2.3 How Much? Flashcards
(19 cards)
Isotopes
Atoms of the same element which have different numbers of neutrons.
Avogadro’s number?
6 x 10 ^23
The number of atoms in one mole
Ar
Relative atomic mass
Mr
Relative formula mass
One mole
The relative atomic mass or relative formula mass of any substance expressed in grams.
Mass (g) =
Moles x Mr/Ar
Percentage yield=
Amount of product produced/ maximum amount of product possible x 100
How can food be preserved?
By adding chemicals or additives or salts.
Freezing or cooling.
Keeping it in an inner environment (e.g air tight).
Dry foods.
Food additive
A substance added to food to extend its shelf life and to improve taste/appearance.
E number
The number an additive is given in Europe. The no. is part of the European coding system for additives, shows they have been approved.
Thin layer chromatography
A method of separating the colours in a substance e.g pen ink. The process is carried out on a thin sheet of white silica paper.
Silica
Stationary phase
Solvent
Mobile phase
Factors which affect how fast a dye will travel up the silica?
How soluble the pigments are in the solvent. (the more soluble, the faster they will travel)
How strong the pigments attraction to the silica is. ( stronger attraction to silica will cause dye to move slower.)
Rf value
Distance moved by substance/distance moved by solvent
What can the mass spectrometer be used to find?
The relative molecular mass of a compound from its ion peak.
What is the molecular ion peak?
The peak with the largest mass corresponds to an ion with just one electron removed, it is always found as the last peak on the right as you look at the mass spectrum.
yield of a reaction
Amount of product that a chemical reaction produces.
Percentage yield
Tells us the amount of product that the reaction really produces with the maximum amount that could possibly be produced.
