inorganic and physical chemistry Flashcards
(43 cards)
how do you write ionic equations
- balance the equation
- separate the soluble compounds into ions
- leave insoluble compounds as they are
- balance the charges on each side and balance the number of atoms
inc state symbols
what are the common ionic equations
- acid + hydroxide –> water
- acid + carbonate –> water + carbon dioxide
- acid + hydrogen carbonate –> water + carbon dioxide
- acid + ammonia –> ammonium
what is the relative mass of an electron
1/1836
define an atom
the smallest particle of a chemical element that can exist
define an element
a substance that contains only 1 type of atom, which all have the same number of protons
define relative atomic mass
the weighted mean mass of one atom of an element relative to 1/12 of the mass of carbon-12.
- it is an average of all the mass numbers of all the different isotopes of that element
how does a time of flight spectrometer work
- place the sample in the spectrometer
- sample is then vaporised and then ionised to form positive ions
- ions are accelerated (heavier ions move slower and are harder to deflect than lighter ones, this separates ions of each isotope)
- the ions are detected on a mass spectrum as an m/z ratio ( mass to charge) each ion that reaches the detector adds to the signal, therefore the greater the abundance, the larger the signal
define a compound
a substance composed of 2/more separate elements
define a molecule
a group of atoms bonded together representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
what are polyatom ions
gain or lose elemental ions such as a proton
what is molar mass
mass per mole of a substance in gmol-1
what is an empirical formula
simplest whole number ratio of atoms of each element in a compound
how do you calculate empirical formula
- what’s the mass??
- no. moles
- divide each no. moles by the smallest mole value to get a ratio
- adjust the numbers to make them a whole number
- write the empirical formula
what is ‘water of crystallisation’
water molecules that are bonded into a crystalline structure of a compound
define hydrated
crystallised compound containing water molecules
define anhydrous
contains no waters of crystallisation
what does ‘SnCl4 . 8H2O’ mean
8 H2O molecules per 1 SnCl4
when completing the crystallization practical, why could your value be lower
all the water was not lost so less water was released
when completing the crystallization practical, why could your value be higher
salt begins to decompose so more mass lost
how can you work out the new concentration of something
(o.g vol/new vol)* o.g conc
what is avogadro’s law
equal volumes of gases under the same temp and pressure contain the same number of molecules , therefore 1 mole of any gas occupies the same vol. at a certain temp and pressure
what is room pressure
1 atmosphere = 101 Pa
what is room temperature
25 Celsius = 298 kelvin
1 kelvin = 1 degree Celsius
what is the ideal gas equation
pV=nRT
p = pressure (Pa)
V = volume (m^3)
n = number of moles
R = gas constant (K-1mol-1)
T = temperature (K)
