Physics - Moles

OCR A-Level Physics 2022

Created: November 08, 2021 | Read markdown | About these notes | View in context | Study these flashcards |

Flashcards

Avogadro’s constant and the mole

What does Avogadro’s constant represent?

avogadro-constant-represents

The number of atoms in $12$ grams of Carbon-12.

What is one mole of a substance?

mole-definition

An amount in which the number of atoms/molecules is equal to Avogadro’s constant.

What is the molar mass of a substance?

molar-mass-definition

The mass per mole of a substance.

Nucleons and mass number

How do you find the mass of one atom from its mass number/nucleon number?

mass-of-one-atom-from-mass-number

Divide the mass number by Avogadro’s constant.

What is a nucleon?

nucleon-definition

A proton or a neutron.

What is the mass number?

mass-number-definition

The number of protons or neutrons in the atom.

\[^{35} _ {17} Cl\]

Which number is the mass/nucleon number?

identifying-mass-number-in-notation
\[35\]

Counting particles

How can you calculate the number of particles from the number of moles of a substance?

particles-from-moles
\[\text{number of moles} \times \text{Avogadro's constant}\]

What is the molecular mass of a substance?

molecular-mass-definition

The mass of one molecule/atom of that substance.

What is the value of Avogadro’s constant?

avogadro-constant-value
\[6.02 \times 10^{23}\]

How many atoms are there in one mole of $^{12}C$?

atoms-in-mole-carbon-12
\[6.02 \times 10^{23}\]

How many atoms are there in one mole of $^{35}Cl$?

atoms-in-mole-chlorine-35
\[6.02 \times 10^{23}\]

How many grams are there in one mole of $^{12}C$?

grams-in-mole-carbon-12
\[12g\]

How many grams are there in one mole of $^{35}Cl$?

grams-in-mole-chlorine-35
\[35g\]

Relating N, n, m and M

What is $N$ (the number of atoms/molecules) in terms of $n$ (the number of moles) and $N _ a$ (Avogadro’s constant)?

number-of-particles-formula
\[N = n \times N _ A\]

What is $m$ (the mass of a substance) in terms of $n$ (the number of moles) and $M$ (the molar mass)?

mass-from-moles-formula
\[m = n \times M\]


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