Regents Chemistry Test Preparation Practice Separation Of The Components Of A Mixture

A mixture of sand and table salt can be separated by filtration because the substances in the mixture differ in*

(1) boiling point

(2) density at STP

(3) freezing point

(4) solubility in water

Given the diagram representing a process being used to separate the colored dyes in food coloring:

physical-behavior-of-matter, separation-of-the-components-of-a-mixture fig: chem12013-exam_g13.png

Which process is represented by this diagram?*

(1) chromatography

(2) electrolysis

(3) distillation

(4) titration

Equal amounts of ethanol and water are mixed at room temperature and at 101.3 kPa. Which process is used to separate ethanol from the mixture?*

(1) distillation

(2) reduction

(3) filtration

(4) ionization

Two substances in a mixture differ in density and particle size. These properties can be used to*

(1) separate the substances

(2) chemically combine the substances

(3) determine the freezing point of the mixture

(4) predict the electrical conductivity of the mixture

Differences in which property allow the separation of a sample of sand and seawater by filtration?*

(1) concentration of ions

(2) volume of sample

(3) mass of sample

(4) particle size

Given the formulas representing two compounds at standard pressure:

physical-behavior-of-matter, separation-of-the-components-of-a-mixture fig: chem12017-exam_g10.png

The compounds can be differentiated by their*

(1) boiling points

(2) gram-formula masses

(3) numbers of hydrogen atoms

(4) percent compositions by mass of carbon

A mixture consists of ethanol and water. Some properties of ethanol and water are given in the table below.

physical-behavior-of-matter, separation-of-the-components-of-a-mixture fig: chem12019-exam_g7.png

Which statement describes a property of ethanol after being separated from the mixture?*

(1) Ethanol is nonflammable.

(2) Ethanol has a melting point of 0.°C.

(3) Ethanol has a density of 0.80 g/cm³ at STP.

(4) Ethanol has a boiling point of 89°C at standard pressure.

A 1-gram sample of a compound is added to 100 grams of H₂O(ℓ) and the resulting mixture is then thoroughly stirred. Some of the compound is then separated from the mixture by filtration. Based on Table F, the compound could be*

(1) AgCl

(2) CaCl₂

(3) NaCl

(4) NiCl₂

Which process is commonly used to separate a mixture of ethanol and water?*

(1) distillation

(2) ionization

(3) filtration

(4) titration

At STP, two 5.0-gram solid samples of different ionic compounds have the same density. These solid samples could be differentiated by their*

(1) mass

(2) volume

(3) temperature

(4) solubility in water

Base your answers to questions 11 on the information below and on your knowledge of chemistry.

A student prepares two 141-gram mixtures, A and B. Each mixture consists of NH₄Cl, sand, and H₂O at 15°C. Both mixtures are thoroughly stirred and allowed to stand. The mass of each component used to make the mixtures is listed in the data table below.

physical-behavior-of-matter, classification-of-matter, physical-behavior-of-matter, features-of-mixture fig: chem12016-exam_g10.png

Describe one property of sand that would enable the student to separate the sand from the other components in mixture B.*

Base your answers to questions 12 on the information below and on your knowledge of chemistry.

In a laboratory investigation, a student is given a sample that is a mixture of 3.0 grams of NaCl(s) and 4.0 grams of sand, which is mostly SiO₂(s). The purpose of the investigation is to separate and recover the compounds in the sample. In the first step, the student places the sample in a 250-mL flask. Then, 50. grams of distilled water are added to the flask, and the contents are thoroughly stirred. The mixture in the flask is then filtered, using the equipment represented by the diagram below.

physical-behavior-of-matter, solutions, physical-behavior-of-matter, separation-of-the-components-of-a-mixture fig: chem12019-exam_g15.png

Explain, in terms of solubility, why the mixture in the flask remains heterogeneous even after thorough stirring.*

Base your answers to questions 13 on the information below and on your knowledge of chemistry.

Crude oil, primarily a mixture of hydrocarbons, is separated into useful components in a fractionating tower. At the bottom of the tower, the crude oil is heated to about 400°C. The gases formed rise and cool. Most of the gases condense and are collected as liquid fractions. The table below shows the temperature ranges for collecting various hydrocarbon fractions.

organic-chemistry, hydrocarbons fig: chem12019-exam_g17.png

State the temperature range for the fraction collected that contains octane molecules.*

Base your answers to questions 14 on the information below and on your knowledge of chemistry.

In the late 19th century, the Hall-Herroult process was invented as an inexpensive way to produce aluminum. In this process, Al₂O₃(ℓ) extracted from bauxite is dissolved in Na₃AlF₆(ℓ) in a graphite-lined tank, as shown in the diagram below. The products are carbon dioxide and molten aluminum metal.

physical-behavior-of-matter, classification-of-matter fig: chem62013-exam_g18.png

Compare the density of the Al(ℓ) with the density of the mixture of Al₂O₃(ℓ) and Na₃AlF₆(ℓ).*

Base your answers to questions 15 on the information below and on your knowledge of chemistry.

Rubbing alcohol sold in stores is aqueous 2-propanol, CH₃CHOHCH₃(aq). Rubbing alcohol is available in concentrations of 70.% and 91% 2-propanol by volume.

To make 100. mL of 70.% aqueous 2-propanol, 70. mL of 2-propanol is diluted with enough water to produce a total volume of 100. mL. In a laboratory investigation, a student is given a 132-mL sample of 91% aqueous 2-propanol to separate using the process of distillation.

Identify the property of the components that makes it possible to use distillation to separate the 2-propanol from water.*