2.1 Atoms and Reactions (completed) Flashcards
2.1.1 Atomic structure and isotopes 2.1.2 Compounds, formulae and equations 2.1.3 Amount of a substance 2.1.4 Acids 2.1.5 Redox Reactions
What are isotopes?
atoms of the same element with different numbers of neutrons and different masses
What is relative atomic mass?
weighted mean mass of an atom compared to 1/12th mass of carbon-12
What are the common molecular ions you must remember?
NO 3–, CO3 2–, SO4 2–, OH–, NH4+, Zn2+ and Ag+
What is the empirical formula?
The simplest whole number ratio of atoms of each element present in a compound
What is the molecular formula?
The actual number ratio of atoms of each element present in a compound
What is the ideal gas equation?
pV=nRT p - pressure (Pa) V - volume (m^3) n - number of moles (mol) R - ideal gas constant (J/mol/K) T - temperature (K)
What is the formula of common acids you need to know?
HCl, H2SO4, HNO3 and CH3COOH
What is the formula of common alkalis you need to know?
NaOH, KOH and NH3
What is a strong acid?
An acid that completely dissociates in water
What is a weak acid?
An acid that partially dissociates in water
Acid + Base
Salt + Water
Acid + Carbonate
Salt + Water + Carbon dioxide
Acid + Metal Oxide
Salt + Water
Acid + Metal Oxide
Salt + Water
What is the oxidation number of manganese in Manganese (IV) Oxide?
+4
What is oxidation or reduction?
Oxidation increase in oxidation number or loss of electrons and vice versa
What is the oxidation number of an element?
0
What is the oxidation number of an ion?
It’s charge
When is the oxidation number of oxygen not normal?
-1 in peroxides and +2 F2O
When is the oxidation number of chlorine not normal?
+1 with flourine or oxygen
When is the oxidation number of hydrogen not normal?
-1 in metal hydrides
What is Avogadro’s Constant?
The number of atoms in one mole of a substance
What is a mole?
The amount of any substance containing as many particles as there are particles in 12g of the carbon-12 isotope.
What is the equation for the number of moles of a substance?
moles = mass / Mr
What is molecular formula?
The number of atoms of each element in a molecule
In hydrated salts, what is the name given to water molecules?
Water of crystillisation
What is the concentration of a solute?
The amount of solute (in moles) dissolved in each 1dm^3 of solution
What is the equation for finding a solution’s concentration?
Concentration = moles / volume
What is the ideal gas equation?
pV=nRT p - pressure (Pa) V - volume (m^3) n - number of moles (mol) R - ideal gas constant (J/mol/K) T - temperature (K)
What are standard conditions?
298K
100kPa or 1 atm of pressure
1.0 mol dm-3
What is percentage yield?
Actual yield
———————— x100
Theoretical yield
Why is the theoretical yield so hard to achieve?
Reaction is incomplete.
Competing side reactions giving different products.
Loss of product in handling and purification.
Reversible reaction.
What is atom economy?
Molar mass of desired products divided by the sum of the molar masses of all products, expressed as a percentage.
What are the benefits of a high atom economy?
Produce a larger proportion of desired products and few waste products.
Important for sustainability, best use of natural resources.
What is the gas and mole equation in standard conditions?
moles = volume / 24
What is water of crystalisation?
The water used to hydrate salts; to make anydrous salts you need to heat them.
e.g. CaCl2.6H2O
What is a Standard Solution?
A solution with a known concentration
What is the atomic number?
The number of protons in the nucleus of an atom
What is relative isotopic mass?
The mass of an atom compared to 1/2th of the mass of an atom of carbon-12
What is the relative molecular mass?
The weighted mean mass of a molecule compared to 1/2th of the mass of an atom of carbon-12
What is the relative formula mass?
The weighted mean mass of a formula unit compared to 1/2th of the mass of an atom of carbon-12
What state is an acid always?
Aqueous
What is an alkali?
Soluble bases that release OH- in water
What does low volatility mean?
High boiling point