chem questions

[2quik]

1- what volume of water would be needed to dilute 50mL of a 3M HCL solution to 1M?
Answer is supposed to be 100mL, But i get 150mL???

2-What volume of .5 M NaOH is needed to neutralize 25 mL of 2 M H2SO4?
Answer is 200mL ...i get 100ML???

thanks!

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[Futureortho24]

1- what volume of water would be needed to dilute 50mL of a 3M HCL solution to 1M?
Answer is supposed to be 100mL, But i get 150mL???

2-What volume of .5 M NaOH is needed to neutralize 25 mL of 2 M H2SO4?
Answer is 200mL ...i get 100ML???

thanks!

Ok for #2 since it is a neutralization rxn you cant use M1V1=M2V2, but instead you use Normality - N1V1 = N2V2. The H2SO4 has 2H's so you take the 2 and multiply it by the molar conc (2X2) which gives you 4N. Now you can do (4)(25)=(0.5)(XmL) and that gives you 200mL.......someone correct me if I am wrong!

For #1 I remember this question from somewhere but I also get 150

 

[2quik]

cool, thanks! i think #1 is just kaplan's mistake.

 

[tom_servo_dds]

1- what volume of water would be needed to dilute 50mL of a 3M HCL solution to 1M?
Answer is supposed to be 100mL, But i get 150mL???

2-What volume of .5 M NaOH is needed to neutralize 25 mL of 2 M H2SO4?
Answer is 200mL ...i get 100ML???

thanks!

Kaplan is correct. What it's asking you there is what IN ADDITION to what you already have will get you to 1M. Yes you will end up with 150mL but you will only be adding 100mL to that which is how the question was phrased. Hope this helps.

 

[Hopin']

Kaplan is correct. What it's asking you there is what IN ADDITION to what you already have will get you to 1M. Yes you will end up with 150mL but you will only be adding 100mL to that which is how the question was phrased. Hope this helps.

Perfect.....
Kaplan is right.... it is 100mL. 100mL(water) + 50mL( 3M HCL)= 150mL total volume

 

[allstardentist]

Perfect.....
Kaplan is right.... it is 100mL. 100mL(water) + 50mL( 3M HCL)= 150mL total volume

i agree too kaplan is correct