atoms Flashcards
% Of Abundance
chlorine occurs as a mixture of 2 isotopes CL-35 and CL-37. The R.A.M of CL is 35.5. Calculate the percentage abundance of CL-37.
Make a line showing the space between CL-35 and CL-37 and mark where the R.A.M would appear. As we are doing the percentage of CL -37 we see how much CL-37 has “tugged”. It has “tugged” the chlorine 0.5 away from CL-35 out of the 2 difference between them. To calculate % you do (how much it has tugged/gap between the chlorines) x 100.
acid + metal = salt + hydrogen
acid + metal carbonate = salt + water + carbon dioxide
molecular formulae
calculate % mass of elements in a compound
% mass of carbon 75%
% mass of hydrogen 25%
mass - 75 25
mr- 12 1
moles- 6.25 25
ratio- 1 4
ef - CH4
water crystallisation
a student heated 4.38 of hydrated zinc sulphate and obtained 2.46 of anhydrous zinc sulphate use this data to calculate x in ZnSO4.xH2O
ionic compound water
mass 2.46. 1.92
moles 0.0152 0.107
ratio 1 7
how to calculate RAM(Ar)
Ar = (isotopic mass1 X abundance1) + (isotopic mass2 X abundance 2)/total abundance
Ideal gas law
only at RTP
Number of moles = volume given / Vm (24dm)
K (Kelvin)
K = c+273
PV = NRT
P - pressure(1Kpa)
V - volume (1dm)
N - number of moles
R - the gas constant (8.314)
T - temperature(K)
55dm^3 of ethane is composted with 400dm^3 of O2 what is the total volume of gas left at the end of reaction?
2C2H6 + 7O2 == 4CO2 + 6H20
2C2H6 + 7O2 == 4CO2 + 6H20
Vol at start 55 400
-55 -7/2 x55
change 0. 207.5 55x2 55X3
vol at end 0. 207.5 110. 165
Balancing equation using masses
8.1g of zinc oxide (2ZNO) reacts completely with 0.6g of carbon to form 2.2 g of carbon dioxide and 6.5g of zinc.Write a balanced symbol equation for this.
Equation ZnO + C = CO2 + N
Mass given8.1 0.6 2.2 6.5
find mr 81 12 44 65
moles .1 .05 .05 .1
/by smallest 2 1 1 2
