Chemistry

Question 1

What is it called when a solid converts straight to a gas?

Answer 1

Sublimation

Question 2

What is it called when a gas transforms straight to a solid?

Answer 2

Deposition

Question 3

What does a sharp melting or boiling point suggest about a substance?

Answer 3

The substance is pure

Question 4

What is avogadro’s number?

Answer 4

6.022 x 10 to the power of 23

Question 5

Mass=

Answer 5

Moles x relative atomic mass (Mr)

Question 6

Moles=

Answer 6

Mass divided by relative atomic mass (Mr)

Question 7

Relative atomic mass (Mr)

Answer 7

Mass divided by moles

Question 8

One mole of Carbon atoms balls have a mass of 12.000 g. Calculate the mass of one Carbon atom (answer to 3 significant figures).

Answer 8

12 divided by 6.022 x 10 to the power of 23= 1.99 x 10 to the power of minus 23

Question 9

What mass of propane could burn in 48.0 g of oxygen? C(3)H(8)+ 5O(2)→ 3CO(2)+ 4H(2)O?

Answer 9

48 divided by 32=15
15 divided by 5= 0.3
0.3 x (36+8)= 13.2g

Question 10

What is the sequence of how many electrons are on each shell?

Answer 10

2, 8, 8, 2

Question 11

Explain melting

Answer 11

When an ice cube melts, the surroundings transfer energy to the ice meaning that the particles start to move faster and move away from regular patterns.

Question 12

Explain freezing

Answer 12

When a liquid freezes the liquid has lost energy so the particles start moving slower until they eventually stop moving and freeze.

Question 13

What is a melting point?

Answer 13

The point at which a substance melts is called it’s melting point

Question 14

What can we do with melting points?

Answer 14

We can check if a substance is pure or not, a pure substance has a sharp melting point because it has only one type of atom.