1.
Fractional distillation separates two liquids for which the difference in boiling point is at least what?
Correct Answer
A. 25K
Explanation
Fractional distillation is a process used to separate two liquids based on their boiling points. The liquids are heated, and the one with the lower boiling point vaporizes first, while the one with the higher boiling point remains in liquid form. The difference in boiling points between the two liquids should be greater than a certain value for effective separation. In this case, the correct answer is 25K, indicating that the boiling points of the two liquids being separated should have a difference of at least 25 Kelvin for successful fractional distillation.
2.
Fractional Distillation is an effective way to separate two miscible liquids that differ in what?
Correct Answer
C. Boiling point
Explanation
Fractional distillation is an effective way to separate two miscible liquids that differ in boiling point. This process takes advantage of the fact that liquids have different boiling points and can be vaporized and condensed separately. The mixture is heated, and the component with the lower boiling point vaporizes first and is collected. The remaining liquid is then heated further to vaporize the component with the higher boiling point. By collecting the vapors at different temperatures, the two liquids can be separated based on their boiling points.
3.
What is the first physical process to happen in distillation?
Correct Answer
C. Evaporation
Explanation
Evaporation is the first physical process to occur in distillation. During distillation, a liquid mixture is heated, causing the more volatile components to evaporate. These vapors are then collected and condensed back into a liquid form through cooling. The process of evaporation separates the different components of the mixture based on their boiling points, allowing for the purification and separation of substances.
4.
The process used to purify or concentrate liquids is commonly known as what?
Correct Answer
A. Distillation
Explanation
Distillation is the correct answer because it is a widely used process for purifying or concentrating liquids. It involves heating the liquid to create vapor, and then cooling and condensing the vapor back into liquid form. This process separates the different components of the liquid based on their boiling points, allowing for the removal of impurities or the concentration of desired substances. Fermentation is a different process used to convert sugars into alcohol, and cryogenic distillation refers to distillation carried out at extremely low temperatures. Therefore, neither of these options is the correct answer.
5.
The compound that contains only hydrogen and carbon is known as what?
Correct Answer
D. Hydrocarbon
Explanation
A compound that contains only hydrogen and carbon is known as a hydrocarbon. This is because hydrocarbons are organic compounds composed exclusively of hydrogen and carbon atoms. They are the simplest and most abundant class of organic compounds and are the basis for many important substances, such as fossil fuels and organic molecules found in living organisms.
6.
Which of the following substances can be easily separated by fractional distillation?
Correct Answer
B. Oil bath
Explanation
Oil bath can be easily separated by fractional distillation. Fractional distillation is a process used to separate different components of a mixture based on their different boiling points. Oil has a higher boiling point compared to other substances like glycerine and water, which allows it to be easily separated by fractional distillation.
7.
What does the viscosity of the hydrocarbon tell us?
Correct Answer
C. Viscosity means the easy of flow of the hydrocarbon
Explanation
The correct answer is "Viscosity means the ease of flow of the hydrocarbon." Viscosity is a measure of a fluid's resistance to flow. A high viscosity indicates a thicker fluid that flows more slowly, while a low viscosity indicates a thinner fluid that flows more easily. In the context of hydrocarbons, viscosity is used to describe how easily the hydrocarbon can flow or move.
8.
What happens to a crude oil fraction when its temperature falls below its boiling point?
Correct Answer
C. It condensates
Explanation
When a crude oil fraction's temperature falls below its boiling point, it undergoes a process called condensation. Condensation occurs when a substance changes from a gas to a liquid state due to a decrease in temperature. In this case, the crude oil fraction loses heat and transitions from a vapor to a liquid form.
9.
A hydrocarbon C4H10 has a boiling point of 0°C. Another hydrocarbon C6H14 has a boiling point of 69°C. What would you expect the boiling point of C8H18 to be?
Correct Answer
C. 125 Degree C
Explanation
The boiling point of a hydrocarbon generally increases with an increase in the size of its molecule. Since C8H18 has a larger molecule compared to C6H14, it is expected to have a higher boiling point. Therefore, the boiling point of C8H18 would be expected to be higher than 69°C. Among the given options, the closest value to this expectation is 125°C.
10.
The difference between fractional distillation and distillation is due to the presence of what?
Correct Answer
C. Fractionating column
Explanation
The difference between fractional distillation and simple distillation is primarily due to the presence of a fractionating column in fractional distillation. Fractional distillation includes a fractionating column filled with structured packing material. As the vapor rises through the column, it condenses and re-evaporates multiple times. This allows for more effective separation of components with similar boiling points, as it provides additional surface area and opportunities for condensation and vaporization within the column.