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Flashcards in My C1 Deck (43)
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1
Q

what is the overall charge on a atom?

A

neutral (zero)

2
Q

what is the charge of a proton?

A

1

3
Q

what is the charge of a neutron?

A

0

4
Q

what is the charge of an electron?

A

-1

5
Q

what is the central part of an atom called?

A

nucleus

6
Q

what particles do you find in the nucleus of an atom?

A

protons and neutrons

7
Q

what is the relative size of a proton?

A

1

8
Q

what is the relative size of a neutron?

A

1

9
Q

what is the relative size of an electron?

A

very small (negligable)

10
Q

what does the atomic number tell you in the periodic table?

A

how many protons it has (and also how many electrons)

11
Q

what does the mass number tell you in the periodic table?

A

how many protons + neutrons are in the nucleus

12
Q

how many electrons can the first three shells hold?

A

2, 8, 8

13
Q

if an atom gains one electron, what will it’s charge be now?

A

-1

14
Q

if an atom loses one electron, what will it’s charge be now?

A

. + 1

15
Q

what is the chemical formula for ‘calcium carbonate’?

A

CaCO3

16
Q

what is the main chemical found in limestone?

A

calcium carbonate

17
Q

what is made when calcium carbonate is heated?

A

calcium oxide and carbon dioxide

18
Q

what is thermal decomposition?

A

breaking down a chemical using heat

19
Q

what is the word equation for the thermal decomposition of calcium carbonate?

A

calcium carbonate –> calcium oxide + carbon dioxide

20
Q

what is the symbol equation for breaking down calcium carbonate using heat (thermal decomposition)?

A

CaCO3 –> CaO + CO2

21
Q

calcium oxide + water = ?

A

calcium hydroxide

22
Q

what is calcium hydroxide used for?

A

neutralisation. It is an alkali (farmers might use it on their fields to neutralise soil)

23
Q

calcium hydroxide + more water = ?

A

calcium hydroxide solution (LIMEWATER!)

24
Q

What happens to limewater when you add carbon dioxide?

A

goes cloudy

25
Q

how do we test for carbon dioxide?

A

add it to limewater and see if it turns cloudy

26
Q

What is cement made from?

A

Limestone and clay heated up

27
Q

what is concrete made from?

A

cement, sand and aggregate (rocks/stones)

28
Q

what is mortar made from?

A

cement and sand

29
Q

put these metals in order of reactivity (most reactive first) - copper, gold, potassium, aluminium.

A

potassium, aluminium, copper, gold

30
Q

why does gold stay shiny for a longer time than copper?

A

gold is less reactive

31
Q

what is phytomining?

A

phytomining uses plants to absorb metal compounds and that the plants are burned to produce ash that contains the metal compounds

32
Q

what is bioleaching?

A

bioleaching uses bacteria to produce leachate solutions that contain metal compounds.

33
Q

how are unreactive metals removed from the earth?

A

Unreactive metals such as gold are found in the Earth as the metal itself but most metals are found as compounds that require chemical reactions to extract the metal.

34
Q

how is carbon used to remove metals from their ores?

A

Metals that are less reactive than carbon can be extracted from their oxides by reduction with carbon, for example iron oxide is reduced in the blast furnace to make iron.

35
Q

how are metals more reactive than carbon mostly removed from their ores?

A

Metals that are more reactive than carbon, such as aluminium, are extracted by electrolysis of molten compounds. The use of large amounts of energy in the extraction of these metals makes them expensive.

36
Q

why is it expensive to remove aluminium and titanium from their ores?

A

there are many stages in the processes and large amounts of energy are needed.

37
Q

why is recycling metals a good idea?

A

We should recycle metals because extracting them uses limited resources and is expensive in terms of energy and effects on the environment.

38
Q

what is steel?

A

Steels are alloys since they are mixtures of iron with carbon. Some steels contain other metals.?

39
Q

what is an alloy?

A

a mixture of metals

40
Q

Describe some examples of different steels and their properties

A

?Low-carbon steels are easily shaped, high-carbon steels are hard, and stainless steels are resistant to corrosion.

41
Q

why are gold, copper and aluminium often made into alloys?

A

Pure copper, gold, iron and aluminium are too soft for many uses and so are mixed with small amounts of similar metals to make them harder for everyday use.

42
Q

what is copper useful for?

A

Copper has properties that make it useful for electrical wiring and plumbing. is a good conductor of electricity and heat
can be bent but is hard enough to be used to make pipes or tanks
does not react with water.

43
Q

why are aluminium and titanium very useful?

A

Low density and resistance to corrosion make aluminium and titanium useful metals.