Answer:
The correct answer would be C) Support
Your answer is B and the element is Carbon
So what your looking for is matching isotopes. Isotopes are elements that are the same in amount of protons but different in mass meaning different number in neutrons. Because when you add the total protons and neutrons together you get your atomic mass. So this can be written as X=said element, top number above=different atomic mass, bottom number below=atomic number. Hope this help!!
Be careful because answer A has same masses but different atomic numbers so different atoms(elements)!!!
Answer:
69.8 kilo Pasacl is the pressure of the hydrogen gas.
Explanation:

Pressure at which hydrogen gas collected = p = 101.2 kilo Pascals
Vapor pressure water =
= 31.4 kilo Pascals
The pressure of hydrogen gas = P
The pressure at which gas was collected was sum of vapor pressure of water and hydrogen gas.


69.8 kilo Pasacl is the pressure of the hydrogen gas.
<span>As mentioned, the isomerization of cyclopropane to propylene is a first-order process with a half-life of 19 min at 500°c. A first-order reaction kinetic rates means that the rate is constant throughout the reaction.
Thus, the time it takes for the partial pressure of cyclopropane to decrease from 1 atm to 0.125 atm at 500°c is </span><span>57 minutes.</span>