Answer: The possible molecular formula will be 
Explanation:
Mass of C= 27.3 g
Mass of O = 72.7 g
Step 1 : convert given masses into moles.
Moles of C =
Moles of O =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C = 
For O =
The ratio of C : O = 1: 2
Hence the empirical formula is
The possible molecular formula will be=
With a physical change you can actually see it change like ice turning into water, then with a chemical change you can't see it change, although within the molecules themselves they change which makes that possible.
Hope this helps!
Answer:
it is 1,4
Explanation:
Just took the test hope you get it right. c:
Answer:
Two half lives.
Explanation:
It is known that the decay of isotopes and radioactive material obeys first order kinetics.
Also, it is clear that in first order decay the half-life time is independent of the initial concentration.
That means for a sample 100% to decay to 50 % it will take one half-life, and to decay the remaining 50% to 25% it will take another half-life.
So, for a sample has 25% parent and 75% daughter it will have two half-lives.
