<u>Answer:</u> The amount of heat released is 56 MJ.
<u>Explanation:</u>
To calculate the number of moles, we use the equation:
Given mass of 
= 12 kg = 12000 g (Conversion factor: 1 kg = 1000 g)
Molar mass of = 30 g/mol
Putting values in above equation, we get:
The chemical reaction for hydrogenation of ethene follows the equation:
By Stoichiometry of the reaction:
When 1 mole of ethane releases 140 kJ of heat.
So, 400 moles of ethane will release = 
of heat.
Converting this into Mega joules, using the conversion factor:
1 MJ = 1000 kJ
So, 
Hence, the amount of heat released is 56 MJ.
Answer:
13. Index Fossils
14. Index Fossils
15. C
16. Geologists use index fossils to define geological periods.
17. C
18. A
Explanation:
bottom right = physical change
top left = chemical change
top right = physical change
bottom left = chemical change
<h3>A physical change is a change that goes from one form to another and physical changes can be reversed</h3><h3>example: water to ice or air to water</h3><h3 /><h3>A chemical change is when a substance combines with another substance and when it is combined it cannot be reversed</h3><h3>example: burning and or rusting</h3>
Answer:
C2H4O2 + 2O2 ==> 2CO2 + 2H2O
Explanation:
Start with the carbons
C2H4O2 + O2 ==> 2CO2 + H2O There are 2 on the left, so you need 2 on the right.
Next deal with the hydrogens. You have 4 on the left so you have to make 4 on the right
C2H4O2 + O2 ==> 2CO2 + 2H2O
The oxygens are the real devil in this question. Be careful how you handle them. There are 2 * 2 = 4 from the CO2 and 2*1 = 2 from the water. The total is 6
Now you can't just put a 3 in front of the O2. There are 2 in the given chemical. So you don't need 6. You need 6 -2 = 4. But the oxygen is O2. You have to divide the 4 by 2 to get 2
C2H4O2 + 2O2 ==> 2CO2 + 2H2O
And that's your answer.
