How many atoms are in 2.54 mole O?

 1.505 * 10^24 atoms

Work Shown:

1 mole = 6.02 * 10^23 atoms

2.5*(1 mole) = 2.5*(6.02 * 10^23 atoms)

2.5 moles = (2.5*6.02) * 10^23 atoms

2.5 moles = (15.05) * 10^23 atoms

2.5 moles = (1.505 * 10^1) * 10^23 atoms

2.5 moles = 1.505 * (10^1*10^23) atoms

2.5 moles = 1.505 * 10^(1+23) atoms

2.5 moles = 1.505 * 10^24 atoms

This is true for any element. This value is an approximation since there are roughly 6.02 * 10^23 atoms in 1 mole of any element.

the answer

explanation:

the capillary tube was too close to the bottom of the beaker.

the ruler may have moved.

water got into the capillary tube.

the temperature was not allowed to equilibrate in the 2-4 minutes.

"the periodic table is arranged in order of atomic number."