Answer:
True.
Explanation:
An exothermic reaction has a positive enthalpy (heat) of reaction. However, it can be negative in some circumstances.
Activation energy is a thermodynamic barrier that must be overcome before products are formed in a reaction. It is the minimum amount of energy needed for a reaction to occur. The energy can be in the form of kinetic or potential energy. This concept was introduced by Svante Arrhenius, which brought about the Arrhenius equation which is a formula used to determine rate of reactions.
Answer:Artificial light from cities has created a permanent "skyglow" at night, obscuring our view of the stars. Here's their map of artificial sky brightness in North America, represented as a ratio of "natural" nighttime sky brightness. In the black areas, the natural night sky is still (mostly) visible.
Explanation:
Answer:
M
Explanation:
Henry's law relational the partial pressure and the concentration of a gas, which is its solubility. So, at the sea level, the total pressure of the air is 1 atm, and the partial pressure of O2 is 0.21 atm. So 21% of the air is O2.
Partial pressure = Henry's constant x molar concentration
0.21 = Hx1.38x
H = 
H = 152.17 atm/M
For a pressure of 665 torr, knowing that 1 atm = 760 torr, so 665 tor = 0.875 atm, the ar concentration is the same, so 21% is O2, and the partial pressure of O2 must be:
P = 0.21*0.875 = 0.1837 atm
Then, the molar concentration [O2], will be:
P = Hx[O2]
0.1837 = 152.17x[O2]
[O2] = 0.1837/15.17
[O2] = M
Explanation:
The answer to questions are
A) 4
B) 3
C) 5
D) 3
E) 3
