Answer:
0.00559 mol
Explanation:
The following data were obtained from the question:
V = 140mL = 0.14L
T = 296K
P = 98.2kPa = 98200Pa
Recall: 101325Pa = 1atm
98200Pa = 98200/101325 = 0.97atm
R = 0.082atm.L/Kmol
n =?
The number of mole (n) can be obtained as follows:
PV = nRT
n = PV /RT
n = (0.97x0.14)/(0.082x296)
n = 0.00559 mol
Therefore, the number of mole of the gas present is 0.00559 mol
A beaker of black powder can be a mixture with different substances (i.e gunpowder: a mixture of sulfur, charcoal, etc.), an element which can probably be carbon (known as black), and a compound as well which can be potassium nitrate. Hence, the answer is D.
There is a very simple relationship between the three. First off, power is the amount of energy used over a certain amount of time. Energy is the capacity of carrying out that power. Lastly, time depends on how much energy you have to exert the work.
Hope this helps :)