## Review Worksheet [ENDORSED]

Marina Souliman 1K
Posts: 30
Joined: Fri Apr 06, 2018 11:05 am

### Review Worksheet

Can someone explain the steps to solving this problem?

Wine is approximately 12% ethanol (CH3CH2OH) by volume. Ethanol has a molar mass of 46.06 g/mol and a density of .789 g/mL. How many moles of ethanol are present in a 750 mL bottle of wine?

Susu Le 1F
Posts: 30
Joined: Thu Feb 01, 2018 3:01 am
Been upvoted: 1 time

### Re: Review Worksheet  [ENDORSED]

1) Multiply 12% by 750 mL of wine. This is the volume of ethanol (mL).
2) Use the volume of ethanol (mL) to find the mass of ethanol (g) by using the density (.789 g/mL). Now you have the mass (g).
3) Divide the mass by the molar mass of ethanol (46.06 g/mol) to find the moles of ethanol.

Emma Leshan 1B
Posts: 30
Joined: Fri Apr 06, 2018 11:03 am

### Re: Review Worksheet

I also find it very helpful to use unit conversions aka dimensional analysis to solve problems like this.

For example, you know 0.12*750mL will give you the volume in mL. Now you want to find the mass in grams, so you need the units to be g/mL in order for mL to cancel, and you'll be left with grams. Continue this method to find the moles.

I find this method to be very helpful if I'm stuck. I just think of the units I have and how I can get to the units I need.

Alicia Beebe
Posts: 37
Joined: Fri Apr 06, 2018 11:01 am

### Re: Review Worksheet

I used a different method, but wanted to see if I got the same answer. I got 1.541 mol ethanol, did anyone get the same thing or am I off track?