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124. A
Since the question give that number of atoms in 2g of sulphur=1g of oxygen, I think they consider the molar mass of sulphur as 32gmol^-1
Statement (1) is thus correct
Statement (2) is false.
No. of atoms in 1 mole of sulphur = 6.02x10^23
No. of atoms in 2 mole of oxygen=1.20x10^24
Statement(3) is also false. Number of occupied electron shells in sulphur is 3 while that for oxygen is 2.
119.A
2 moles of XHCO3 give 1 mol of CO2
no. of mole of CO2=0.33/44=0.0075
no. of mole of XHCO3=0.015
mass of 0.00375mol of XHCO3=1.5g
formula mass=molar mass of XHCO3=100gmol^-1
114. B
1 mol NH3 produces 1 mol NH4NO3
mass of NH4NO3= 16 tonnes
mass of NH4NO3=16x(molar mass of NH3/molar mass of NH4NO3)=16x(17/80)=3.4tonnes
(this method is for students who find it difficult to change tonnes into grams)
I can't find Q 112 & 117, where are they?
2012-05-24 16:10:30 補充：
sorry, it should be
mass of NH3=16x(molar mass of NH3/molar mass of NH4NO3)=16x(17/80)=3.4tonnes
115.A
by similar method
1mol HNO3 produce 1mol NH4NO3
mass of HNO3 needed=16x(1+14+16x3)/(14+4+14+16x3)
=12.6 tonnes
