Question

Calculate the mass of each sample.

Answer 1

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