaster boards
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12
Q

composition of modern atmosphere (4)

A
  • 78% nitrogen
  • 21% oxygen
  • 0.9% argon
  • 0.04% CO2
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13
Q

Where did ammonia from our previous atmosphere go

A

reacted with oxygen to form nitrogen gas and water.

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14
Q

use of nitrogen

A

unreactive atmospheres for food packaging

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15
Q

describe a test for the gas produced when carbonates decompose (2)

A
  • heat in a boiling tube with delivery tube
  • bubble gas through limewater and limewater turns milky
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16
Q

how are gases separated using fractional distillation (2)

A
  • they have different boiling points
  • gases collected at different places on the column in order of boiling points
17
Q

why didn’t scientists believe Alfred Wegener

A

he was unable to explain how continents moved

18
Q

2 pieces of evidence Alfred Wegener had of continental drift

A
  • similar fossil patterns on different continents
  • coastlines of continents fit together like a jigsaw
19
Q

What do all metal oxides look like

A

white solids

20
Q

ionic formulae for displacement reaction between sodium bromide + chlorine

A

2Br + Cl2 —- 2Cl + Br2

21
Q

why does mass decrease in a reaction

A

gas is released

22
Q

why are catalysts important in industrial processes

A

Reactions can take place at lower temperatures so less energy is needed therefore its cheaper to make the products

23
Q

common name for sodium carbonate

A

washing soda

24
Q

what does washing soda do

A

reacts with calcium and magnesium ions to produce insoluble salts

25
Q

What does boiling do

A

decoposes hydrogencarbonate ions

26
Q

how are oxygen and carbon dioxide levels in the atmosphere maintained

A
  • photosynthesis uses CO2 and releases O2
  • respiration uses O2 and releases CO2
  • balance is maintained when both oxygen and carbon dioxide are used up at the same rate they are produced
27
Q

safety measure in reaction of potassium with water

A

Use a small piece of potassium

28
Q

what is a practical problem when trying to get crystals to form at 4 degrees celsius and solution to this

A
  • it is lower than room temperature
  • difficult to get crystals to form
  • place the boiling tube in ice
29
Q

formula for decomposition of calcium hydrogen carbonate

A

calcium hydrogencarbonate + water + carbon dioxide

30
Q

what does adding washing soda to hard water form visibly

A

a white precipitate

31
Q

metal properties given in table with melting point, boiling point, density and conductivity (4)

A
  • high boiling point
  • high melting point
  • high density
  • being a conductor
32
Q

Describe the theory of plate tectonics

A
  • The Earth’s crust is divided into tectonic plates
  • these move very slowly
  • due to convection currents in the mantle
33
Q

what ions do group 1 elements form when they react

A

+1

34
Q

what ions do group 7 elements form when they react

A

-1

35
Q

describe a method of testing for water hardness (4)

A
  • add soap solution to each sample and shake
  • the one that produces a lather is soft water
  • boil the remaining samples
  • the one that lathers after boiling is temporary hard water and the one that does not is permanent hard water
36
Q

empirical formula =

A

mass\Ar. NOT Mr

GCSE Chemistry (6 decks)

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