Amole of the element u (uranium) and a mole of co2:

have the same molecular weight
have the same atomic mass
have an equal number of particles
have an equal number of atoms

The correct answer is they have same number of particles.

Explanation:

According to mole concept:

1 mole of an element or compound contains  number of particles.

The number is known as Avogadro's number.

We are given:

One mole of uranium element and 1 mole of carbon dioxide molecule.

These two substances have same number of particles equal to Avogadro's number.

Hence, the correct answer is they have same number of particles.

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b