Chemistry Flashcards

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1
Q

What is a life cycle assessment?

A

An analysis of the overall environmental impact that a product may have throughout its lifetime

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2
Q

What is distillation?

A

Purifying a liquid by heating and cooling

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3
Q

What are the two processes for obtaining copper from low-grade copper ores?

A
  • Using bacteria in a process called bioleaching
  • Using plants in a process called phytomining
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4
Q

What are the drawbacks of mining (Four)

A
  • Visual pollution
  • Sound pollution
  • Increased traffic in the area
  • Air pollution
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5
Q

What are the TWO methods of obtaining copper from the ore

A
  • Using sulfuric acid to produce copper sulfate solution, before extracting copper metal via displacement
  • Heating the copper ore to a high temperature in a furnace with air to produce impure copper
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6
Q

What are some of the general uses/needs for copper? (Three)

A
  • Electrical wiring
  • Construction
  • Home appliances
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7
Q

What happens during final treatment of sewage (Two stages)

A
  • In the last tank, the useful bacteria are allowed to settle out to the bottom of the tank as sediment.
  • Sometimes the water is filtered through a bed of sand, and then sterilised using UV
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8
Q

What happens during primary treatment (sedimentation)?

A

The waste water is allowed to stand still in the tank. heavier solids sink to the bottom creating sewage sludge. The sludge is then removed

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9
Q

What happens during screening? (Sewage)

A

Removes large objects using a large metal grid

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10
Q

What is an ion?

A

A charged particle (can be negative or positively charged.

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11
Q

What are the FOUR stages of sewage treatment

A
  • Screening
  • Primary treatment - sedimentation
  • Secondary treatment - aerobic digestion
  • Final treatment
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12
Q

Process of salt water -> potable water (via Distillation)

A

Heated until it boils. The salt is still in the liquid but when the steam cools and condenses it is pure potable water (An expensive water)

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13
Q

Process of salt water -> Potable water (Via osmosis).
And why is this more efficient in terms of energy?

A

Uses membranes to separate the water and salts dissolved in it. The membrane can catch 98% of dissolved salts.
- No heating required so uses less energy.

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14
Q

What is desalination

A

converting salty water to potable water

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15
Q

What are the physical properties of Group 7 elements (Three)

A
  • At room temperature the physical state changes as you go down the group.
  • The colours change as you go down the group.
  • The melting points and boiling points change as you go down the group.
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16
Q

What happens at the positive anode?

A

Negative anions lose electrons - they are oxidised

17
Q

What do these do in water?
1). Iron
2). Magnesium
3). Lithium
4). Sodium
5). Potassium

A

1). Iron - very slow reaction - some bubbles
2). Magnesium - Slow reaction - bubbles
3). Lithium - Fast reaction - floats, fizzes
4). Very fast reaction - floats, fizzes and forms a ball
5). Instant reaction - burns with a lilac flame, moves around

18
Q

What is an isotope?

A

Atoms of the same element with the same number of protons but DIFFERENT number of neutrons

19
Q

What do the symbols at the top and the bottom of an element mean

A

TOP: Relative atomic mass - protons + neutrons
BOTTOM: Atomic number: no. of protons

20
Q

What is chromatography?

A

This technique is used to separate substances that have a different solubilities

21
Q

What is the method of chromatography

A
  • Pencil line is drawn on chromatography paper and spots of different ink are put on it.
  • The paper is put into a beaker of water (the pencil line sits above the level of the solvent)
  • The ink will spread across the paper showing the pigments
22
Q

What is an element?

A

A substance that is 100% pure - each element is made up of just one type of atom

23
Q

What are the properties of metals and non-metals FOUR

A

METALS
- Higher melting & boiling points - tend to be solids at room temperature
- Silver-coloured
- Good conductors
- Malleable (can be shaped)

NON-METALS
- Lower melting and boiling points
- More likely to be colourful
- Poor conductors of heat and electricity
- Brittle (They snap/smash easily)

24
Q

How is an ion made?

A

An ion is made when an atom loses or gains electrons to have a full outer shell of electrons

25
Q

What are the properties of the alkali metals? (Three)

A
  • Silvery-coloured metals
  • They are soft and could be easily cut with a knife
  • They are highly reactive
26
Q

What was Ernest Rutherford’s theory?

A

By firing positively, charged alpha-particles at a gold sheet, he found that some passed through, while others deflected back. Rutherford had discovered the nucleus + disproved JJ Thomson.

27
Q

What model did these guys discover?
1). Ernest Rutherford
2). Niels Bohr
3). John Dalton
4). JJ Thompson

A

1). Nuclear model
2). Nuclear model 2.0
3). Solid sphere model
4). Plum pudding model

28
Q
A