Answer:
b) The dehydrated sample absorbed moisture after heating
Explanation:
a) Strong initial heating caused some of the hydrate sample to splatter out.
This will result in a higher percent of water than the real one, because you assume in the calculation that the splattered sample was only water (which in not true).
b) The dehydrated sample absorbed moisture after heating.
Usually inorganic salts may absorbed moisture from the atmosphere so this will explain the 13% difference between calculated water percent the real content of water in the hydrate.
c) The amount of the hydrate sample used was too small.
It will create some errors but they do not create a difference of 13% difference as stated in the problem.
d) The crucible was not heated to constant mass before use.
Here the error is small.
e) Excess heating caused the dehydrated sample to decompose.
Usually the inorganic compounds are stable in the temperature range of this kind of experiments. If you have an organic compound which retain water molecules you may decompose the sample forming volatile compounds which will leave crucible so the error will be quite high.
Correct answer is dilute the solution
The new volume of a 250 Ml sample of gas at 300k and 1atm if heated to 350 k at 1 atm is 291.67 Ml
<u>calculation</u>
This is solved using the Charles law formula since the pressure is constant.
that is V1/T1 = V2/T2 where,
V1 =250 ml
T1=300 K
V2=?
T2= 350 k
by making V2 the subject of the formula by multiplying both side by T2
V2= T2V1/T1
V2= (350 K x 250 ml) / 300K =291.67 Ml