1990 National Test Go to the answers 1. The freezing point constant is water, k f , is 1.86 K m 1 . Enthapies of formation cannot be measured for many compounds directly, and must be calculated from combustion data. Given the following data, calculate the heat of formation of glucose, C 6 H 12 O 6 . H 3 CCH 3 11.
Ionic compounds are hard, brittle solids with high melting points.
Some compounds which exhibit primarily ionic bonding in the solid phase can form covalent bonds in the gas phase. The lattice energy is the quantity of energy required for 1 mol of a solid ionic substance to be separated completely into gaseous ions well removed from one another. In general the lattice energy increases as the charge on the anion and cation increase and increases as the size of the anion and cation decrease. The pH of a saturated solution of calcium hydroxide is 12.40. The mass of a nitrogen gas molecule is 14 times that of a hydrogen molecule.