The given question is incomplete. The complete question is :
This is the chemical formula for carvone (the chemical that gives spearmint its flavor) 
: An organic chemist has determined by measurements that there are 27.3 moles of carbon in a sample of carvone. How many moles of oxygen are in the sample
Answer: 2.73 moles of oxygen are there in the sample.
Explanation:
The chemical formula of carvone is .
This means:
When 10 moles of carbon are there in carvone , 1 mole of oxygen is there in carvone
Thus for 27.3 moles of carbon in carvone , 
mole of oxygen is there in carvone.
Thus 2.73 moles of oxygen are there in the sample.
The word equation for this reaction is:
Iron + Tin nitrate → Iron nitrate + Tin
The answer should be "by convection" not by radiation.
Answer:
10.8 days (3 sig.figs.)
Explanation:
All radioactive decay is 1st order decay defined by the expression A = A₀e^-kt
which is solved for time of decay (t) => t = ln(A/A₀) / -k
A = final weight = 1.0 gram
A₀ = initial weight = 16.0 grams
k = rate constant = 0.693/t(1/2) = 0.693/2.69 days = 0.258 days⁻¹
t = ln(1/16) / -0.258da⁻¹ = (-2.77/-0.258) days = 10.74646792 days (calculator)
≅ 10 days (1 sig. fig. based on given 1 gram mass)
