Zadania z chemii IB SL

The sealed vessel was left for the reaction to proceed. Suggest two properties of the system, other than its colour, that could be measured to follow the progress of the reaction over time, and predict how each would change as the forward reaction proceeds.

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. (i) Write an…

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 chemical reaction occurs in a mixture that starts at the same temperature as its surroundings. Immediately after the reaction, the mixture is warmer than before. Which row correctly describes the energy changes in the system and in the surroundings as 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. $\ce{2Mg(s) + O2(g) -> 2MgO(s)}$

The enthalpy change of a reaction is $\Delta H = +58\ \mathrm{kJ\,mol^{-1}}$. Which statement about this reaction is correct? A. The reaction is endothermic and the products are less stable than the reactants. B. The reaction is endothermic and the products…