chapter 1 1.1 what is chemistry? 1.2 describing matter 1.3 how is matter classified?

CHAPTER 1CHAPTER 1

1.1 What is Chemistry?1.2 Describing Matter1.3 How is Matter Classified?

• Describe ways in which chemistry is a part of your daily life.

• Describe that chemical and physical changes. • Describe the characteristics of the three common states of matter

• Identify the reactants and products in a chemical reaction.

• Able to make a list of evidence of chemical reaction.

Sec 1.1 What is Chemistry?

1. Make a list of all the chemicals that you can think of.

2. Which ones on that list could you live without?

3. Which ones on the list could you not live without?

Definition: Definition: What is Chemistry? What is Chemistry? Make your own definition.

• Chemistry (1947) – the science of substances: their structure, their properties, and the reactions that change them into other substances.

• Chemistry (1998) – the study of matter and the changes it undergoes.

• What is a chemical?

• A chemical is any substance that has a definite composition

Physical States of MatterPhysical States of MatterThree states of matter• Solid • Liquid• Gas

What is Matter?What is Matter?Everything that has mass and volume is called matter.

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All matter, regardless of state, undergoes physical and chemical changes. These changes can be

microscopic or macroscopic.

What kind of changes does matter undergo?

What is a physical change?What is a physical change?

A physical change occurs when the substance changes state but does not change its chemical composition.

For example: water freezing into ice, cutting a piece of wood into smaller pieces, etc. The form or appearance has changed, but the properties of that substance are the same (i.e. it has the same melting point, boiling point, chemical composition, etc.)

• Melting point• Boiling point• Vapor pressure• Color• State of matter

• Density • Electrical conductivity

• Solubility• Adsorption to a surface

• Hardness

Characteristics of Physical ChangesCharacteristics of Physical Changes

What are chemical changes?What are chemical changes?

A chemical change occurs when a substance changes into something new. This occurs due to heating, chemical reaction, etc. You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes. Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc).

• Reaction with acids• Reaction with bases (alkalis)

• Reaction with oxygen (combustion)

• Ability to act as oxidizing agent

• Ability to act as reducing agent

• Reaction with other elements

• Decomposition into simpler substances

• Corrosion

Characteristics of Chemical ChangesCharacteristics of Chemical Changes

Evidence of Chemical Change• the evolution of a gas• the formation of a precipitate• the release or absorption of energy• a change in temperature or the giving off of light energy

• a color change in the reaction system

Section Review

Page 9, Answer the questions #1-10