Chemistry 2.7-2.12 ck-12

When two or more different elements in a fixed proportion chemically combine, they form a(n) ___.

compound

A substance made up of only atoms of one type is called a(n) ___.

element

In ______, solids can be separated from liquids by heating the liquid and removing it.

evaporation

What separation technique is used to separate a dissolved solid from the liquid in which it is dissolved?

evaporation

Which element has the highest monetary value?

gold

A _____ mixture is a mixture in which the composition is not uniform throughout the mixture.

heterogeneous

A tossed salad is considered to be a _____.

heterogeneous mixture

Which of the following is/are homogeneous mixture(s)?

milk, liquid laundry detergent, vinegar, salt water

Which of the following is not a mixture?

Ammonia

What is the chemical symbol for gold?

Au

Change

Chemical

Butter is a mixture of proteins and fats that does not separate out when left alone. What type of mixture is butter?

Colloid

A substance which cannot split up into two or more simpler substances by physical or chemical methods is called a/an _____.

Element

A homogeneous mixture is a composition of two or more impure substances in a definite proportion, displaying non-uniform characteristics.

FALSE

A solution of salt and water is a heterogeneous mixture.

FALSE

An element can be easily converted into a simpler substance by any physical or chemical means.

FALSE

Gases form heterogenous mixtures with each other regardless of the identities or relative properties of the component gases.

FALSE

If two poisonous compounds are chemically combined, the resulting compound will definitely be harmful.

FALSE

Mixtures are considered to be pure substances.

FALSE

Mixtures can only be separated by a chemical change.

FALSE

Solutions are heterogeneous since the ratio of solute to solvent does not remain the same throughout the solution.

FALSE

Separation by physical size is ______.

Filtration

Which method of separation would be most effective to achieve the following diagram?

Filtration

A _____ mixture consists of two or more phases.

Heterogeneous

Which of the following contains a single phase? I. substance II. homogeneous mixture III. heterogeneous mixture

I and II only

Soil is a heterogeneous mixture. Which of the following statements best explains why?

It is unevenly mixed, so it does not have the exact same composition throughout the mixture.

Salt water is a homogeneous mixture. Which of the following statements best explains why?

It is uniformly mixed, so it has an even composition throughout.

"Mixture" is the term given to a material that contains at least two different substances.

TRUE

A compound can be broken down into simpler materials.

TRUE

A mixture that has a uniform composition and uniform properties in all its parts is called a homogeneous mixture.

TRUE

A true solution is a homogeneous mixture.

TRUE

Compounds have fixed compositions whereas mixtures vary in composition.

TRUE

Mixtures are physical combinations of two or more substances.

TRUE

The composition of a mixture is varied by altering the proportions of its constituents.

TRUE

The mixture is a physical blend of two or more components, each of which retains its own identity and property.

TRUE

Water is a homogeneous mixture which contains dissolved gases and minerals.

TRUE

What is the name of the reference that lists all the known elements?

The Periodic Table of Elements

Dissolving salt in distilled water creates a homogeneous mixture.

True

Dela is helping his Aunt Starr on an archeological dig. His aunt gives him a bucket containing sand, rocks, and artifacts. What is the best way for Dela to separate the sand from the other materials?

Use a screen to filter out the sand.

Can homogeneous mixtures be separated into their components?

Yes

Are elements considered to be substances?

Yes, because they have a definite composition

Distillation

a purification process where the components of a liquid mixture are vaporized and then condensed and isolated.

Filtration

a separation method used to separate out pure substances in mixtures comprised of particles some of which are large enough in size to be captured with a porous material.

compound

a substance that contains two or more elements chemically combined in a fixed proportion

Evaporation

a technique used to separate out homogenous mixtures where there is one or more dissolved solids

Which property is NOT used to separate a mixture?

ability to undergo a chemical reaction

A change that produces matter with a different composition is called a _____.

chemical change

The diagram shows two molecules (A and B) with different rates of travel on silica gel plate. Which method of separation would be most effective to separate a mixture of A and B?

chromatography

What method would likely be used to separate a mixture of colored inks?

chromatography

What separation technique involves passing the mixture through a medium in which the components move at different rates?

chromatography

_____ separates components in a mixture at different rates as they pass through a medium.

chromatography

Complete the sentence using one of the following words

chromatography, distillation, or evaporation.

How are most elements found in nature?

combined with other elements because elements are generally reactive

Complete the sentence using one of the following words

compound, mixture, or element. A(n) ____is the simplest form of matter that has a unique set of properties. : element

Which of the following is a viable method of separating gasoline from crude oil?

distillation

Pick the word that best completes the following sentence. A _______ mixture is a mixture in which the composition is uniform throughout the mixture.

homogeneous

Sugar dissolves completely in water to form a solution. This solution is a _____.

homogeneous mixture

Complete the sentence using one of the following words

homogeneous, heterogeneous, or uniform. Vegetable soup is an example of a : heterogeneous mixture.

Which element has been known for centuries?

iron

Chromatography

is the separation of a mixture by passing it in solution or suspension or as a vapor through a medium in which the components move at different rates.

When oil and water are mixed, two separate layers form. Each layer is called a(n) _____.

phase

In carbonated water, when carbon dioxide bubbles are thoroughly mixed into the water, they become invisible. What type of mixture is carbonated water?

solution

Which of the following is NOT a compound?

sulfur - S8

Lemonade is a murky yellow color. If you leave it sitting for a few minutes, you might need to stir it again before you drink it. What type of mixture is lemonade?

suspension

Which of the following are mixtures?

tea. Sand, air

element

the simplest form of matter that has a unique set of properties.

Which of the following statements about mixtures is FALSE?

they are all mixed uniformly and have an even composition throughout Substances must combine in specific proportions