Question

ACTIVITY: SOLUTION CONCENTRATION VS. CONDUCTIVITY

A chemistry student carried out an experiment with a conducting apparatus (ammeter) similar to the one below. This ammeter measured in milliamperes (mA). The following data was taken.

Solution Reading
0.1 M H2SO4 150 mA
0.1 M Ba(OH)2 150 mA
To 30 mL of the Ba(OH)2 solution, 10 mL portions of H2SO4 were added until a total of 50 mL of H2SO4 were used. The following results were recorded.

DATA TABLE

Total H2SO4 Added Meter Reading Observations
0 mL 150 mA Ba(OH)2 and H2SO4 clear, colorless
10 mL 65 mA milky white precipitate forms
20 mL 31 mA more precipitate forms
30 mL 0 mA precipitate heavy and settles
40 mL 29 mA no added precipitate seen to form
50 mL 62 mA no change seen
How does this evidence indicate that the reaction has occurred between ions? Please Help with questions 3 and 4.

Answer 1

Does the conductivity increase or decrease?
Does the number of ions in solution increase, decrease, or remain constant?
What is the indicator of the number of ions in solution?

Answer 2

Why does it conduct more before and after this minimum point? Please Help

Answer 3

Q1. Form your double replacement equation

\(Ba\left(OH\right)_{2}\ +\ H_{2}SO_{4}\left(aq\right)\ →\ Ba_{2}SO_{4}\left(s\right)+H_{2}O(l)\)

Note: this is unbalanced
Ba2SO4 is insoluble because sulfate is only soluble with NH4+ and IA metals. Thus a precipitate of Ba2SO4 forms. This is a precipitation rxn, and yes a reaction has occurred.
[H+] and [OH-] would remain the same to form H2O, but [Ba+] and [SO4 2-] would decrease.

Q2. Conductivity will decrease because as more precipitate forms, the Ba+ and SO4 2- ions don't dissociate, and in order to be an electrolyte, the ions must dissociate.

Q3. sORRY not sure, I think it's just the mA

Q4. Sorry I'm not sure

Answer 4

Thank you justjm so much :)

Answer 5

np, I think @Vocaloid might assist you better

Answer 6

Ok, thank you

Answer 7

Actually justjm is better

Answer 8

assistance

Answer 9

Ok, I honestly just need help with the last two questions which are
Does the number of ions in solution increase, decrease, or remain constant?
What is the indicator of the number of ions in solution?
Why does it conduct more before and after this minimum point?

Answer 10

I can't answer

Answer 11

It's ok :)

Answer 12

Good luck.

Answer 13

Thank you :)

Answer 14

didn't see the table actually, I can answer 2
Does the number of ions in solution increase, decrease, or remain constant?

It increases after 30 mL of H2SO4 is added bc no precipitate is showing up and mA increases based on the table.

What is the indicator of the number of ions in solution? It's mA.


Why does it conduct more before and after this minimum point? --> this I do not know, sorry.

Answer 15

It's ok, I do appreciate the help though.