Scientific laws and theories have different jobs to do. A scientific law predicts the results of certain initial conditions. ... In contrast, a theory tries to provide the most logical explanation about why things happen as they do.
Answer: 4.15234 m
512 g H2O *
= 0.512 kg H2O
Nitric Acid: HNO3 = 1.008 + 14.007 + 3(15.999) = 63.012 g/mol
H = 1.008 g/mol
N = 14.007 g/mol
O3 = 3*15.999
134 g HNO₃ *
= 2.126 mol
m =
= 4.15234 m
The most viscous among the choices is D. Honey at room temperature.
Viscosities of liquids typically vary with temperature. The higher the temperature, the lower the viscosity. Among the choices, only motor oil and honey appear to be the most viscous. The clue that helps determined the answer are the words "hot" and "room temperature". Hot motor oil is less viscous, while honey at room temperature is more viscous. Even comparing their viscosities at room temperature, honey already has a higher viscosity than motor oil.
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>