Formulae, Equations and Amounts of Substance Flashcards
Equation for calculating RAM:
RAM = Mass/Moles
Equation for calculating number of particles in a sample:
No. particles = Amount in moles x Avagadro Constant
What is the value of the Avagadro Constant?
6.02x10^23 mol^1
What is the SI unit for amount of substance?
The mole (mol).
How do you work out empirical formulae of a compound?
work out the number of moles that are in that analysis of each element then work out the ratio of these moles to each other.
What is empirical formula?
The simplest whole number ratio of atoms in a compound.
What can Easy Moles R Magic be used to find?
The unknown mass in a reaction>
The E in Easy stands for what?
Balanced symbol equation.
The M in Moles stands for what?
Calculate the number of moles of the known substance.
What does the R stand for?
Use the balanced symbol equation to find the reacting ratio.
What does the M in Magic stand for?
Magic! Use the reacting ratio to calculate the moles of unknown substance, then use its RFM and moles to find its mass.
The volume of a sample of gas depends on what three things?
The temperature, T.
The pressure, p.
The amount of gas in moles, n.
An “ideal gas” does what perfectly?
Obeys the gas laws.
Gases that behave like ideal gases in lab conditions have what kind of boiling points?
Boiling points well below room temperature.
Ideal gas equation:
pV=nRT
Where: p is pressure in Pa V is volume in m^3 n is amount of substance in mol R is ideal gas constant in Jmol^-1K^-1 t is temperature in K
What is the value of the idea gas constant?
8.31 Jmol^-1K^-1
The ideal gas equation shows that at a fixed temperature and pressure the volume of gas only depends on what?
The amount of the gas in moles.
One mole of gas occupies how much space at room temperature?
24dm^3
Concentration of solution is what?
How much solute is dissolved in a certain volume of solvent.
Concentration of solution is measured in what?
moldm^-3
What is yield?
Yield is the amount of product you get in a chemical reaction.
What is percentage yield?
The actual yield divided by the theoretical yield multiplied by 100.
What is atom economy?
Atom economy is the percentage of desired product that ends up in the final products.
How is atom economy calculated?
Molar mass of desired product divided by sum of molar masses of all products multiplied by 100.
To use the idea gas equation pressure must be in what unit?
Pa, pascals.
100kPa is how many Pa?
100000 Pa.
To use the idea gas equation volume must be in what unit?
m^3, metres cubed.
To use the ideal gas equation amount of substance must be in what unit?
mol, moles.
What is the unit for the ideal gas constant?
Jmol^-1K^-1, joules per mole per kelvin.
In order to use the ideal gas equation temperature must be measured in what?
K, Kelvin.
What value must you add to convert Celsius to Kelvin?
273
What is 1 atm in Pa?
101,325 Pa
What is room temperature quoted as in K.
298 K.
An anion is what?
A negatively charged ion.
Test for halide ions:
Add silver nitrate to halide and a precipitate is produced.
Silver chloride is white.
Silver bromide is cream.
Silver iodide is yellow.
Test for sulphate ions:
Add HCl to react with carbonate impurities first.
Add a barium salt (soluble) and a white precipitate (barium sulphate) forms.
Oxidation is…
…loss of electrons.
Reduction is…
…gaining electrons.
What happens to a reducing agent?
It gets oxidised.
What happens to an oxidising agent?
It gets reduced.
