4.000 g of compound x with molecular formula c4h6 are burned in a constant-pressure calorimeter containing 40.00 kg of water at 25 °c. the temperature of the water is observed to rise by 1.065 °c. (you may assume all the heat released by the reaction is absorbed by the water, and none by the calorimeter itself.) calculate the standard heat of formation of compound x at 25 °c. be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.

2407 kJ/mol

Explanation:

Given:

Mass of water  = 40.00 kg

 = 1.065 °C

Net Heat transfer during heating:

Specific heat of water = 4.187 kJ/kg°C  

Q = 178.3662 kJ

Heat gained by water is heat lost by the compound. Thus, heat lost = 178.3662 kJ

Also,

Mass = 4.000 g

Molar mass of

The formula for the calculation of moles is shown below:

Thus,

Standard heat of formation = 178.3662 kJ / 0.0741 mol=2407 kJ/mol (In correct significant digits)

35. a insulated cylinder of solid gold (k 310 kw/m-k) of radius v2 m and height 5 m is heated at one end until the temperature at each point in the cylinder is given by w(r, y, z) (30 z2)(2-(r2+ y2). determine the rate of heat flow across each horizontal disk given by z 1, z 2, and z 3, identifying which has the greatest rate of heat flow across it.

explanation: