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Which statement best explains why a block of copper can be hammered into a thin sheet without breaking? A. Cations in neighbouring layers repel one another, so they stay fixed in their positions B. Layers of cations can slide over one another because the…
Cyclopentane is a component of petrol. Its specific energy, the energy released per kilogram of fuel burned, is 4.69 × 107 J kg−1. Calculate the enthalpy of combustion of cyclopentane, C5H10, in kJ mol−1. Use…
A 52.0 g piece of zinc at 90.0 °C is dropped into 80.0 cm3 of water at 20.0 °C. The final temperature of the water is 24.0 °C. The specific heat capacity of zinc is…
Natural gas, which is mainly methane, and coal, which is mainly carbon, are both burned in power stations. Outline why burning natural gas has a lower environmental impact than burning coal.
What are the numbers of sigma and pi bonds in a molecule of propenenitrile, CH2=CH−C≡N? A. 6 sigma bonds and 3 pi bonds B. 7 sigma bonds and 3 pi bonds C. 6 sigma bonds and 2 pi bonds D. 9 sigma bonds and no pi bonds
Lidocaine and procaine are local anaesthetics. Their structures are shown. Deduce the name of one functional group that is present in both molecules and the name of one functional group that is present in procaine only.
Which expression can be used to calculate the standard enthalpy change of a reaction, ΔH⊖, from standard enthalpies of combustion? A.…
Which molecule is non-polar? A. SF4 B. ClF3 C. BrF5 D. XeF4
Which change represents the first electron affinity of chlorine? A. Cl2(g) → 2 Cl(g) B. Cl(g) + e− → Cl−(g) C. Cl(g) → Cl+(g) + e− D. Cl−(g) → Cl(g) + e−
A student determined the enthalpy change of combustion of ethanol by burning it in a spirit burner under a copper can containing 150 cm3 of water. The value obtained was less exothermic than the literature value. Which modification would improve the…