What amount of heat (in kJ) is required to convert 28.4 g of an unknown solid (MM = 67.44 g/mol) at -15.4 °C to a liquid at 42.7 °C? (specific heat capacity of solid = 1.95 J/g･°C; specific heat capacity of liquid = 1.18 J/g･°C; ∆Hfus = 5.72 kJ/mol; normal freezing point, Tempf = 28.3°C)

the answer is either b or c

answer: a tank of height h is filled with water and sits on the ground. water squirts from a hole at a height y above the ground and has a range r. for two y values, 0 and h, r is zero. determine the value of y for which the range will be a maximum.

explanation:

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

the answer for sodium is 0.186

the answer for rubidium is 0.251