Covalent bonds, Miscible/immiscible, Metallic bonding

Question 1

What is a covalent bond?

Answer 1

A pair of electrons shared between two atoms.

Question 2

Simple molecular covalent substances have ________ bonds between the atoms and ______ bonds between the molecules.

Answer 2

Strong, weak.

Question 3

Name 4 properties of simple molecular covalent substances.

Answer 3

• They do not conduct electricity.
• Low boiling points.
• Low melting points.
• Usually liquids or gases at room temp.

Question 4

Name 2 giant molecular covalent substances.

Answer 4

Diamond and graphite.

Question 5

Why are melting points high in giant molecular covalent substances? (2)

Answer 5

• They have very strong bonds.

- It takes a lot of energy to break these bonds.

Question 6

Explain why graphite conduct electricity but diamond can’t. (3)

Answer 6

• Graphite has 3 carbon bonds and diamond has 4.
• This means in graphite there is one electron from each carbon atom that can move along the layers.
• This allows it to conduct electricity.
• There are no free electrons in diamond.

Question 7

True or false:

Simple molecular covalent substances have weak intermolecular forces.

Answer 7

True.

Question 8

How would you separate 2 immiscible substances? (3)

Answer 8

• Pour into separating funnel.
• Place beaker underneath and open tap until the lower liquid in the the beaker and there’s only the other left in the funnel.
• Close the tap, switch beakers and then open the tap.

Question 9

How can you obtain oxygen and nitrogen from liquid air?

Answer 9

Fractional distillation.

Question 10

Nitrogen (l/g/a) is collected from the ___ of the column and (l/g/a) oxygen is collected from the _____ of the column.

Answer 10

Nitrogen, gas, top

Oxygen, liquid, bottom

Question 11

How can you liquify air? (3)

Answer 11

• Cool the air so water freezes and is removed.
• The remaining air is cooled to -200 ℃.
• This makes it liquid.

Question 12

In the fractioning column liquid air is warmed to ____. This causes the nitrogen to ______ __ the column. Most of the oxygen stays as a _______ and is piped out of the ______.

Answer 12

• 185℃
  Rise up
  Liquid
  Bottom

Question 13

True or false:

-185℃ is above nitrogens boiling point but below oxygens boiling point.

Answer 13

True

Question 14

Why are metals malleable?

Answer 14

This is because the atoms roll over each other into new positions without breaking the metallic bond.

Question 15

What metal is not solid at room temperature?

Answer 15

Mercury.

Question 16

Transition metals form ________ compounds.

Answer 16

Coloured.