Which of the following has the most atoms per mole?

a. BaSO4
b. NaNO2
c. KMnO4
d. KCl
e. Na3PO4

e) Na₃PO₄

Explanation:

a) BaSO₄

1 mole of BaSO ₄ = 6.022×10²³ molecules

1 mole of BaSO ₄ contain 1 atom of Ba one atom of S and four atoms of O.

Total number of atoms = 6 atoms

6.022×10²³ × 6 atoms = 36.132 ×10²³ atoms

b) NaNO₂

1 mole of NaNO₂= 6.022×10²³ molecules

1 mole of NaNO₂ contain 1 atom of Na one atom of N and two atoms of O.

Total number of atoms = 4 atoms

6.022×10²³ × 4 atoms = 24.088 ×10²³ atoms

c)KMnO₄

1 mole of KMnO₄ = 6.022×10²³ molecules

1 mole of KMnO₄ contain 1 atom of K one atom of Mn and four atoms of O.

Total number of atoms = 6 atoms

6.022×10²³ × 6 atoms = 36.132 ×10²³ atoms

d) KCl

1 mole of KCl = 6.022×10²³ molecules

1 mole of KCl contain 1 atom of K one atom of Cl.

Total number of atoms = 2 atoms

6.022×10²³ × 2 atoms = 12.044 ×10²³ atoms

e) Na₃PO₄

1 mole of Na₃PO₄ = 6.022×10²³ molecules

1 mole of Na₃PO₄ contain 3 atom of Na one atom of P and four atoms of O.

Total number of atoms = 8 atoms

6.022×10²³ × 8 atoms = 48.176×10²³ atoms

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.