[hellothere]

Hi,

These are some questions I had trouble with from my homework. It would be great if someone could explain them to me.

1. Which of the following solid compounds is NOT appreciably soluble in water but IS soluble in dilute hydrochloric acid?
a) Mg(OH)₂
b) (NH₄)₂CO₃
c) CuSO₄
d) (NH₄)₂SO₄
e) Sr(NO₃)₂

The answer is A, but I don't quite get it. I realize this has to do with solubility rules, but how do I distinguish what is soluble in water and what is in HCl?

2. What is the final concentration of barium ions in solution when 100. mL of 0.10 M BaCl₂ (aq) is mized with 100. mL of 0.050 M H₂SO₄(aq)?
a) 0.00 M
b) 0.012 M
c)  0.025 M
d) 0.075 M
e) 0.10 M

I thought it would just be .1L(0.10M)= .01 mol Ba2+ and the .01mol/.2L=.050 M, but apparently the answer is C.

[Borek]

What happens to hydroxides in solutions of acids?

What happens to Ba²⁺ in the presence of sulfates?

[hellothere]

Hydroxides form water with acid? I don't quite remember, we haven't covered acids and bases yet.

and i figured out the other one

[hellothere]

I'm not sure if I'm allowed to post another question on the same forum, but I will delete if necessary.

What is the net ionic equation for the reaction that occurs when aqueous CuSO₄ is added to 6M ammonia?

I'm not sure how to do this one at all. Could it have something to do with the formation of complex  ions?

A white solid is observed to be insoluble in water, insoluble in excess ammonia solution and soluble in dilute HCl. Which of the following compounds could the solid be?
a) CaCO₃
b) BaSO₄
c) Pb(NO₃)₂
d) AgCl
e) Zn(OH)₂

A is the answer. I don't know how to go about with this problem either :/

[vhpk]

I'm not sure if I'm allowed to post another question on the same forum, but I will delete if necessary.

What is the net ionic equation for the reaction that occurs when aqueous CuSO₄ is added to 6M ammonia?

I'm not sure how to do this one at all. Could it have something to do with the formation of complex  ions?

A white solid is observed to be insoluble in water, insoluble in excess ammonia solution and soluble in dilute HCl. Which of the following compounds could the solid be?
a) CaCO₃
b) BaSO₄
c) Pb(NO₃)₂
d) AgCl
e) Zn(OH)₂

A is the answer. I don't know how to go about with this problem either :/

So for this kind of question, u need to know the properties of cations and anions.
So based on the questions, can you tell me:
a/ What compound is soluble in water ?
b/ What compound is insoluble in excess NH₃,i.e. no reaction with NH₃ occurs?
c/ What compound can react with dilute HCl?
Then it's easy for the answer