CHM 111: Lecture 1 Review

Mixtures are a (?) combination of two or more substances

Physical

This is an example of a (?) composed of (?)

pure substance, a diatomic element

This is an example of a (?), composed of (?)

mixture, a monatomic element and a compound

This is an example of a (?), composed of (?)

pure substance, a monatomic element

This is an example of a (?), composed of (?)

mixture, two compounds

This is an example of a (?), composed of (?)

pure substance, a monatomic element

This is an example of a (?), composed of (?)

pure substance, a compound

This is an example of a (?), composed of (?)

mixture, a monatomic element and a diatomic element

This is an example of a (?), composed of (?)

mixture, different monatomic elements

Select all statements that are TRUE. 

a) Compounds and mixtures are the same thing.  

b) All molecules of the same compound are the same.

*For example:* all water molecules contain one oxygen and two hydrogen atoms bonded in the same way.  

c) All elements are pure substances.

d) All mixtures are pure substances.

e) Compounds can be separated into their elements through a CHEMICAL process. 

f) Elements must contain single atoms (monatomic) ONLY.

b) All molecules of the same compound are the same.

*For example:* all water molecules contain one oxygen and two hydrogen atoms bonded in the same way.  

c) All elements are pure substances.

e) Compounds can be separated into their elements through a CHEMICAL process. 

What is chemistry?

Chemistry is the study of matter, its properties, and the changes it undergoes. It is central to our fundamental understanding of many science-related fields.

What is matter?

Matter is the physical material of the universe. Everything is composed of matter. The state of matter is related to how it fills a container?

Which state of matter has a definite shape and volume and is not compressible?

Solid

Which state of matter has a distinct volume, assumes the shape of a container, and is not compressible?

Liquid

Which state of matter has no fixed volume or shape but can be compressed or expanded?

Gas

What is a pure substance?

Pure substances are matter with a fixed composition (Water (H2O), Nitrogen (N2), Oxygen (O2), and Gold (AU)).

What is a mixture?

A mixture is a physical combination of 2 or more substances in variable amounts (air, salt water, bronze). Mixtures contain a variable composition of two or more substance and exhibit the properties of the substances that make them.

What are atoms?

The smallest buildings blocks of matter.

What are elements composed of?

Many atoms of the same type.

What are molecules?

Molecules are 2 or more atoms chemically bonded together. Molecules are the smallest unit of a compound/element that retain the characteristics of that compound/element. All compounds are molecules, but not all molecules are compounds.

What are diatomic elements?

If atoms of a molecule are the same.

What is a compound element?

If atoms of the molecule are different.

What is a pure substance?

A pure substance is matter with a fixed composition.

What are allotropes?

Allotropes are two forms of the same element that differ in their chemical structure and properties.

What are the two types of mixtures?

Heterogeneous: composition varies or appearance varies or different phases. Composition is not uniform.

Homogeneous: same composition or appearance or same phase. Composition is uniform.

* Also called a solution

Classify each of the following as pure \n substances or a mixture. If a mixture, \n indicate whether it is homogeneous \n or heterogeneous.

a) Rice Pudding

b) Seawater

c) Magnesium

a) Heterogeneous mixture

b) Homogenous mixture (if any undissolved salt/sand → heterogeneous mixture).

c) Pure substance