Answer:
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%
The correct answer is 2.70 × 10² g or 270 g.
It is given, that the density of a metal is 9.80 g/ml.
Let the mass of a sample of metal be x.
The sample of metal is dropped in 28.9 ml of water, due to which the volume of the water increases to 56.4 ml.
In order to calculate the mass of a metal, there is a need to use the formula, mass = density * volume
Mass = (9.80 g/ml) (56.4 ml - 28.9 ml)
= (9.80 g/ml) (27.5 ml)
= 2.70 × 10² g or 270 g
Answer: the answer would be D
Explanation:In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy in the form of heat in the winter and reject solar heat in the summer. an example of this would be a green house in the winter the sun is still out but the windows keep out the cold air so the sun just heats up the air inside
Answer:
2.3 x 10-23 g.
Explanation:
The mass of a single atom is the mass number, 14, is the mass in grams of one mole of carbon.
One mole of Nitrogen atom is 6.022 x 1023 atoms (Avogadro's number). This can then used to convert a nitogen atom to grams by the ratio:
mass of 1 atom / 1 atom = mass of a mole of atoms / 6.022 x 10^23 atoms.
mass of 1 atom = mass of a mole of atoms / 6.022 x 1023
mass of 1 N atom = 14 / 6.022 x 10^23 N atoms
mass of 1 N atom = 2.325 x 10^-23 g
The mass of a single Nitrogen atom is 2.325 x 10-23 g.
The H+ will react with Magnesium to release hydrogen Gas under the equation Mg + 2H+ --> Mg(2+) + H2(g)
Hope this Helps! :)
