Chemistry, 19.12.2019 01:31, gracerhodes4305

Ethanol (ch3ch2oh) has been suggested as an alternative fuel source. ethanol’s enthalpy of combustion is hcomb = –1368 kj/mol.

what volume of ethanol (d = 0.789 g/ml) is required to produce the same amount of energy as 1 gallon of gasoline, which can be modeled as isooctane (c8h18, d = 0.703 g/ml) with an energy density of 32.9 kj/ml? (1 gal = 3.785 l)

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answered: datboyjulio21

5.3072 Liters of volume of ethanol is required.

Explanation:

Volume of isooctane = 1 gal = 3.785 L

3.785 L =3.785 × 1000 mL= 3,785 mL

Energy density of isooctane = 32.9 kJ/mL

Energy produced on combustion of 3,785 mL of isooctane :

$E=32.9 kJ/mL\times 3,785 mL=124,526.5 kJ$

Moles of ethanol which will produce same amount of energy 'E' as 1 gallon of iosooctane = n

Ethanol’s enthalpy of combustion = $\Delta H_{comb}=-1,368 kJ/mol$

Energy released when 1 mole of ethanol is combusted = 1,368 kJ/mol

$E=n\times 1,368 kJ/mol$

$n=\frac{E}{1,368 kJ/mol}=\frac{124,526.5 kJ}{1,368 kJ/mol}$

n = 91.03 mole

Mass of 91.03 moles of ethanol , m= 91.03 mol × 46 g/mol = 4,187.38 g

Volume of ethanol = V

Density of ethanol = d = 0.789 g/mL

$Volume=\frac{Mass}{density}$

$V=\frac{m}{d}=\frac{4,187.38 g}{0.789 g/mL}=5,307.2 mL= 5.3072 L$

5.3072 Liters of volume of ethanol is required.

answered: Guest

water molecules stay close to each other through cohesion, the collective action of hydrogen bonds between water molecules. cohesion plants draw water upwards from the root through the stem's transport tubes (xylem) to the leaf. this transport occurs even in large trees and against gravity. transpiration, evaporation of water from plant leaves, creates a tension on water molecules being pulled up from the stem and roots.

water also has high (the attraction of one substance to another) properties because of its polar nature. adhesion of water molecules to plant cell walls counteract gravity while water is transported from roots to leaves.

water exhibits a very high surface tension when compared to other liquids. surface tension is a property of a liquid that holds the surface together and allows it to resist an external force. by capillary action, the water forms concave menisci inside the pores. the high surface tension of water pulls the concavity outwards, generating enough force to lift water from the roots to the leaves of plants.

thus, cohesion, along with adhesion and surface tension creates a capillary action that keeps water molecules interacting and moving through the plants out to the leaf cells.

therefore, option d) is the correct answer.

explanation:

answered: Guest

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