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
Glucose, C6H12O6, is a monosaccharide that is oxidized in the body to carbon dioxide and water. The standard enthalpy change of combustion of glucose is −2803 kJ mol−1. Calculate the energy, in kJ, released by the complete combustion of…
An element has the electron configuration 1s2 2s2 2p6 3s2 3p4. How many electrons are gained or lost when an atom of this element forms an ionic bond? A. Four electrons lost B. Two electrons lost C. Four electrons gained D. Two electrons gained
Which compound is both volatile and soluble in water? A. C6H14 B. KBr C. SiO2 D. CH3CH2OH
Four solids, P, Q, R and S, were tested. The results are shown in the table. Which solid most likely has an ionic lattice structure? A. P B. Q C. R D. S
The nitrogen-nitrogen bonds in hydrazine, N2H4, diazene, N2H2, and nitrogen, N2, are N−N, N=N and N≡N. Which row gives these bonds in order of increasing bond strength and in order of increasing bond length? A. Bond…
Magnesium has a higher melting point than sodium. Which statement best explains this? A. Magnesium atoms have a greater relative atomic mass than sodium atoms B. Magnesium has a lower first ionization energy than sodium C. Magnesium ions have a larger radius…
Methanol, CH3OH, can be used as a fuel. The standard enthalpy of combustion of methanol is −726 kJ mol−1. Calculate the mass of carbon dioxide produced per 1000 kJ of heat released by the complete combustion of methanol.
The global warming potential (GWP) of a gas compares the heat it absorbs with the heat absorbed by an equal mass of carbon dioxide. The GWP of the refrigerant C2H2F4 is approximately 1300. Estimate the heat absorbed by one mole of C2H2F4 relative…
What is the electron domain geometry of phosphine, PH3? A. trigonal planar B. trigonal pyramidal C. tetrahedral D. bent
(i) Write the balanced equation for photosynthesis, in which glucose is formed. (ii) Explain how the large-scale planting of fast-growing trees is intended to reduce the rate of global warming.