If the penny color is changed, will the mass change? and why?

answer:

explanation:

in 1943, the content of the coin was changed to zinc coated steel because of the copper shortage during world war ii. then after 1982, the compostion was 97.6% zinc, and 2.4% copper. so this means that the pennies made before 1982 will have a different mass from those made after 1982.

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.