In this reaction, the chromium is reduced, from cr6+ to cr3+, causing a color change in the solution, signaling the endpoint. determine the mass percent ethanol in a 40.0 g blood sample, if the sample required 22.6 ml of 0.05 m k2cr2o7 to react completely with all the ethanol answers

Using the information provided in the question, the percentage by mass of ethanol in the blood is 0.1949%.

Explanation:

The balanced equation for the reaction can be written as:

3CH3CH2OH + 2K2Cr2O7+ 16H+ >>>> 3CH3COOH + 4Cr3+ + 4K+ + 11H2O. This will be used to solve the problem.

The no of moles of K2Cr2O7 used = concentration X volume in dm cube.

= 0.05 X 22.6/1000 = 1.13/1000 = 0.00113 moles of K2Cr2O7 was used.

From the balanced equation above, 3 moles of ethanol will react with 2 moles of K2Cr2O7.

Therefore, 0.00113 X 3/2 moles of ethanol would have been in the blood of the subject = 0.001695 moles of ethanol.

Remember that no of moles = mass/molar mass. Then mass = moles X molar mass.

The molar mass of ethanol is 46g/mole.

Then mass = 0.001695 X 46 = 0.07797gram of Ethanol was in the blood.

Percentage by mass in blood is: 0.07797/40 X 100 = 0.1949%

a boiling water reactor does not boil the water. a pressurized water reactor boils the water faster. a pressurized water reactor is heated directly by the core. a pressurized water reactor does not use fission.

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.