# Use molar mass of D2O to calculate the density of heavywater

• Cory522
In summary, the conversation discusses the calculation of density from molar mass for non-gaseous substances. It also brings up the question of the effect of extra protons and neutrons on the size and interaction between molecules.

## Homework Statement

how can you go from molar mass to density if its not a gas

## Homework Equations

molar mass = 20.0276 g/mol

## The Attempt at a Solution

none

Hi Cory, welcome to PF!

Compare the number of D2O molecules in unit volume to that of water. Do the extra protonsEdit: neutrons change the size and interaction between the molecules appreciably with respect to H2O?

Last edited:
ehild said:
Hi Cory, welcome to PF!

Compare the number of D2O molecules in unit volume to that of water. Do the extra protons change the size and interaction between the molecules appreciably with respect to H2O?
It's not extra protons in D2O, it's extra neutrons.

Could you please explaing the problem once again, Cory? What exactly needs to be calculated?

SteamKing said:
It's not extra protons in D2O, it's extra neutrons.
Of course, a great typo! Thanks. :)

## 1. What is the molar mass of D2O?

The molar mass of D2O, also known as heavy water, is 20.027 g/mol. This means that one mole of D2O molecules weighs 20.027 grams.

## 2. How do I calculate the density of heavy water using its molar mass?

To calculate the density of heavy water using its molar mass, you can use the formula d = m/M, where d is the density, m is the mass in grams, and M is the molar mass in g/mol. Simply plug in the mass of heavy water and its molar mass, and you will get the density in g/mL.

## 3. Why is the molar mass of D2O important in calculating its density?

The molar mass of D2O is important in calculating its density because it is used to convert between the mass of a substance and the number of moles. In order to calculate the density, we need to know the mass of the substance, which is measured in grams, and the number of moles, which is measured in moles. The molar mass allows us to convert between these two units.

## 4. What is the density of heavy water if I know its molar mass is 20.027 g/mol?

The density of heavy water can vary depending on temperature and pressure. However, at standard temperature and pressure (STP), the density of heavy water is approximately 1.107 g/mL when its molar mass is 20.027 g/mol.

## 5. Can I use the molar mass of heavy water to calculate its density at any temperature or pressure?

No, the molar mass of heavy water is constant, but its density can change with temperature and pressure. To accurately calculate the density at a specific temperature and pressure, you will need to use the ideal gas law or another equation that takes into account these variables.

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