A tank contains one hundred fifty kmol of an aqueous phosphoric acid solution with 5.00 mole% H3PO4. The solution is concentrated by adding pure phosphoric acid at a rate of 30.0 L/min. Molecular weight of phosphoric acid is 98. Density of phosphoric acid is 1.834 kg/L. Determine the mole fraction of phosphoric acid in the tank at 25 minutes.

Mole fraction  = 0.1313

Explanation:

given data

Addition rate of pure phosphoric acid = 30L/min

Phosphoric acid added in 25 min = 750 L

solution

mass is express as here

mass = density × volume and number of moles = mass ÷ molar mass

So, In terms of moles

phosphoric acid added = (750 × 1.834) ÷ 98

phosphoric acid added = 14.036 kmol

and

moles of phosphoric acid in tank = 0.05 × 150 + 14.036

moles of phosphoric acid in tank = 21.536 kmol

and

Moles of water in tank = 0.95 × 150

Moles of water in tank = 142.5 kmol

So that Mole fraction of phosphoric acid in tank

Mole fraction = 21.536 ÷ (21.536+142.5)

Mole fraction  = 0.1313

answer: option (4) is the correct answer.

explanation:

areas which are at low altitudes and near the equator tend to receive direct sunlight from the sun. hence, heat energy or radiations from the sun make these areas warmer and they have warmest water.

whereas areas which are at high altitudes and away from the equator do no receive direct sunlight. hence, no direct contact from the sun makes these regions colder and thus, they have colder water.

thus, we can conclude that the statement areas at low latitudes near the equator have the warmest water because they receive the most direct sunlight best explains the relationship between an area's geography and the temperature of its surface water.