Answer:
Mine is doing good since I dont have any school today it makes it better. Im listening to scary stories on YT right now which always makes my day better so Im having a really good day today!
What about you? Why isn't your day doing so great?
<h3>
Answer:</h3>
28.52 seconds
<h3>
Explanation:</h3>
Initial number of atoms of Nitrogen 12,000 atoms
Half-life = 7.13
Number of atoms after decay = 750 atoms
We are required to determine the time taken for the decay.
Note that half life is the time taken for a radioactive isotope to decay to a half of its original amount.
Using the formula;
Remaining amount = Initial amount × (1/2)^n , where n is the number of half lives
In our case;
750 atoms = 12,000 atoms × (1/2)^n
0.0625 = 0.5^n
n = log 0.0625 ÷ log 0.5
n = 4
But, 1 half life =7.13 seconds
Therefore;
Time taken = 7.13 seconds × 4
= 28.52 seconds
Therefore, the time taken for 12,000 atoms of nitrogen to decay to 750 atoms is 28.52 seconds
Answer: There are 
atoms of hydrogen are present in 40g of urea, 
.
Explanation:
Given: Mass of urea = 40 g
Number of moles is the mass of substance divided by its molar mass.
First, moles of urea (molar mass = 60 g/mol) are calculated as follows.
According to the mole concept, 1 mole of every substance contains 
atoms.
So, the number of atoms present in 0.67 moles are as follows.
In a molecule of urea there are 4 hydrogen atoms. Hence, number of hydrogen atoms present in 40 g of urea is as follows.
Thus, we can conclude that there are atoms of hydrogen are present in 40g of urea, .
Answer:
1984
Explanation:
Given the formula;
0.693/t1/2 = 2.303/t log (Ao/A)
Where;
t1/2 = half life of the radioactive isotope
t= age of the wine
Ao= initial activity of the wine
A= activity of the at time = t
0.693/12.3 = 2.303/t log (5.5/0.688)
0.693/12.3 = 2.079/t
0.056 = 2.079/t
t= 2.079/0.056
t= 37 years
The wine was produced 37 years ago which means that it was produced in the year 1984
