Unit 1 Lesson 1-2 Quiz Review

This picture represents: 

• Element

• Compound

• Mixture of Elements

• Mixture of Compounds

Answer explanation

The picture represents a compound because it consists of two or more elements chemically bonded together, forming a substance with distinct properties, unlike mixtures which retain individual properties of their components.

A gold bar is an example of a.....

• pure element

• pure compound

• heterogeneous mixture

• homogeneous mixture

Answer explanation

A gold bar is made entirely of gold, which is a pure element. It consists of only one type of atom, making it distinct from compounds or mixtures.

An element is made up of only one kind of _____.

• isotope

• plastic

• atom

• metal

Answer explanation

An element consists of only one type of atom, which is the basic unit of matter. Isotopes refer to variations of atoms, while plastic and metal are materials made from various atoms, not single types.

Which among the following is an element?

• brass

• bronze

• silver

• stainless steel

Answer explanation

Among the options, silver is the only pure element. Brass and bronze are alloys, while stainless steel is a mixture of metals. Therefore, silver is the correct answer as it is a distinct chemical element.

Which term represents the particle that is formed when 2 or more atoms come together as one?

• atoms

• elements

• molecules

• compounds

Answer explanation

The term 'molecules' refers to particles formed when two or more atoms bond together. While 'atoms' are the basic units, 'elements' are pure substances, and 'compounds' are specific types of molecules made of different elements.

What is the term used for the substances that are formed when 2 or more atoms from differing elements come together?

• atoms

• elements

• molecules

• compounds

Answer explanation

The term for substances formed when two or more atoms from different elements combine is 'compounds'. Atoms are the basic units, while molecules can be made of the same or different elements, but compounds specifically refer to different elements.

TRUE OR FALSE:

Every compound is a molecule and every molecule is a compound.

• TRUE

• FALSE

Answer explanation

The statement is FALSE because while all compounds are molecules (composed of two or more atoms), not all molecules are compounds. For example, O2 (oxygen gas) is a molecule but not a compound.

Carbon is considered an element while carbon dioxide is considered a compound. This is because carbon dioxide is –

• a gas at room temperature.

• made of two different elements.

• given off by green plants.

Answer explanation

Carbon is an element, while carbon dioxide (CO2) is a compound because it consists of two different elements: carbon and oxygen. This distinction is fundamental in chemistry.

Surface tension is the property of water in which...

• water molecules at the surface tend to stick together.

• water spills easily.

• water tends to be see-through.

Answer explanation

Surface tension occurs because water molecules at the surface are attracted to each other more strongly than to the air above, causing them to stick together. This is why the correct answer is that water molecules at the surface tend to stick together.

Define the term soluble.

• Can dissolve in water

• Cannot dissolve in water

• Partially dissolves in water

Answer explanation

The term 'soluble' refers to a substance's ability to dissolve in water. Therefore, the correct choice is 'Can dissolve in water', as it accurately defines what it means for a substance to be soluble.