Answer: NO.
Explanation: Oxygen is not a compound. It has only one element in it.
At stp (standard temperature and pressure), the temperature is T=0 C=273 K and the pressure is p=1.00 atm. So we can use the ideal gas law to find the number of moles of helium:

where p is the pressure (1.00 atm), V the volume (20.0 L), n the number of moles, T the temperature (273 K) and

the gas constant. Using the numbers and re-arranging the formula, we can calculate n:
Answer: D. Hydroelectric power
Explanation: Hydroelectric means water power (not exactly but "hydro" is water and electric is well self explanatory)
<u>Answer:</u> runoff water is water from rain, snow, or other sources, that flows through the land, and is a major component of the water cycle.
Answer:
The electron's speed is 34007.35 m/s
Explanation:
It is given that,
Magnetic field, B = 0.34 T
Magnetic force on the electron, 
The electron follows a helical path. We have to find the speed of an electron. The formula for magnetic force is given by :

q = charge on an electron, 
v = velocity of an electron


v = 34007.35 m/s
Hence, this is the required solution.