Chemistry Past Questions and Answers

X(g) → X\(^-\)(g). The type of energy involved in the above transformation is?

Chlorine, consisting of two isotopes of mass numbers 35 and 37, has an atomic mass of 35.5. <br/>The relative abundance of the isotope of mass number 37 is?

10.0 dm<sup style='font-size: smaller;'>3</sup> of air containing H<sub style='font-size: smaller;'>2</sub>S as an impurity was passed through a solution of Pb(NO<sub style='font-size: smaller;'>3</sub>)<sub style='font-size: smaller;'>2</sub> until all the H<sub style='font-size: smaller;'>2</sub>S had reacted. The precipitate of PbS was found to weigh 5.02 g. According to the equation: <br/>Pb(NO<sub style='font-size: smaller;'>3</sub>)<sub style='font-size: smaller;'>2</sub> + H<sub style='font-size: smaller;'>2</sub>S → PbS + 2HNO<sub style='font-size: smaller;'>3</sub> the percentage by volume of hydrogen sulphide in the air is?<br/>(Pb = 207, S = 32, GMV at s.t.p = 22.4dm<sup style='font-size: smaller;'>3</sup>)

A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T?

The solubility in moles per dm<sup style='font-size: smaller;'>3</sup> of 20g of CuSO<sub style='font-size: smaller;'>4</sub> dissolve in 100 of water at 180°C is?<br/>(Cu = 63.5, S = 32, O = 16)