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Questions and Answers
What is the term used for a solid that dissolves in a liquid?
What is the term used for a solid that dissolves in a liquid?
Which process can be used to obtain a soluble solid from its solution?
Which process can be used to obtain a soluble solid from its solution?
When preparing a salt solution, what is collected as residue?
When preparing a salt solution, what is collected as residue?
What do you dissolve in a liquid to create a solution?
What do you dissolve in a liquid to create a solution?
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What is the liquid component of a solution called?
What is the liquid component of a solution called?
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What is the first liquid to distill when separating ethanol and water?
What is the first liquid to distill when separating ethanol and water?
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What is the purpose of the fractionating column in fractional distillation?
What is the purpose of the fractionating column in fractional distillation?
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Why should cold water enter the condenser at the bottom?
Why should cold water enter the condenser at the bottom?
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When should an ice bath be utilized during distillation?
When should an ice bath be utilized during distillation?
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Which characteristic defines miscible liquids?
Which characteristic defines miscible liquids?
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What happens to the less volatile substance during fractional distillation?
What happens to the less volatile substance during fractional distillation?
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What is the boiling point of ethanol?
What is the boiling point of ethanol?
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What type of mixtures is fractional distillation most commonly used to separate?
What type of mixtures is fractional distillation most commonly used to separate?
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What is a primary industrial application of fractional distillation?
What is a primary industrial application of fractional distillation?
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Which of the following describes a key difference between simple and fractional distillation?
Which of the following describes a key difference between simple and fractional distillation?
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In fractional distillation, what characteristic of the liquids in the mixture is essential?
In fractional distillation, what characteristic of the liquids in the mixture is essential?
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What is one of the products obtained from the fractional distillation of petroleum?
What is one of the products obtained from the fractional distillation of petroleum?
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Which statement accurately describes simple distillation?
Which statement accurately describes simple distillation?
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Why is fractional distillation preferred for separating ethanol from fermented liquor?
Why is fractional distillation preferred for separating ethanol from fermented liquor?
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Which process is NOT typically associated with fractional distillation?
Which process is NOT typically associated with fractional distillation?
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What must be true for two liquids to be suitable for fractional distillation?
What must be true for two liquids to be suitable for fractional distillation?
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What is the purpose of the start line in chromatography?
What is the purpose of the start line in chromatography?
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What characteristic does a pure dye exhibit on a chromatogram?
What characteristic does a pure dye exhibit on a chromatogram?
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Which type of dye remains at the start line during chromatography?
Which type of dye remains at the start line during chromatography?
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Which of the following statements is true regarding the movement of same dyes in chromatography?
Which of the following statements is true regarding the movement of same dyes in chromatography?
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What inference can be made about Dye G based on its description?
What inference can be made about Dye G based on its description?
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How does a mixture of dyes behave in a chromatography experiment?
How does a mixture of dyes behave in a chromatography experiment?
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What method may be used to test the purity of a substance besides chromatography?
What method may be used to test the purity of a substance besides chromatography?
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Which substance would likely be marked on the start line of a chromatography setup?
Which substance would likely be marked on the start line of a chromatography setup?
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What is indicated when a substance shows multiple spots on a chromatogram?
What is indicated when a substance shows multiple spots on a chromatogram?
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Why is it important for the start line to be marked with a substance that is insoluble in the solvent?
Why is it important for the start line to be marked with a substance that is insoluble in the solvent?
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What is the primary purpose of simple distillation?
What is the primary purpose of simple distillation?
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Which component of a distillation setup is essential for measuring the temperature of vapour?
Which component of a distillation setup is essential for measuring the temperature of vapour?
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What role do boiling chips play in the distillation process?
What role do boiling chips play in the distillation process?
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In the process of simple distillation, what happens to the solvent?
In the process of simple distillation, what happens to the solvent?
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Which example best illustrates the use of simple distillation?
Which example best illustrates the use of simple distillation?
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What is the purpose of the condenser in a distillation setup?
What is the purpose of the condenser in a distillation setup?
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What precaution should be taken when placing the thermometer in a distillation setup?
What precaution should be taken when placing the thermometer in a distillation setup?
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Which of the following steps is not performed when drying crystals?
Which of the following steps is not performed when drying crystals?
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Which apparatus is used to measure mass most accurately?
Which apparatus is used to measure mass most accurately?
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What is the SI unit for measuring temperature?
What is the SI unit for measuring temperature?
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Which method is suitable for collecting gases that are less dense than air?
Which method is suitable for collecting gases that are less dense than air?
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Which of the following apparatus measures fixed volumes of liquids?
Which of the following apparatus measures fixed volumes of liquids?
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To collect a gas that is soluble in water, which method should be used?
To collect a gas that is soluble in water, which method should be used?
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What is the degree of accuracy for measuring time with a stopwatch?
What is the degree of accuracy for measuring time with a stopwatch?
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Which gas is an example of one that can be collected using downward delivery?
Which gas is an example of one that can be collected using downward delivery?
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What is the unit used to measure the volume of gas in cm^3?
What is the unit used to measure the volume of gas in cm^3?
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Which apparatus is typically used for measuring large volumes of liquid correctly?
Which apparatus is typically used for measuring large volumes of liquid correctly?
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What is the degree of accuracy for measuring volume with a burette?
What is the degree of accuracy for measuring volume with a burette?
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Study Notes
Physical Quantities and Measurement
- Mass: Measured using an electronic balance. SI unit is kg. Accuracy is typically to the nearest 0.01 g.
- Temperature: Measured using a thermometer. SI unit is K (Kelvin). Accuracy is typically to the nearest 0.5 °C.
- Time: Measured using a stopwatch. SI unit is s (seconds). Accuracy is typically to the nearest 0.01 s.
- Volume of Gas: Measured using a gas syringe, the volume measured varies with the syringe provided, typically from 0 cm³ to 100 cm³. Accuracy is typically to the nearest 0.5 cm³.
- Volume of Liquid: Measured using a pipette (fixed volumes) or a burette. The pipette measures fixed volumes, such that 25.0 cm³ measurements are possible. Burettes measure volumes to the nearest 0.05 cm³.
Collecting Gases
- Methods: Gases can be collected using water displacement, upward/downward delivery, or a gas syringe.
- Insoluble in Water: Gases like carbon dioxide, hydrogen, and oxygen are collected by water displacement.
- Soluble in Water, Less Dense than Air: Ammonia is collected by upward delivery.
- Soluble in Water, More Dense than Air: Chlorine and hydrogen chloride are collected by downward delivery.
- Any gas: A gas syringe can be used to collect any gas by measuring its volume.
Separation Techniques
- Filtration: Used to separate an insoluble solid from a liquid. Examples are separating sand and water or chalk and water.
- Dissolution: Used to separate a soluble solid from an insoluble solid. Distinguish between the soluble solid (e.g., salt) and the insoluble solid (e.g., sand), using water. The process dissolves the salt, the insoluble solid (sand) is filtered out.
- Evaporation/Crystallization: Evaporating the solvent leaves the dissolved solid as crystals, purifying it. Salts can be obtained from sea water by evaporating the water.
- Crystallisation: For obtaining a solid of known purity, instead of evaporation, one can crystallize the solute once evaporation is complete from the filtrate instead.
Evaporation to Dryness
- Sometimes a substance decomposes on heating, such as sugar. In these cases, crystallisation is used instead of evaporation. The purpose of evaporation is to evaporate the solvent.
- To separate a solute-solvent mixture (e.g., soluble solid-liquid mixture):
- Place the solution in an evaporating dish
- Evaporate the solvent until it is removed and the pure solid remains.
Crystallization
- Used when one needs a purified substance with specific crystalline form.
- This technique is used when evaporation is not possible due to the decomposition of the solute.
Simple Distillation
- To separate mixtures of soluble solids and liquid mixtures.
- Heat a solution until the liquid turns into a vapour.
- Then cool the vapour to turn it back to a liquid (condense).
- Collect the pure liquid.
Fractional Distillation
- To separate two or more liquids with different boiling points.
- This method uses a fractionating column, which provides surface area allowing repeated boiling and condensation to occur.
- The less volatile/high boiling point substance is retained in the flask, while the more volatile substance vaporizes and moves up the column.
- Collect the vaporized liquid as it condenses back into liquid in the cooler portion of the column.
Industrial Applications of Fractional Distillation
- Used in obtaining different substances from crude oil.
- Used in separating the components of liquid air.
- Used in separating ethanol from fermented liquors.
Other Separation Methods
- Using a Magnet: Use a magnet to separate magnetic materials (e.g., iron, nickel, cobalt, steel) from non-magnetic materials (e.g., sulphur)
- Chromatography: A technique used to separate substances based on different solubilities in a solvent. -The substance which is more soluble in the solvent moves more quickly.
- Melting and Boiling Points: Pure substances have well defined melting and boiling points. Impure substances have a range of temperatures for melting or boiling. Melting or boiling points can change depending on the presence of impurities: most substances' melting points decrease and their boiling points increase if impurities are present
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Description
This quiz covers the essential concepts of physical quantities and their measurements, including mass, temperature, time, and volume of gases and liquids. You'll also explore methods of collecting gases through different techniques. Test your understanding of the accuracy and units associated with these measurements.
