Zadania z chemii IB HL

Suppose carbonyl dibromide were made by a free-radical chain reaction of carbon monoxide, $\ce{CO}$, with bromine vapour, $\ce{Br2}$, started by ultraviolet light. The questions below treat this hypothetical route with the bond-enthalpy model and the entropy…

The energy profile below was recorded for a reaction. Which pair of statements is consistent with it? In each option the first statement compares the enthalpy of the products with that of the reactants and the second gives the sign of $\Delta H$. A. products…

Which row correctly describes an endothermic reaction? A. The temperature of the surroundings rises and the products are more stable than the reactants. B. The temperature of the surroundings falls and the products are more stable than the reactants. C. The…

A student stirred 0.030 mol of solid sodium hydrogencarbonate into 40 $\mathrm{cm^3}$ of a 1.0 $\mathrm{mol\,dm^{-3}}$ solution of ethanedioic acid. $\ce{H2C2O4(aq) + 2NaHCO3(s) -> Na2C2O4(aq) + 2CO2(g) + 2H2O(l)}$ The temperature of the solution fell from…

The forward reaction is endothermic, uses platinum as a catalyst, and takes place at 800 K. Sketch the reaction's energy profile both with and without the catalyst present, labelling the activation energies and $\Delta H$.

The potential energy profile of a reaction is shown. Which reaction has this energy profile? A. $\ce{Cl2(g) -> 2Cl(g)}$ B. $\ce{CaCO3(s) -> CaO(s) + CO2(g)}$ C. $\ce{N2O4(g) -> 2NO2(g)}$ D. $\ce{2Mg(s) + O2(g) -> 2MgO(s)}$

A student mixes a solution of citric acid with solid sodium hydrogencarbonate in an insulated polystyrene cup fitted with a thermometer. The energy profile of the reaction is shown. Which combination is correct? A. the temperature of the solution rises;…