1.2 - Amount Of Substance Flashcards
What is the symbol for amount of substance?
n
What is the unit used to measure amount of substance?
Moles
What does Avogadro’s constant represent?
The number of atoms per mole of the carbon-12 isotope
How do you calculate the mass of one mole of the element?
Mass of one mole = relative atomic mass in grams
How do you calculate moles when Masaan molar mass are given?
Moles = mass / by molar mass
State Avogadro’s law
Under the same temperature and pressure, only one mole of any gas would occupy the same volume
How much volume does a gas occupy at room temperature and pressure?
24 dm^3
Define molar gas volume
The volume per mole of gas molecules
Why do different gas particles occupy the same volume?
The gas particles spread out, hence individual differences has no effect
How to calculate moles when giving gas volume
Moles = volume / 24
What are the idea ways in which gas behaves?
They are in continuous motion.
no intermolecular forces experienced
exert pressure when they collide with each other or container.
No kinetic energy is lost in the collisions
when temperature increases kinetic energy of gases also increases.
What is the ideal gas equation and what does each part mean?
pV= nRT
p = pressure (Pa)
V = volume (m^3)
n = number of moles (mol)
R = gas constant (j mol^-1)
T = temperature (K)
One atmospheric pressure is equal to how many Pascal
101325 Pa
What does concentration of a solution mean?
It is the amount of solute dissolved in 1 dm^3 of solvent
How do you calculate moles when concentration and volume are given?
n=cv
What is a standard solution?
A solution of known concentration
What is the time concentrated and dilute mean?
Concentrated - large amount of solute per dm^3 of solvent
Dilute - small amount of solute per dm^3 of solvent
What is a species in a chemical reaction?
Any particle that takes place in a reaction
What are the four common state symbols?
Solid (s)
liquid (l)
gaseous (g)
aqueous (aq)
What does percentage yield mean?
Deficiency of which reactants are converted into products
State a reason for not obtaining 100% yield
Reactions may be at equilibrium
The reactants may be impure
Side reactions could happen
Reactants or products may be left behind while transferring
Loss of products during separation and purification
How is percentage yield calculated?
Percentage yield = actual amount of product / theoretical amount of product x 100
What does atom economy tell us about?
The proportion of desired product, compared with all the products formed in the reaction
How is atom economy calculated?
Atom economy = molecular mass of desired product / sum of the molecular mass of all products x 100
Does 100% yield mean 100% atom economy?
No, even if all the reactants are converted into products, not all products of the reaction will be the required products
Which type of reaction has 100% atom economy?
Addition reactions
