Answer:
B. 
Explanation:
The unit for rate is M/s while the unit for each molecule should be M. You can find the unit for k by putting the units for rate and the molecules into the equation
rate= k{X][Y]
M/s= k *
* 
k= (M/s) / (
)
k= 
You can also use this predetermined formula to solve this problem faster: k= 
Where n is the number of molecule. There are 3 molecule(2X and 1Y) so n=3, so
k= 
k=
=
= 
Answer:
The process of elemental stratification relies on the diffusion velocity, which causes the migration of the different chemical elements within stars.
Explanation:
Answer:
The atomic mass on the periodic table is a decimal number because it is an average of the different isotopes of an element.
P.S.
An isotope is each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
Lead fluoride hope this helps