Answer:
The freezing point will be
Explanation:
The depression in freezing point is a colligative property.
It is related to molality as:
Where
Kf=
the molality is calculated as:
Depression in freezing point =
The new freezing point =
The lab question is “Based on a substance’s properties, how can you determine whether its bonds are ionic or covalent?” Fill in
2 answers:
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Answer:- 0.138 M
Solution:- The buffer pH is calculated using Handerson equation:
acts as a weak acid and
as a base which is pretty conjugate base of the weak acid we have.
The acid hase two protons(hydrogen) where as the base has only one proton. So, we could write the equation as:
Phosphoric acid gives protons in three steps. So, the above equation is the second step as the acid has only two protons and the base has one proton.
So, we will use the second pKa value. The acid concentration is given as 0.10 M and we are asked to calculate the concentration of the base to make a buffer of exactly pH 7.00.
Let's plug in the values in the equation:
Taking antilog:
On cross multiply:
[base] = 1.38(0.10)
[base] = 0.138
So, the concentration of the base that is required to make the buffer is 0.138M.
Answer: 35.72 % of Barium ions will be present in the original unknown compound.
Explanation: The reaction of Barium ions and sodium sulfate is:
Here, Sodium sulfate is present in excess, Barium ions are the limiting reagent because it limits the formation of product.
Now, 1 mole of barium sulfate is produced by 1 mole of Barium ions.
Molar mass of Barium sulfate = 233.38 g/mol
Molar mass of Barium ions = 137.327 g/mol
233.38 g/mol of barium sulfate will be produced by 137.323 g/mol of Barium ions, so
0.4105 grams of barium sulfate will be produced by = of Barium ions
Mass of barium ions = 0.2415 grams
To calculate percentage by mass, we use the formula:
Mass of the solution = 0.6760 grams
Putting the value in above equation, we get
% mass of Barium ions = 35.72%.