Methane is the compound CH4, and burning it uses the reaction:
CH4 + O2 -> CO2 + H2O, which is rather exothermic. To find the heat released by burning a certain amount of the substance, you should look at the bond enthalpy of each compound, and then compare the values before and after the reaction. In methane, there are 4 C-H bonds, which have bond energy of 416 kj/mol, resulting in a total bond energy of 1664 kj/mol. O2 is 494 kj/mol. Therefore we have a total of 2080 kj/mol on the left side. On the right side we have CO2, which has 2 C=O bonds, each at 799 kj/mol each, resulting in 1598 kj/mol, and H2O has 2 O-H bonds, at 459kj/mol each, resulting in a total of 2516 kj/mol on the right hand side. Now, this may be confusing because the left hand side seems to have less heat than the right, but you just need to remember: making minus breaking, which results in a total change of 436kj/mol heat evolved.
Now it is a simple matter of find the mols of CH4 reacted, using n=m/mr.
n = 9.5/16.042 = 0.592195 mol
Therefore, if we reacted 0.592195 mol, and we produced 436 kj for one mol, the total amount of energy evolved was 436*<span>0.592195 kj, or 258.197 kj.</span>
However, as a result of the Sun's large angular size, solar<span> illumination is only partially blocked in the outer portion of the Earth's </span>shadow<span>, which is given the name penumbra. A penumbral </span>eclipse<span> occurs when the Moon passes through the Earth's penumbra. The penumbra causes a subtle darkening of the Moon's surface.</span>
Answer:
Oxygen is in excess.
Explanation:
The coefficients of the balanced equation create a mole ratio that shows the ratio of how many reactants are used up and products are created.
The mole ratio of Mg to O2 in this equation is 2:1, which means that for every two moles of Mg used, there will be 1 mole of O2 used.
If we have 3.00 moles of Mg, we will only need 1.5 moles of oxygen to completely burn the Mg. Therefore, when all 3.00 moles of Mg are used, there will still be some of the 2.20 moles of oxygen remaining.
