Calculate the mass of 10cm3 of a 0.4g/dm3 solution of sodium carbonate

0.004g

Explanation:

Given parameters:

Volume of sodium carbonate  = 10cm³;  this is also 0.01dm³

Density of solution = 0.4g/dm³

Unknown:

Mass of the solution   = ?

Solution:

To solve this problem, we must understand that ;

 Mass  = density x volume

 So;

        Mass = 0.4 x 0.01  = 0.004g

they are made of gases.

they have a spherical shape.

they make energy through fusion.

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.