Respuesta :

Answer:

B. [tex]\frac{1}{M^{2} s }[/tex]

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 * [tex]M^{2}[/tex] * [tex]M^{1}[/tex]

k= (M/s) / ([tex]M^{3}[/tex])

k= [tex]\frac{1}{M^{2} s }[/tex]

You can also use this predetermined formula to solve this problem faster: k= [tex]\frac{M^{1-n} }{s }[/tex]

Where n is the number of molecule. There are 3 molecule(2X and 1Y) so n=3, so

k= [tex]\frac{M^{1-n} }{s }[/tex]

k= [tex]\frac{M^{1-3} }{s }[/tex]= [tex]\frac{m^{-2}}{s}[/tex]= [tex]\frac{1}{M^{2} s }[/tex]