Top Posters
Since Sunday
a
5
k
5
c
5
B
5
l
5
C
4
s
4
a
4
t
4
i
4
r
4
r
4
Home Q & A Board Science-Related Homework Help Chemistry (Moderator: Laser_3)
New Topic  
Juicy Juicy
wrote...
Go to Answer
Posts: 37
Rep: 0 0
11 years ago
I was doing my homework and got stuck on this question:

A solution of ethanol (C2H5OH) in water is prepared by dissolving 75 mL of ethanol (density = 0.79 g/cm^3) in enough water to make 250 mL of solution. What is the molarity of the ethanol in this solution?

How do you solve this problem? I need to understand this.
Read 678 times
3 Replies
Replies
wrote...
#1
11 years ago
The molarity M is defined as the amount ("number of moles") n of the solute divided by the volume V of the solution.

M = n / V

You get the amount n in two steps. First, you calculate the mass of ethanol from the given volume (75 mL) using the density. Then, you calculate the amount of ethanol n ("number of moles") from the mass and the molar mass, which you can determine from the chemical formula.

I'm assuming you don't want me to do the math, as you asked how the problem is solved rather than what the answer is.
Answer accepted by topic starter
tommynkelltommynkell
wrote...
#2
Posts: 106
Rep: 0 0
11 years ago
Sign in or Sign up in seconds to unlock everything for free
This verified answer contains over 270 words.
1

Related Topics

wrote...
#3
4 years ago
Thank you!
New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  1383 People Browsing
 106 Signed Up Today
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Live Chat
Related Images
  
 204
  
 86
  
 144
Your Opinion
Previous poll results: What's your favorite coffee beverage?