Answer is: atomic masses.
For example, calculate molecular mass of one mole of ethanol (C₂H₅OH). Molecule of ethanol has two carbon atoms, six hydrogen atoms and one oxygen atom:
M(C₂H₅OH) = 2Ar(C) + 6Ar(H) + Ar(O) · g/mol.
M(C₂H₅OH) = 2·12 + 6·1 + 16 · g/mol.
M(C₂H₅OH) = 46 g/mol; molar mass.
Atomic mass is approximately equivalent to the number of protons and neutrons in the atom.
Hello There!
Physical changes can be reversed whereas chemical changes can not.
Rain turning to snow is a physical change.
The snow could certainly be changed back into rain.
An example of a chemical change is making toast.
Once the toast is made, it is not possible to reverse.
In short, it is a physical change.
Hope This Helps You!
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- Hannah ❤
answer
When an electron temporarily occupies an energy state greater than its ground state, it is in an excited state. An electron can become excited if it is given extra energy, such as if it absorbs a photon, or packet of light, or collides with a nearby atom or particle
Answer:
Pressure will increase by the direct ratio of the volume change. Therefore, since volume changes from 145 to 80, pressure will go up by the ratio change 145÷80 times the original pressure 125 kPa. Sure, you can use the more complicated gas law equation PV = nRT but we are only varying volume so the question boils down to the change in one simple variable.
Putting them together we have: 145÷80 x 125 = 226.5625 or just 226 kPa since the accuracy of the figures and the equation are not great.
Explanation:
A mole is the amount of matter or substance that contains the Avogadro's number of particles.
1 mole of a substance = 6.02 x 10²³ atoms
Now solving:
a:
1.2 x 10² atoms ;
Number of moles = = 2.0 x 10⁻²¹moles
b:
3.87 x 10²¹ molecule:
Number of moles = = 6.4 x 10⁻³moles
c. 4.81 x 10¹⁴ molecules:
Number of moles = = 8.0 x 10⁻¹⁰moles
Number of molecules = number of atoms = formula units
learn more:
Number of moles brainly.com/question/1841136
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