Answer:

Explanation:
(a) Balanced equation
Cu + 2AgNO₃ ⟶ Cu(NO₃)₂+ 2Ag
(b) Calculation
You want to convert atoms of Cu to atoms of Ag.
The atomic ratio is ratio is 2 atoms Ag:1 atom Cu

I believe the ratio is 1:2
The formula C2H4 can be classified as both a molecular formula
and an empirical formula. The answer is number 4.
Mass number = number of protons + number of neutrons
number of protons = atomic number =7
number of neutrons= mass number - number of protons=16-7=9
Answer is B.9.