Chapter 3 - Amount of Substance Flashcards
What is empirical formula?
The simplest whole-number ratio of atoms of each element in a compound.
What is the water of crystallisation?
The water molecules that are bonded in to the crystalline structure of a hydrated compound.
How can you tell that all water has been lost from a group of crystals?
When the crystals have changed colour and no longer change in mass.
Many salts decompose further when heated (e.g. copper(II) sulfate decomposes to form black copper(II) oxide when heated very strongly).
What is a standard solution?
A solution of known concentration.
What is the molar gas volume?
The volume per mole of gas molecules at a stated temperature and pressure.
What are the values of RTP?
298K and 101kPa (1 atm)
What is stoichiometry?
The ratio of the amount (moles) of each substance.
What is the limiting reagent?
The reactant that is not in excess that will be used up first and stop the reaction.
It dictates the amount of product that is produced.
It is the reactant with the smallest value of n.
What is the atom economy of a chemical reaction?
The percentage proportion of reactants that are converted into useful products.
How can you check that the water of crystallisation has been removed?
By heating to constant (unchanging) mass.
What are the 3 main equations of chapter 3?
n = m/M
n = c x V
(if V is in dm3)
pV = nRT
How do you calculate mass concentration (gmol-1)?
c / M
What are the trends in molar gas volume with increasing temperature or pressure?
Molar gas volume increases as temperature increases.
Molar gas volume decreases as pressure increases.
What is the oxidation number of oxygen when bonded to fluorine?
+2
What is the oxidation number of oxygen in a peroxide?
-1
