Arun and Marcus are asked to compare the solubility of two salts in water at room temperature. The two salts are labelled X and Y 1) name the independent variable in the investigation
2) name the dependent variable in the investigation
3) list the control variables in the investigation

1) Salts X and Y

2) The solubility of the salts

3) a) The solvent

b) The solvent temperature

Explanation:

1) The independent variable is the variable that is suspected to be the cause of the subject of the investigation

The given investigation is meant to investigate the solubility of different salts

Therefore, the solubility is expected to be dependent on the type of salt, and the independent variable is the type of salt, X or Y

2) The dependent variable is the effect meant to be observed in the investigation, which is the solubility of the salt in water at room temperature

3) The control variables are the variables which are held constant during the investigation, including;

a) The solvent used if the investigation; water

b) The temperature of the solvent; Room temperature

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.