# Finding molarity of substance

• alingy1
In summary, the conversation is discussing how to calculate the molarity of glacial acetic acid, which has a density of 1.05g/ml and is 99.51% acetic acid by mass. The conversation also touches on the definition of molarity and clarifies that it is the moles of the constituent (CH3COOH) divided by the liters of solution. It is confirmed that only the moles of acetic acid are used when calculating molarity, not the total number of moles.
alingy1

## Homework Statement

Glacial acetic acid has a density of 1.05g/ml and contains 99.51%acetic acid (CH3COOH) by mass. Calculate the molarity of glacial acetic acid.

So, this is a question in my pre-lab that doesn't even count. But, I still want to get it because we have similar questions in exams.

I'm blocked at the first step:
What is molarity?
Is is the total number of moles? or just the number of acetic acid moles?

It doesn't really help. I'm asking to know if glacial acetic acid is a solution per se. What is the small percentage that makes CH3COOH account for 99.51%? And is that substance taken into any account when you do the calculation of molarity.

alingy1 said:
It doesn't really help. I'm asking to know if glacial acetic acid is a solution per se. What is the small percentage that makes CH3COOH account for 99.51%? And is that substance taken into any account when you do the calculation of molarity.

Did you look at the definition of molarity? We aren't concerned with 0.49% but that will be used when calculating molarity. Have a look at the definition, you will get some idea to begin with.

Also, if you take a look at the definition, you can apply it even to pure water - that's a very similar situation.

Do you know how to find the number of moles of CH3COOH in 1000 mL of glacial acetic acid? That is the same as the molarity.
What is molarity?
moles of constituent (CH3COOH here)/ Liters of solution (glacial acetic acid here)
Is is the total number of moles? or just the number of acetic acid moles?
Only acetic acid.

## What is molarity?

Molarity is a measure of concentration of a substance in a solution. It is defined as the number of moles of a substance per liter of solution.

## How do you calculate molarity?

Molarity can be calculated by dividing the number of moles of a substance by the volume of the solution in liters. The formula for molarity is M = moles of solute / liters of solution.

## What are the units of molarity?

The units of molarity are moles per liter (mol/L) or sometimes written as molar (M).

## Why is molarity important in chemistry?

Molarity is important in chemistry because it is a way to accurately measure the concentration of a substance in a solution. It allows scientists to make precise and consistent measurements in experiments and to determine the amount of a substance needed for a reaction.

## How does temperature affect molarity?

Temperature can affect molarity because it can change the volume of the solution. As temperature increases, the volume of the solution also increases, resulting in a lower molarity. This is because the number of moles of a substance remains constant, but the volume changes. It is important to take temperature into consideration when calculating molarity.

• Biology and Chemistry Homework Help
Replies
2
Views
2K
• Biology and Chemistry Homework Help
Replies
2
Views
2K
• Biology and Chemistry Homework Help
Replies
2
Views
3K
• Biology and Chemistry Homework Help
Replies
7
Views
4K
• Biology and Chemistry Homework Help
Replies
7
Views
2K
• Biology and Chemistry Homework Help
Replies
5
Views
1K
• Biology and Chemistry Homework Help
Replies
4
Views
3K
• Biology and Chemistry Homework Help
Replies
1
Views
3K
• Biology and Chemistry Homework Help
Replies
4
Views
1K
• Biology and Chemistry Homework Help
Replies
8
Views
2K