Chemistry 360 Dr. Jean M. Standard Problem Set 6 Solutions 1. Three moles of an ideal gas expand isothermally and reversibly from 90 to 300 L at 300 K. (a) Calculate â¬ Î´ U m, â¬ mÎ S m, w per mole, and q per mole. For an ideal gas, â¬ Î´ U = C v T, or in terms of molar quantities, â¬Î´ U m = C v, m Î´ T.inally, since â¬ dS = dq rev T, for an isothermal process, the molar entropy change is â¬ Î´ S m = q m T = 3003J/mol300KÎ S m = 10.01Jmol â1 K â1. (b) If the expansion is carried out irreversibly by allowing the gas to expand rapidly into a vacuum, determine â¬ Î´ U m, â¬ S m, w per mole, and q per mole.
Almost every modern piano has 52 white keys and 36 black keys for a total of 88 keys (seven octaves plus a minor third, from A0 to C8). Many older pianos only have 85 keys (seven octaves from A0 to A7). Some piano manufacturers have extended the range further in one or both directions.
The modern standard piano has 88 keys. Different from your average piano... There is also type of piano called a Cottage piano which is missing the top and bottom octave of a normal sized 88 key keyboard and hence has 64 keys. There are many other styles of piano with varying numbers of keys. There are two BÃ¶sendorfer pianos that have more than 88 keys: the 7'4 BÃ¶sendorfer 225 has 92 keys, and the 9'6 BÃ¶sendorfer 290 has 97 keys.