Chemistry Past Questions and Answers

An atom ²³⁸₉₂X decays by alpha particle emission to give an atom Y. The atomic number and mass number of Y are

If 1 mole of sodium contains 6 x 10²³ atoms, how many atoms are contained in 0.6 g of sodium? [Na = 23]

If 20 cm³ of distilled water is added to 80cm ³ of 0. 50 mol dm^-3 hydrochloric acid, the new concentration of the acid will be

Consider the reaction represented by the equation. 2NaHCO_3(s) \(\rightarrow\) 2Na₂CO _3(S) + CO _2(g) + H₂O_(g) what volume of carbon (IV)oxide at s.t.p is evolved when 0. 5 moles of NaHCO₃ is heated? [Molar volume = 22.4 dm³ at s.t. p]

Considered the reaction: H⁺_(aq) + OH ^-_(aq) → H₂O_(l). The energy change taking place in the reaction above is enthalpy of