Zapisujemy na Twoim urządzeniu to, bez czego serwis nie działa, np. zalogowanie. Plików analitycznych użyjemy tylko za Twoją zgodą. Szczegóły w polityce prywatności.
Wybierz umiejętność, rok lub poziom trudności.
Pokazujemy tylko poziomy, dla których mamy zadania.
Znaleziono 1476 zadań
The ionic product constant of pure water, Kw, is 1.00 × 10−14 at 25 °C and 5.48 × 10−14 at 50 °C. (i) Suggest why the value of Kw for pure water becomes larger as the temperature rises. (ii) Calculate both the pH and the pOH of pure…
(i) Predict the number of signals in the 1H NMR spectrum of 3-methylbutanoic acid and the ratio of their areas. (ii) Predict the splitting pattern of the signal due to the two hydrogen atoms of the CH2 group. (iii) State one reason why…
The mass spectrum of 3-methylbutanoic acid is shown. (i) Suggest why the spectrum shows a small peak at m/z 103. (ii) Identify the fragments responsible for the peaks at m/z 87 and m/z 57. Use section 22 of the data booklet.
Predict one wavenumber at which an absorption, other than that of a C–H bond, appears in the infrared spectrum of 3-methylbutanoic acid. Use section 20 of the data booklet.
3-Methylbutanoic acid reacts with propan-1-ol, CH3CH2CH2OH, to form an organic product and water. Deduce the structural formula and the empirical formula of the organic product.
Which statement correctly compares infrared and ultraviolet radiation? A. Infrared radiation has a longer wavelength and a lower photon energy than ultraviolet radiation. B. Infrared radiation has a longer wavelength and a higher frequency than ultraviolet…
Nitrogen dioxide, NO2, is one of the brown pollutant gases in photochemical smog. It can react with carbon monoxide, which is also present in polluted air. NO2(g) + CO(g) → NO(g) + CO2(g) (i) Suggest how the rate of this reaction could be…
The nitrite ion, NO2−, can form complexes with transition element ions such as Co3+ and Ni2+. Describe the type of bonding between the nitrite ion and the metal ion in such a complex, and state the role of the nitrite ion in acid-base…
Iron(III) ions catalyse the decomposition of hydrogen peroxide but zinc ions do not. Outline why.
The graph shows the first ten successive ionization energies of an element. Which element is it? A. N B. Si C. P D. Cl