3.1 Metals and electrochemical cells Flashcards

1
Q

What is metallic bonding?

( LO 1)

A

The attraction between positive ions and delocalised electrons

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2
Q

Why do metals conduct electricity?

( LO 2)

A

The (outer) electrons are delocalised and free to flow between outer shells

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3
Q

What are the 3 reactions of metals?

( LO 3)

A

With oxygen

With water

With acid

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4
Q

What is the product of reacting metals with oxygen?

A

A metal oxide

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5
Q

What are the products of reacting metals with water?

( LO 3b )

A

A metal hydroxide plus hydrogen

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6
Q

What are the products of reacting metals with acids?

( LO 3c )

A

A salt plus hydrogen

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7
Q

How many electrons do metal lose?

A

The number of outer electrons they have

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8
Q

What charge is on metal ions?

A

The positive charge equivalent to the number of electrons they have lost.

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9
Q

How does the reactivity of metals affect their reactions with water, acids, and oxygen?

( LO 4 )

A
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10
Q

How are soluble salts made using metals?

( LO 5 )

A
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11
Q

What is meant by oxidation?

( LO 6b )

A

The loss of electrons

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12
Q

Why do metals lose electrons when they react?

A

To obtain a full valence shell

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13
Q

What do we call naturally occurring metal compounds?

A

Ores

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14
Q

What are the 3 ways of extracting metals from ores?

A

Electrolysis ( Al and above)

Heating with carbon ( Cu to Mg)

Heating ( Below Cu)

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15
Q

What type of bonding is found in almost all metallic compounds?

A

Ionic bonding

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16
Q

What do we call the process of making metal ions into metal atoms during extraction?

( LO 10 )

A

Reduction (gain of electrons)

17
Q

What are the 3 methods of extracting metals and which metals can be extracted by each method?

( LO 11 )

A
18
Q

What is electrolysis?

( LO 13 )

A

The breaking apart of an ionic substance using electricity

19
Q

What type of current is used in electrolysis and why?

( LO 14 )

A

DC current

To ensure separate products form at each electrode

20
Q

What reaction happens at the negative electrode during electrolysis?

( LO 15 )

A

Reduction of metal ions into metal atoms.

21
Q

What reaction happens at the positive electrode during electrolysis?

( LO 15 )

A

Oxidation

Negative ions lose electrons to form atoms (usually as molecules)

22
Q

What is an electrochemical cell?

A

An arrangement that produces electricity through a chemical reaction (redox)

23
Q

What is the set up for a simple electrochemical cell?

A
24
Q

What is an electrolyte?

A
25
Q

What is the purpose of the electrolyte?

A

To complete the circuit

26
Q

Where does the reaction(s) take place in an electrochemical cell?

A

On the surfaces of the electrodes (metal strips)

27
Q

In which direction do the electrons flow in an electrochemical cell?

A

From the metal higher in the electrochemcial series to the metal lower

28
Q

Why is the flow of electrons through the wire lower than it should be in a simple cell?

A

The metal electrode that is losing electrons is in direct contact with the aqueous ions accepting them allowing direct displacement

29
Q

How do we eliminate the possibility of direct displacement in an electrochemical cell?

A

We use a “half cell” arrangement.

30
Q

What is the basic half cell arrangement using 2 metals?

A

2 metals sit in solutions containing their own ions. Both these solutions are joined by a salt (or ion) bridge

31
Q

What are the 2 purposes of the salt (ion) bridge in a half cell arrangement

A
  1. To complete the circuit
  2. To maintain the charge balance in the cell
32
Q

Why do cells “run out” and stop working?

A

The redox reaction stops due to chemicals running out.

33
Q

What are advantages of using an electrochemical cells rather than mains electricity?

A
  • safety
  • portability
34
Q

What are disadvantages of using an electrochemical cells rather than mains electricity?

A
  • voltage limitations
  • cost
  • need replaced or recharged