# Chemistry -repost thank you in advance

posted by .

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.

Thanks.

• Chemistry -repost thank you in advance -

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.

## Similar Questions

1. ### science(chem)

I'm making different concentrations of ethanol and I just wanted to check my calculations and method. Making ethanol concentrations of: 0.40% 0.30% 0.20% 0.10% 0.05% To make the 0.40% ethanol from stock solution using 100ml volumetric …
2. ### chemistry

What is the mass/vol % ethanol in an ethanol-water solution with density of 0.875 g/ml and containing 65.0% ethanol by volume?
3. ### Chemistry- urgent help needed

How do I prepare 40% v/v from 95% ethanol?
4. ### Chemistry - v/v versus w/w

Thanks a lot:) So just to confirm: normally for any chemical bought from manufacturer, if it is not stated, the % usually means v/v?
5. ### 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. …
6. ### AP Chemistry

A bottle of wine contains 12.5% ethanol by volume. The density of ethanol (C2H5OH) is 0.789 g/cm3. Calculate the concentration of ethanol in wine in terms of mass percent and molality.
7. ### CHEMISTRY

ETHANOL (C2H5OH) HAS A DENSITY OF 0.80g/ml. IF A 10%(v/v) MIXTURE OF ETHANOL IN WATER WAS PREPARED HOW MANY GRAMS OF ETHANOL WOULD BE IN 100ML OF THE MIXTURE?
8. ### Chemistry

When doing a simple distillation of ethanol-water, is the vapor pure ethanol or does it also contain water?
9. ### Chemistry

A bottle of wine contains 11.4% ethanol by volume. The density of ethanol (C2H5OH) is 0.789 g/cm3. Calculate the concentration of ethanol in wine in terms of mass percent and molality.
10. ### Chemistry

Alcoholic drinks contain ethanol. 10cm3 of ethanol is called one unit of alcohol. Men are advised to drink a maximum of 21 units of ethanol a week, while women are advised to drink a maximum of 14 units. Wine contains about 14% ethanol …

More Similar Questions