What Are the Correct Answers to These Basic Chemistry Practice Questions?

[deltabourne]

I'm really no good at Chemistry, and these are practice questions to our test tomorrow (with no answers, which is pretty worthless )

5. A 10mL solution of 1.0M NaOH is required to react completely with how many mL of a 0.25M solution of H2SO4?
a) 20mL
b) 40mL
c) 160mL
d) 4mL
e) 10mL

I think D, though I'm probably wrong.

10. A mixture of 2.00g of NaCl and enough water (H2O) to result in 100 mL of solution will have what molarity?
a) 2.00M
b) 0.034M
c) 0.058M
d) 0.34M
e) 0.58M

I don't even know where to start with this one :(

11. In which of the following name-formula pairs do both items correctly name the same compound?

a) SeCl6 - Selenium hexachloride
b) Br2O5 - Dibromide pentoxide
c) F2O7 - Fluorine septoxide
d) Ba(OH)2 - Barium dihydrate
e) P4S10 - Quatraphosphoric decasulfide

I have it narrowed down between A and B, they both seem to work, though I am leaning towards A?

20. In which of the following aqueous mixtures will no chemical reaction occur?
a) Hg(NO3)2 (aq) + Na2(SO4) (aq) ->
b) Na3(PO4) (aq) + Sr(NO3)2 (aq) ->
c) Na2CO3 (aq) + Ba(OH)2 (aq) ->
d) (NH4)2S (aq) + CaI2 (aq) ->
e) ZnSO4 (aq) + MgCl2 (aq) ->

No idea, think it's E though?

21. In the following reaction: 2HBr (aq) + Ba(OH)2 (aq) -> BaBr2(?) + 2H2O(?)
a) Ba(OH)2 is a weak base
b) H2O is a spectator ion in this reaction
c) HBr is a strong acid and Ba(OH)2 is a strong base
d) HBr is a weak acid
e) BaBr2 is insoluble and precpitates

Think it's C

That's all for the moment, thanks :/

 

[deltabourne]

what am I, a leper or something? :D

 

[ShawnD]

Just make a formula that will cancel all the units and it will work out fine. ALWAYS WRITE THE UNITS when you are doing anything in chemistry.

Originally posted by deltabourne

5. A 10mL solution of 1.0M NaOH is required to react completely with how many mL of a 0.25M solution of H2SO4?
a) 20mL
b) 40mL
c) 160mL
d) 4mL
e) 10mL

I think D, though I'm probably wrong.

I got 40mL, which is B

10. A mixture of 2.00g of NaCl and enough water (H2O) to result in 100 mL of solution will have what molarity?
a) 2.00M
b) 0.034M
c) 0.058M
d) 0.34M
e) 0.58M

I don't even know where to start with this one :(

I got 0.348M which is close to D

11. In which of the following name-formula pairs do both items correctly name the same compound?

a) SeCl6 - Selenium hexachloride
b) Br2O5 - Dibromide pentoxide
c) F2O7 - Fluorine septoxide
d) Ba(OH)2 - Barium dihydrate
e) P4S10 - Quatraphosphoric decasulfide

I have it narrowed down between A and B, they both seem to work, though I am leaning towards A?

The answer is A (or at least I think it is).

20. In which of the following aqueous mixtures will no chemical reaction occur?
a) Hg(NO3)2 (aq) + Na2(SO4) (aq) ->
b) Na3(PO4) (aq) + Sr(NO3)2 (aq) ->
c) Na2CO3 (aq) + Ba(OH)2 (aq) ->
d) (NH4)2S (aq) + CaI2 (aq) ->
e) ZnSO4 (aq) + MgCl2 (aq) ->

No idea, think it's E though?

This question I don't know. My redox table doesn't list most of those (like SO4, NO3, Sr, CO3).

21. In the following reaction: 2HBr (aq) + Ba(OH)2 (aq) -> BaBr2(?) + 2H2O(?)
a) Ba(OH)2 is a weak base
b) H2O is a spectator ion in this reaction
c) HBr is a strong acid and Ba(OH)2 is a strong base
d) HBr is a weak acid
e) BaBr2 is insoluble and precpitates

Think it's C

I too think it's C.

and yes, you are a leper

 

[himanshu121]

I got 40mL, which is B

Nope u are using molarity equation instead of normality
it should be

N₁V₁=N₂V₂
So u have 10*1=2*0,25*V₂

V₂= 10/0,5=20mL

 

[ShawnD]

Oh yeah, 2 to 1 ratio. Sorry about that. Subscripts DO make it easier to read :D

Do you know what the answer to that reaction one is?

 

[deltabourne]

ty very much, I got it.. I had my test today, I hope I did well