What is the relationship between the amu and the gram?

In summary, the textbook told me that there's a relationship between the amu and the gram, but I fail to see any. Could you please show me? Thank you.
  • #1
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The textbook told me that there's a relationship between the amu and the gram, but I fail to see any. Could you please show me? Thank you.
 
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  • #2
They are both are a measure of mass.

1 atomic mass unit = 1.66053886 × 10-27 kilograms = 1.66053886 × 10-24 grams. You can look this value up in books/online pages.

You can derive it by realizing that 1 amu is defined as 1/12th the mass of a C-12 atom.
 
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  • #3
dav2008 said:
They are both are a measure of mass.

1 atomic mass unit = 1.66053886 × 10-27 kilograms

But how is 1g of anything = 6.022 X 10^23 amu

Isn't 1 amu = 1/12 Carbon-12 so therefore 6.022 X 10^23 amu = 6.022 X 10^23 amu / 12 Carbon-12 ?

I'm quite confused. Where did chemists get 1g of anything = 6.022 X 10^23 amu. :confused:
 
  • #4
A lot of things are defined in respect to very specific situations. For example, the second is defined as "9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom". The meter is defined as "the length of the path traveled by light in absolute vacuum during a time interval of 1/299,792,458 of a second".

That doesn't mean that we are restricted to using seconds only when talking about cesium atoms, or using meters only when talking about how far light travels.

The amu is just a convenient unit to use when talking about things with mass on the scale of atoms. (And those things are typically atoms)
 
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  • #5
It's somewhat convenient, the relation between grams to amu that is, in the sense that the value in amu of a particular atom/compound is pretty much the same with the mass of a mole of that atom/compound. Thus reading up on the history of moles, and why it was created, should add some excitement to this matter, that of the relationship between the mass of an individual atom/compound with that of a sample. The whole thing was somewhat devised, that is they were seeking for such a method of gravimetric analysis, and that's why the "mole" is so special.
 

What is the relationship between the amu and the gram?

The amu, or atomic mass unit, is a unit of measurement used to express the mass of atoms and molecules. The gram is a unit of measurement for mass in the metric system. The two units are related because they both measure mass, but they have different scales and conversions.

How do you convert between amu and grams?

To convert between amu and grams, you can use the conversion factor of 1 amu = 1.66054 x 10^-24 grams. This means that to convert from amu to grams, you would multiply the number of amu by 1.66054 x 10^-24. To convert from grams to amu, you would divide the number of grams by the same conversion factor.

Why do we use the amu and gram units separately?

The amu is used to measure the mass of individual atoms and molecules, while the gram is used to measure the mass of larger objects. This separation allows for more precise measurements when dealing with extremely small particles like atoms and molecules.

How are the amu and gram related to the atomic mass and molar mass?

The atomic mass of an element is the total mass of the protons, neutrons, and electrons in an average atom of that element, expressed in amu. The molar mass of a substance is the mass of one mole of that substance, expressed in grams. Therefore, the amu and gram units are related to atomic mass and molar mass, respectively.

Is there a difference in the relationship between amu and gram for different elements?

Yes, the relationship between amu and gram may vary for different elements because the atomic mass of an element is specific to that element. For example, the atomic mass of carbon is 12 amu, which is equivalent to 12 grams. However, the atomic mass of oxygen is 16 amu, which is equivalent to 16 grams. Therefore, the conversion factor between amu and grams will be different for each element.

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