Question

You are asked to write observations about a 100g sample of Nitrogen-16 before it decays, but you’re running late. In order to make observations, you require at least .5g of material. Can you make observations if you are 57 seconds late to the lab?

Answer 1

You can't make observation because the minimum mass is not reached

Further explanation

The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.  

Usually radioactive elements have an unstable atomic nucleus.  

The main particles are emitted by radioactive elements so that they generally decay are alpha (α), beta (β) and gamma (γ) particles  

General formulas used in decay:  

$\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}$

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

Nitrogen-16 has a half-life of 7.1 s, so t1/2 = 7.1 s

T=duration of decay  = 57 s

No= initial sample = 100 g

Nt expectes(at least) : 0.5 g

Amount of Nt after 57 s :

$\tt Nt=100.\dfrac{1}{2}^{57/7.1}\\\\Nt=0.383~g$

So you can't make observation(0.383 < 0.5)