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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Bekah on November 16, 2007, 12:10:10 AM

Title: calculating moles of NaOH in 300ml of .1 NaOH & calculating volume
Post by: Bekah on November 16, 2007, 12:10:10 AM

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Two questions: Calculate the number of moles of NaOH in 300ml of .1 M NaOH.

2nd question: Calculate the volume of 3 M NaOH required to prepare 300ml of .1 M NaOH

I have a few of these types of questions and not sure how to do them. Hoping an answer to these will help me get started.

The number of moles in NaOH is: Na=23+O=16+H=1 which totals 40 moles
That is all I know how to do... 

 
       

Title: Re: calculating moles of NaOH in 300ml of .1 NaOH & calculating volume
Post by: Sev on November 16, 2007, 12:23:37 AM

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Two questions: Calculate the number of moles of NaOH in 300ml of .1 M NaOH.

If you have 0.3L, and there are 0.1moles per L, how many moles? n=cv

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2nd question: Calculate the volume of 3 M NaOH required to prepare 300ml of .1 M NaOH

How many moles in the 300mL soln (same as first question).  This amount will also be present in 3M soln.  c₁v₁ = c₂v₂: solve for v₂.

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The number of moles in NaOH is: Na=23+O=16+H=1 which totals 40 moles
That is all I know how to do... 

You have calculated the molar mass of NaOH here, which is not nessesary to solve problem.

Title: Re: calculating moles of NaOH in 300ml of .1 NaOH & calculating volume
Post by: Bekah on November 16, 2007, 01:33:12 AM

What does c & v stand for in the equation?

Title: Re: calculating moles of NaOH in 300ml of .1 NaOH & calculating volume
Post by: Sev on November 16, 2007, 01:44:11 AM

c is concentration (in moles/Litre), v is volume (in Litres), n is number of moles.