Chemistry

Question 1

What is the equation for gas volumes?

Answer 1

Moles = Volume / 24

Question 2

Conversion: 1cm^3 to 1dm^3

Answer 2

/1000

Question 3

Which direction do the electrons flow in a fuel cell?

Answer 3

Anode to cathode

Question 4

Concentration, mass and volume?

Answer 4

Concentration = Mass / Volume

Question 5

Explain, in terms of particles and forces, how a solid turns into a liquid. (6)

Answer 5

• In solids, strong attractive forces hold particles in place
• So they can only vibrate in fixed positions
• When heated, particles gain kinetic energy
• Which causes the particles to vibrate faster and faster
• Eventually, particles overcome forces and melts

Question 6

Why do alkali metals become more reactive going down the group?

Answer 6

• Going down the group, atomic radius increases
• This means there is more shielding, and therefore weaker electrostatic attraction between the nucleus and outer electron.
• This means less energy is required to lose the outer electron, and for a reaction to occur.

Question 7

What’s the most accurate way to measure rate of reaction?

Answer 7

Change in mass, because scales are the most accurate measure.

Question 8

How can you calculate rate of reaction?

Answer 8

• Use a balance to monitor how the mass changes over time
• Take measurements at regular intervals
• Plot results on a graph w/ tangent and find the gradient

Question 9

What happens if you increase the concentration of the reactants? (Le Chatelier’s principle)

Answer 9

The equilibrium will shift to the right, reducing the reactants concentrations and restore equilibrium.

Question 10

What are four properties of graphene?

Answer 10

Strong, conducts electricity, light, and high boiling point

Question 11

Are noble gases diatomic?

Answer 11

No, they’re monoatomic. Idiot…

Question 12

What indicator is used in titrations?

Answer 12

Methyl orange

Question 13

Describe the structure and bonding of graphite. (or draw it)

Answer 13

• Giant covalent lattice
• Each carbon atom is bonded to 3 others
• Between atoms are covalent bonds
• Separate sheets held together by intermolecular forces
• Delocalised electrons

Question 14

Describe the structure and bonding of metals.

Answer 14

• Giant structure
• Delocalised electrons
• Metal ions are arranged in a regular lattice structure
• Strong metallic bonds between positive metal ions and negative del. electrons

Question 15

(What’s the equation) for atom economy?

Answer 15

Mr of desired products / Mr of reactants

Question 16

How do you test for hydrogen?

Answer 16

It burns rapidly with a ‘pop’ when you apply a lighted splint

Question 17

How do you test for oxygen?

Answer 17

It relights a glowing splint

Question 18

How do you test for carbon dioxide?

Answer 18

When bubbled through limewater, it turns the solution cloudy

Question 19

How do you test for chlorine?

Answer 19

It bleaches damp blue litmus paper white

Question 20

How do you calculate retention factor?

Answer 20

Distance moved by substance / Distance moved by solvent