An unknown material has a mass of 6.25 g and a volume of 7.75 cm3. what is the density of the material? round to the nearest tenth.

density equals:  806451.61290323

The density is 0.8064516129.

Explanation:

To find the density of any object, you need to know the Mass (grams) of the object, and its Volume (measured in mL or cm³). Divide the mass by the volume in order to get an object's Density. And das what I did.

it is b that is the answer.

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.