The decomposition of in solution in carbon tetrachloride is a first-order reaction: The rate constant at a given temperature is found to be . If the initial concentration of is 0.200 M, what is its concentration after exactly 10 minutes have passed?

see below

Explanation:

The rate constant is missing in question, but use C(final) = C(initial)e^-kt = 0.200M(e^-k·10). Fill in k and compute => remaining concentration of reactant

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