Chemistry - v/v versus w/w

posted by .

Thanks a lot:)

So just to confirm: normally for any chemical bought from manufacturer, if it is not stated, the % usually means v/v? Seems like for conc sulphuric acid, when it is stated 97% sulphuric acid, it means 97% w/w sulphuric acid?

Thank you very much.

Posted by annie on Monday, September 20, 2010 at 10:33am.

I have a bottle of 95% ethanol purchased from the manufacturer.

Normally, when it is not stated, does it mean 95% w/w ethanol?

I need to prepare 100ml of 40% v/v ethanol solution from 95% ethanol.
Please show me the calculation steps.


Chemistry -repost thank you in advance - bobpursley, Monday, September 20, 2010 at 11:01am
when not stated, 95% is v/v

you want to dilute the ethanol 95/45 times, or 2.111 times. THat means one part alcohol, and 1.111 parts water.

100ml/2.111=47.37 is a part.
so, 47.37 ml of 95%
52.63 ml of water.

  • Chemistry - v/v versus w/w -

    I think your conclusion is wrong. You are correct that the percent on a bottle of H2SO4 means w/w. Technically, ALL manufacturers (and problem makers) should state 95% v/v or 98% w/w (or 95% w/v) but they don't. USUALLY one means w/w if it isn't stated but USUALLY one means v/v if it is two liquids (as in 95% ethanol)(which flies in the face of the H2SO4 bottle).

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Science, Chemistry

    I have been told that to prepare 1L of 70% H2SO4 from concentrated sulphuric acid (96% with density 1.84g/ml), I should use the following equation to find out the volume of conc. acid needed (Vml). V x 1.84 x 0.96={(1000-V)+ 1.84V}0.7 …
  2. Chemistry help needed

    How do I prepare 90% formic acid from conc. formic acid (98%-100% of density 1.22g/ml)?
  3. chemistry

    If the molar mass of ASA is 180.2 g/mol, how many moles of ASA were stated by rhe manufacturer to be present in the tablet tested?
  4. Chemistry

    Why is conc. Sulphuric acid used as a drying agent?
  5. Chemistry -repost thank you in advance

    I have a bottle of 95% ethanol purchased from the manufacturer. Normally, when it is not stated, does it mean 95% w/w ethanol?
  6. Chemistry problem

    I refer to my earlier post on v/v versus w/w. I would be very grateful for any advice provided. For 95% ethanol purchased from manufacturer, we normally take it as 95%v/v. For 98% sulphuric acid, it seems like it is normally 98% w/w. …

    If 15g of Sodium Hydroxide are treated with sulphuric acid to produce sodium sulphate, how many grams of sulphuric acid are required. write the balance equation for this reaction and calculate the quantity of sulphuric acid.
  8. chemistry

    concentrated aqueous sulphuric acid is 98% sulphuric acid by mass and has a density of 1.80 g/l. Volume of acid required to make one litre of 0.1M sulphuric acid solution is
  9. Finance question

    Suppose CAPM is true. You are considering investing in an equally weighted portfolio of two stocks, A and B. The betas of these stocks to the market factor are 1.10 and 0.80, respectively. The total return volatilities of stocks A …
  10. College

    Please,i need a chemical balanced equation between diethyl ether+ conc.sulphuric acid+ glacial acetic acid

More Similar Questions