Zapisujemy na Twoim urządzeniu to, bez czego serwis nie działa, np. zalogowanie. Plików analitycznych użyjemy tylko za Twoją zgodą. Szczegóły w polityce prywatności.
Baza zadań
Wybierz umiejętność, rok lub poziom trudności. Każde zadanie ma klucz i schemat punktowania.
Pokazujemy tylko poziomy, dla których mamy zadania.
Znaleziono 1061 zadań
A rigid cylinder of fixed volume contains N molecules of an ideal gas at 200 K and a pressure of 80 kPa. Half of the molecules are removed and the temperature of the remaining gas is raised to 500 K. What is the new pressure of the gas, in kPa? A. 16 B. 40…
(i) Write an equation for the homolytic fission of a bromine molecule under UV light, using curly arrows to show the movement of electrons. (ii) Under different conditions a bromine molecule can undergo heterolytic fission. Write an equation for this process,…
The graph shows the boiling points of five straight-chain carboxylic acids and of the five methyl esters that have the same relative formula masses as the acids. (i) Outline why the carboxylic acids have higher boiling points than the esters with the same…
Nitric acid is a strong acid manufactured on a large scale. A pH probe is immersed in a small volume of 0.010 mol dm−3 nitric acid. The pH is recorded while distilled water is added to the acid at a steady rate and at constant temperature. (i)…
What is the formula of the compound formed between aluminium ions and sulfate ions? A. AlSO4 B. Al2(SO4)3 C. Al(SO4)3 D. Al3(SO4)2
Which species contains a coordination bond? A. NH3 B. H3O+ C. CH4 D. BF3
Which properties of copper depend on the movement of its delocalized electrons? I. electrical conductivity of the molten metal II. thermal conductivity III. high density A. I and II only B. I and III only C. II and III only D. I, II and III
The table shows the average electronegativity and the electronegativity difference for four substances, each made from two elements. Which substance is an alloy? A. P B. Q C. R D. S
Which structure shows the repeating unit of the addition polymer formed from pent-1-ene? A. [CH2−CH2−CH(CH2CH3)]n B. [CH(CH3)−CH(CH2CH3)]n C. [CH2−CH(CH2CH2CH3)]n D. [CH2−C(CH3)(CH2CH3)]n
What is the explanation for the ductility of copper, which allows it to be drawn into wires? A. The attraction between the cations and the delocalized electrons is weak. B. The cations are held in the lattice by strong bonds that act in fixed directions. C.…