Formulae, equations and amount of substance Flashcards
what is the relative charge for protons neutrons and electrons
protonsβ> +1
neutronsβ> 0
electronsβ>-1
atomic number, mass number
what is the relative mass for protons neutrons and electrons
protonsβ>1
neutronsβ>1
electronsβ>1/2000
atomic number, mass number
what are negative charges mean for ions?
theres more electrons than protons(number + minus )β> more electrons
what do positive charges mean for ions and give an example?
positve charges meant that there is more than protons than electrons β>eg magnesium which is in group 2 has 2+ charge . Proton number/atomic is 12 therefore the electron number must be 10
what are isotopes?
elements with the same number of protons but different number of neutrons
what is relative atomic mass(Ar)?
weighted mean mass of an atom of an element compared to 1/12th of the mass of an atom of carbon 12.
relative atomic mass
what is the relative molecular mass(mr)?
weighted mean mass of a molecule compared to the mass of 1/12th of the mass an atom of carbon 12
relative molecular mass (Mr)
what is the relative isotopic mass ?
mass of a atom of an isotope compared to 1/12th of the mass of carbon 12.
relative isotopic mass
what is avogadros number for and what is the number?
avogadros number is measuring the amount of a substance and the number is 6.02x 10^23
Avogadro constant
how do you find the number of particles of a substance ?
number of particles=avogadros constant x number of moles
how can you find the number of moles?
moles= mass/mr
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how do you find moles in soloutions?
moles =concentration (moldm-3) x volume(dm^3)
do isotopes have the same chemical and physcial property and why?
isotopes have the same chemical propery because its dependent on **number/arrangement **of electrons and isotopes have the same number of electrons.
isotopes have dofferent physical properties because its dependent on mass number and isotopes hae same atomic number but different mass number.
what makes up most the mass/volume of a atom
massβ>nucleus
volumeβ> empty space
what are ionic equations?
equations that show the ions formed in a soloution and which particles are reacting
balanced full and ionic chemical equations,
including state symbols
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what are spectator ions ?
they are ions are on both sides of the ionic equations and are NOT involved in the reaction
balanced full and ionic chemical equations,
including state symbols
$$$is water an ion and why?
NOT an ion and ions are only only acids bases and salts
balanced full and ionic chemical equations,
including state symbols
how do you find the theoretical mass of a substance
-balence equation
-find mr of each species
-perform mass= moles x mr (using moles as balencing number)
-form it into a ratio and dividing each side by the smallest mass
-times each side by the given quantity
masses of substances
what is emperical formula?
the simplest ratio of elements in a compound
empirical
and molecular formulae
how do you find the emperical formula of a compound?
-substitute percentage/ value in a ratio with elements
-divide each element by the mr of each(as if moles=mass/mr)
-divide ALL answers by the smallest amount of moles
-substitute the answer to the emperical formula
empirical and molecular formula
how do you find molecular formula of a substance?
-write down and substitute percentage/masses of each compound
-divide compounds by mr as if moles=mass/mr
-see the element wanted and times or divide the answer of compound by moles/atoms
-divide the recent answers by the smallest number
-substitute back in
empirical
how do you find percentage compostition state the formula
percentage mass= total ar of desired element/mr of whole compound x100
eg Find the percentage of calcium in calcium carbonate, CaCO3.
how do you find out the value of water of crystallisation?
heat an a hydrated salt to remove water of crystallisation to form a anhydrous salt
how do you find out water of crystallistion with calculations?
-put the hydrated and anyhrated salts in a ratio
-use moles=mass/mr
-divide by the smallest answer of moles
-substitute the answeer in the compound to find x
what is the equation for percentage yield?
actual yield/theoretical yield
x100
what is theoretical yield?
amount of a product produced assuming no products have been lost AND reactants have rected fully
whats the equatuon for more concentrated soloutins?
volum use=final concentration divide by initial conc x volume reqiured
