Classification of Matter

A student is given a sample of matter and asked to determine whether it is an element, compound, or mixture. The student discovers that she cannot separate the components of the sample by physical means. However, she is able to separate the sample by chemical means into three different pure substances. The sample must be ________.

• an element

• a mixture

• a compound

• a solution

Coal consists of nearly pure carbon, an element. When coal burns in air, it combines with the element oxygen from the air. Which of the following best describes the product of burning coal?

• water, a heterogeneous mixture of atoms of hydrogen and oxygen

• carbon dioxide, a heterogeneous mixture of atoms of carbon and oxygen

• carbon dioxide, a homogeneous mixture of atoms of carbon gas and oxygen gas

• carbon dioxide, a compound of atoms of carbon and oxygen

Tags

NGSS.MS-PS1-5

A scientific artist is assigned the task of drawing an illustration depicting particles of a solid. Which of the following best describes the drawing the illustrator should make?

• spheres moving randomly and far apart

• spheres closely packed in a regular geometric pattern and vibrating in place

• spheres moving randomly and vibrating in place

• spheres sliding past one another and fairly close together

Tags

NGSS.MS-PS3-2

A chemist has been given a mixture of two liquids that form a solution. The liquids have different boiling points, densities, and colors. Which method should be used to most easily separate the two liquids?

• distillation

• filtration

• sedimentation

• evaporation

A student is given an unknown mixture and asked to determine whether it is a solution, suspension, or emulsion. How would the student eliminate a suspension?

• distill the mixture

• filter the mixture

• shake the mixture

• apply an electric current through the mixture

Gold is yellow, shiny, smooth, and is found in the ground. A geologist finds a material that she thinks may be gold. Which of the following tests would reveal that the material is not gold and not an element?

• Its density is different from that of gold

• Its melting point is different from that of gold.

• The material is composed of two different substances.

• Its boiling point differs from that of gold.

A chemist is given a container filled with a homogeneous liquid. The chemist takes samples from different parts of the liquid. Which can the chemists expect to find?

• The different samples will have the same melting and boiling points but different densities.

• The different samples will have the same, melting points, boiling points, and densities.

• The different samples will have the same melting points, but different boiling points and different densities.

• The different samples will have different melting points, boiling points, and densities.

The one-dollar U.S. presidential coin consists of a central core of pure copper that is surrounded by an alloy of four metals. A chemist wants to identify the solvent in the alloy. To do so, the chemist analyzes the components of the coin and collects the following data: The alloy consists of 12.0% zinc, 7.0% manganese, 77.0% copper, and 4.0% nickel. Which is the solvent in the alloy?

• zinc

• manganese

• copper

• nickel

A chemist analyzes an unknown liquid. The chemist takes samples from the top, middle, and bottom of the samples. Which observation would allow the chemist to reach the conclusion that the liquid could be a pure substance?

• All three samples have different boiling points.

• The top and middle samples have the same boiling point, which differs from the boiling point of the bottom sample.

• All three samples have the same boiling point.

• The middle and bottom samples have the same boiling point, which differs from the boiling point of the top sample

A student is given a 250-gram sample of seawater. She is asked to determine the percentage of dissolved solids in the sample. Which should she do first?

• filter the solids out of the sample

• expose the sample to magnetism

• evaporate the liquid from the sample

• freeze the sample