1) Draw representations of both ionic solids in each set that show the relative differences in the sizes of the four ions, the ratio of cations to anions, and the charge on

each ion; identify which ionic solid will have the higher melting temperature; and justify

your answer. (Formula units that contain two ions must be drawn as networks consisting

of twelve ions in total. Formula units that contain more than two ions can be represented

as a single formula unit.)

NaCl or KBT

NaCl or MgS

BeF2 or LiF

CaO or CaCl2

MgO or Al2O3

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

gas

explanation:

smoke is the matter of a gas

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.