A student adds iron filings to a copper(II) chloride solution at room temperature. A balanced equation
for the reaction that occurs is shown below.
Fe(s) + CuCl2(aq) - FeCl2(aq) + Cu(s)
Which of the following changes would most likely
increase the reaction rate?
A. using larger pieces of iron
B. performing the reaction in an ice bath
C. decreasing the volume of the CuCl2 solution
D. increasing the concentration of the CuCl2
solution

what is the question here. i think you messed up.

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.