Zadania z chemii IB SL

Znalezionych zadań: 362

Filtry i umiejętności

What is correct about the species $\ce{^{65}Zn^{2+}}$

? A. 65 protons, 65 neutrons, 63 electrons B. 30 protons, 35 neutrons, 28 electrons C. 30 protons, 65 neutrons, 28 electrons D. 65 protons, 35 neutrons, 63 electrons

(a) The graph shows how the water level of the Salton Sea has changed since 1950. The reference point for the water level is sea level. (i) Suggest a reason why the values plotted on the vertical axis are negative. (ii) The surface area of the Salton Sea was…

(b) A variety of ions are dissolved in the water of the Salton Sea. The concentrations of the major ions are shown in the table below, based on two different sources (both scientific journals). Ion Concentration / $\mathrm{g\,dm^{-3}}$ , based on Source 1…

(c) A simple set-up was used to compare the conductivity of water samples obtained from the Salton Sea at different depths. The following data were obtained: Depth water sample was obtained from / m ( $\pm 0.05\ \mathrm{m}$ ) Electric current recorded by the…

(i) The first step is the catalytic oxidation of ammonia gas to nitrogen monoxide. $\ce{4NH3(g) + 5O2(g) -> 4NO(g) + 6H2O(g)}$ Determine the volume, in dm $^3$ , of nitrogen monoxide produced from 20.0 g of ammonia, at STP, using section 2 of the data booklet.…

The second step converts nitrogen monoxide to nitrogen dioxide. $\ce{2NO(g) + O2(g) <=> 2NO2(g)}$ $\Delta H^\ominus = -114\ \mathrm{kJ\,mol^{-1}}$ (i) Identify the oxidation state of nitrogen in $\ce{NO}$ and in $\ce{NO2}$ . (ii) State the equilibrium constant…

The final step can be summarized as: $\ce{3NO2(g) + H2O(l) -> 2HNO3(aq) + NO(g)}$ $\Delta H^\ominus = -138\ \mathrm{kJ\,mol^{-1}}$ Describe the types of bonding found in the concentrated aqueous nitric acid product.

Nitric acid, $\ce{HNO3}$ , is strong, while nitrous acid, $\ce{HNO2}$ , is weak. (i) Outline the difference between a strong and a weak acid. (ii) Deduce the Lewis formula and the molecular geometry for the nitrite ion, $\ce{NO2-}$ .

Many rechargeable batteries use an alkaline electrolyte. In the nickel-cadmium cell, cadmium, $\ce{Cd}$ , is the anode. $\ce{Cd(OH)2(s) + 2e- -> Cd(s) + 2OH-(aq)}$ $\ce{NiO(OH)(s) + H2O(l) + e- -> Ni(OH)2(s) + OH-(aq)}$ Deduce the overall reaction for the cell.

Energy can also be produced by a hydrogen-oxygen fuel cell with an acidic electrolyte. (i) Deduce the half-equations for the electrode reactions in this fuel cell. (ii) Hydrogen produces a line emission spectrum with several lines in the visible region.…