Is this the whole question?
The cations has positive charges that are metals while the anions have negative charges that are non-metals. Upon reaction, there is an exchange in charges that are reflected in the subscripts of the atoms. In this case, compound AX2 must have a cation, A belonging to group 2 A with +2 charge and anion, X belonging to Group 7A with -1 charge. Answer is D.
On the periodic table everything to the right of the line is a non metal
Everything to the left is a metal. So the line crosses to the right is NM to left is M
1 mole of any substance has Avagadro number of molecules and it's weight is equal to its molecular weight.
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Answer 1:
Molecular weight of HNO3 = 63.01 g/mol
Therefore, 1mole of HNO3 = 63.03 g
Hence, 15.7 mole of HNO3 = 63.03 X 15.7
= 989.57 g
Thus, mass of 15.7 mole of HNO3 = 989.57 g
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Answer 2:
Molecular weight of H2O2 = 34.01 g/mol
Therefore, 1mole of H2O2 = 34.01g
Hence, 0.00104 mole of H2O2 = 34.01 X 0.00104
= 0.03537 g
Thus, mass of 0.00104 mole of H2O2 is 0.03537 g
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Answer 3:
Molecular weight of SO2 = 64.07 g/mol
Therefore, 1mole of SO2 = 64.07 g
Hence, 72.1 mmole of SO2 = 64.07 X 0.0721
= 4.619 g
Thus, mass of 72.1 mm of SO2 is 4.619 g
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Answer 4:
Molecular weight of XeF2 = 169.29 g/mol
Therefore, 1mole of XeF2 = 169.29 g
Hence, 1.23 mole of XeF2 = 169.29 X 1.23
= 208.23 g
Thus, mass of 1.23 mole of XeF2 is 208.23 g
