Chemistry: Mixtures and Solutions

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Questions and Answers

What is the chemical symbol for magnesium?

Mg (correct)

MgO

What happens to magnesium when it is heated?

It dissolves in the air.

It turns into a gas.

It burns with a bright light. (correct)

It melts into a liquid.

What substance is formed when magnesium burns in oxygen?

Magnesium oxide (correct)

Magnesium hydroxide

Magnesium sulfate

Magnesium chloride

Which of the following statements is true about elements?

Elements are made up of one type of atom. Signup and view all the answers

What distinguishes a compound from an element?

Compounds are formed from a combination of different elements. Signup and view all the answers

What is formed when magnesium atoms bond with oxygen atoms?

Molecule of magnesium oxide Signup and view all the answers

What is the composition of one molecule of magnesium oxide?

One magnesium atom and one oxygen atom Signup and view all the answers

What type of change occurs when magnesium is burned?

Chemical change Signup and view all the answers

What are the characteristics of a solution?

Homogeneous with uniform composition. Signup and view all the answers

Which of the following is an example of a colloid?

Milk Signup and view all the answers

What effect do colloidal particles exhibit when light passes through them?

Tyndall effect Signup and view all the answers

How do suspensions differ from solutions?

Suspensions have non-uniform composition. Signup and view all the answers

Why can compounds not be separated by physical methods?

They are composed of elements that are bonded chemically. Signup and view all the answers

Which of the following best describes a suspension?

Particles settle over time and are cloudy in appearance. Signup and view all the answers

Which of these is NOT a characteristic of colloids?

Particles settle over time. Signup and view all the answers

What distinguishes a mixture from a compound?

Mixtures can be separated by physical means. Signup and view all the answers

What defines a pure substance?

A matter made up of only one kind of particle that is chemically bonded Signup and view all the answers

Which of the following correctly describes an element?

It cannot be broken down into anything simpler by chemical means. Signup and view all the answers

What is the difference between a compound and a mixture?

A compound involves chemical bonding between elements, whereas a mixture consists of physically combined substances. Signup and view all the answers

Which of the following is an example of a homogeneous mixture?

Sugar dissolved in water Signup and view all the answers

A suspension is best described as which of the following?

A heterogeneous mixture in which some particles settle upon standing. Signup and view all the answers

What is a characteristic of a heterogeneous mixture?

The composition and properties are non-uniform. Signup and view all the answers

What role does a solute play in a solution?

It is the substance that dissolves in a solvent to form a homogeneous mixture. Signup and view all the answers

Which of the following substances is considered a compound?

Hydrogen chloride Signup and view all the answers

Study Notes

Colloids

Colloids are mixtures with particles larger than solutions but smaller than suspensions.
Examples: milk, mayonnaise, jelly, fog
Colloids appear homogeneous to the naked eye, but are heterogeneous at a microscopic level.
Particles do not settle over time.
Exhibit the Tyndall effect (scattering of light).
Cannot be separated by ordinary filtration.

Solutions

Solutions are homogeneous mixtures.
Solute particles are evenly distributed and do not settle over time.
Cannot be separated by filtration.
Examples: saltwater, vinegar, air.
Solutions are transparent; light passes through without scattering.

Suspensions

Suspensions are heterogeneous mixtures.
Particles are large enough to settle out over time.
Can be separated by filtration.
Examples: muddy water, sand in water, flour in water.
Suspensions are opaque or cloudy, and particles scatter light.

Elements

Elements are pure substances consisting of only one type of atom.
Cannot be broken down into simpler substances by chemical means.
Examples: magnesium (Mg), oxygen (O).

Compounds

Compounds are formed when two or more different elements are chemically combined.
Have properties distinct from the elements that compose them.
Cannot be separated by physical methods like mixtures.
Examples: water (H2O), magnesium oxide (MgO).

Mixtures

Mixtures are combinations of two or more substances that are physically combined.
Can be separated by physical means.
Two main types: homogeneous and heterogeneous.

Homogeneous Mixtures

Composition is uniform throughout.
Different particles are not visible.
Examples: saltwater, sugar dissolved in tea.

Heterogeneous Mixtures

Composition is non-uniform.
Different particles are visible.
Examples: salt and pepper, sand and water.

Burning Magnesium

A piece of magnesium ribbon is a pure element, consisting only of magnesium atoms (Mg).
When heated in a flame, magnesium reacts with oxygen from the air.
This chemical reaction results in the formation of magnesium oxide (MgO), a compound.
Magnesium oxide is a white powder that is different from the original magnesium ribbon.
This demonstrates how elements can combine to form new substances with different properties.

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Description

Explore the fascinating world of mixtures with this quiz on colloids, solutions, and suspensions. Understand their unique properties, examples, and behaviors. Test your knowledge on how these mixtures differ from pure substances and their characteristics.