calculations Flashcards
What is atomic number?
The number of protons in the nucleus of an atom.
What is an electron?
A negatively charged particle that orbits the nucleus at fixed energy levels.
What is the relative mass of an electron?
1/1836.
What is relative atomic mass?
The weighted mean mass of an atom compared with 1/12th mass of a carbon atom.
What is relative isotopic mass?
The mass of an atom of an isotope compared with 1/12 mass of an atom of carbon-12.
What is relative formula mass?
weighted mean mass of a formula unit compared to 1/12 the mass of a carbon -12 atom
What is relative molecular mass?
the weighted mean mass of a molecule compared to 1/12 mass of a carbon -12 atom
What is the charge of carbonate?
CO3. 2-
What is the charge of hydroxide?
OH. 1-
What is the charge of nitrate?
NO3. 1-
What is the charge of sulfate?
SO4. 2-
What is the charge of zinc ion?
Zn. 2+
What is the amount of substances?
The quantity that has moles in its units, used as a way of counting atoms.
How can the amount of substances be calculated?
Using mass (n=m/M) or volume concentration (n=CV).
What does anhydrous mean?
A crystalline compound containing no water.
What is atom economy?
A measure of the amount of starting materials that ends up as useful products.
Why is a high atom economy good?
It means that a process is sustainable and less waste is produced.
What is the formula for % atom economy?
% atom E = (mass of desired/ sum of all reactants masses) x100.
What is an empirical formula?
The simplest whole number ratio of atoms of each element present in a compound.
What does hydrated mean?
A crystalline compound that contains water.
What is an ideal gas?
A gas which has molecules that occupy negligible space with no interactions between them.
What is the ideal gas equation?
pV = nRT.
What is a mole?
The amount of any substance containing as many particles as there are carbon atoms in exactly 12g of carbon-12 isotope.
What is percentage yield?
The percentage ratio of the actual yield of products from a reaction compared with the theoretical yield.
What does Avogadro’s constant represent?
The number of atoms per mole of the carbon-12 atom.
What is the mass formula?
mass = n x Mr.
What is Avogadro’s law?
Under the same temperature and pressure, one mole of any gas would occupy the same volume.
What is the ideal gas equation in terms of pressure and volume?
Pressure (Pa) x volume (m3) = moles (n) x gas constant (8.314 J mol-1) x temp (K).
What is the concentration equation?
n = cV.
What is molar mass?
Mass of 1 mole of substance.
What is the symbol for molar mass?
M.
What is the unit for molar mass?
g/mol.
What does atom economy indicate?
How much of the mass of the reactants is converted into useful products.
What is the % atom economy formula?
Not provided.
What is meant by the term standard solution?
A solution of known concentration.
work out the empirical formula of sodium oxide given that 0.69g of sodium combines with 0.24g oxygen
Na2O
