Answer:
Nuclear fusion
Explanation:
Nuclear fusion is the source of Sun's energy.. At the core where temperature and pressure are very high hydrogen atoms fuse into helium atom and release energy in the form of Gama rays.
Answer:
A mixture has more than one things that are not fused chemically
Explanation:
Mixture comprises two or three compounds that aren't fused chemically. They have no physical interactions. A solution contains two substances that are chemically mixed to form a new compound. The chemical properties of each substances are retained without change.
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>
C) volume
.........
The volume of gas depends on e.g. temperature and pressure.
Answer:
Molar mass X = 18.2 g/mol
Explanation:
Step 1: Data given
Mass of compound X = 231 mg = 0.231 grams
Mass of benzene = 65.0 grams
The freezing point of the solution is measured to be 4.5 °C.
Freezing point of pure benzene = 5.5 °C
The freezing point constant for benzene is 5.12 °C/m
Step 2: Calculate molality
ΔT = i*Kf*m
⇒ΔT = the freezing point depression = 5.5 °C - 4.5 °C = 1.0 °C
⇒i = the Van't hoff factor = 1
⇒Kf = the freezing point depression constant for benzene = 5.12 °C/m
⇒m = the molality = moles X / mass benzene
m = 1.0 / 5.12 °C/m
m = 0.1953 molal
Step 3: Calculate moles X
Moles X = molality * mass benzene
Moles X = 0.1953 molal * 0.065 kg
Moles X = 0.0127 moles
Step 4: Calculate molar mass X
Molar mass X = mass / moles
Molar mass X = 0.231 grams / 0.0127 moles
Molar mass X = 18.2 g/mol
