Question 1

1. exothermic
2. C3H8 + 5O2 → 3CO2 + 4H2O
3. alcohol, carboxylic acid
4. powdered coal has more surface area so rate of reaction increases as there are more frequent successful collisions and energy is released more quickly.

Question 2

1. 4, 5
2. solar power uses renewable energy source which is the sun which means that is infinite and will not run out but fossil fuels are finite. this is better than the environment because it does not release any emissions compared to fossil fuels.
3. A
4. C and Si are in group 4 which means that they need to form 4 covalent bonds to have a complete outer shell and be stable. they have 4H to complete the outer shell.

Question 3

1. different reactivity based on the reactivity series and the elements electronegativity. more reactive materials means that more hydrogen gas will be produced.

2. catalyst increases rate of reaction by providing the reaction and alternate pathway and reduces activation energy increasing speed of reaction without being used up itself.

3. Mr CH4 = 12+4 = 16

   n = m/Mr

   n = 8000/16

   n = 500 mol

   1:3 ratio

   500 x 3 = 1500 mol

4. Ammonia is more stable and less flammable than hydrogen

5. less co2 in the atmosphere so lower contribution to the environment. co2 is not released

Question 4

1. before freezing → liquid no arrangement but particles are touching

   after freezing → solid square

2. measure

3. x axis: temperature (degrees celcius)

   y axis: percentage of ice cream frozen (%)