In which of the following does matter change into a new substance?
a. chemical change
b. physical change
c. boiling
d. melting

Chemical change

Explanation:

Matter changes into a new substance by changing into a chemical change. In a chemical change, the substance cannot be changed back to its previous state and a new substance is formed.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer