How many atoms of copper are in a pure copper penny that weighs 2.15 g? (1 amu = 1.6605 10-24 g)?

There are 2.04.10²² atom in a pure copper penny that weighs 2.15 g

Further explanation

Atoms are composed of 3 types of basic particles namely protons, electrons, and neutrons

The mass of this basic particle is expressed in units of atomic mass

Atomic mass is the average atomic mass of all its isotopes  

In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu  

So the atomic mass obtained is the mass of the atom relative to the 12th carbon atom  

Mass atom X = mass isotope 1 . % + mass isotope 2.%

An atomic mass unit = amu is a relative atomic mass of 1/12 the mass of an atom of carbon-12.  

The 'amu' unit has now been replaced with a unit of 'u' only  

This atomic unit uses the standard atomic mass, that is, the C-12 isotope

1 atom C-12 = 12 atomic mass units

1 atomic mass unit = 1/12 x mass 1 C-12 atom

1 unit of atomic mass = 1.66.10⁻²⁴ grams

the mass of each basic particle in atomic mass units is:

electron mass = 9.11.10⁻²⁸ grams

proton mass = 1.6726.10⁻²⁴ grams

neutron mass = 1,675.10⁻²⁴ grams

The proton mass is considered to be equal to 1 atomic mass unit and a neutron which is also considered to be equal to 1 atomic mass unit

A pure copper penny have weighs 2.15 g

And atomic mass of Copper = 63.5 amu

Then :

Mass in grams = 63.5 x 1.66.10⁻²⁴

mass in grams = 105.41 .10⁻²⁴ grams

With 2.15 grams ,

The total atoms becomes : 2.15 grams : 105.41 .10⁻²⁴

total atoms : 2.04.10²²

The subatomic particle that has the least mass  

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element 2512X  

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about subatomic particles statement  

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Keywords: mass number, atomic mass, amu, isotope