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=
=
= 
<span>chemical properties is the changes in chemical manner of a
substances. Antacid tablets neutralize stomach acid is a chemical properties (it is an acid) which produce new products... salt and water
The others are physical properties</span>
Researchers have shown that when really small particles are close to each other like in a nebula, they are attracted to each other due to electromagnetism (from static electricity) since the masses are too small for gravity to really matter. However, the answer is probably gravity, electromagnetism only played a small role in the very beginning when nothing had enough mass. After that, gravity caused everything to condense and gravity did a better job once everything had enough mass for gravity to matter.
I hope this helps, let me know if anything is unclear in the comments.
Color change. Smell change. Or temperature change. All are signs of chemical reaction