Physical and Chemical Changes

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Physical and Chemical Changes
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Matter

• Matter anything that has volume or mass.
  
• Atoms are the smallest unit of matter!
• Volume anything that takes up space
• Mass the amount of matter that something
  is made of

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MASS

• Mass
• Measured in grams with a balance

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Volume

• Liquid Volume
• measured in liters
• Meniscus the curve that
• you see at the liquids
• surface used to measure
• the volume

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Volume

• Solid Volume
• Measured in cubic meters (m3)
• Cubic means having 3 dimensions

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Remember

• Inertia tendency of all objects to
  resist any change in motion
• More Mass Greater Inertia
• harder to move an object with a large mass
• harder to stop an object with larger mass once
  moving

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A. Matter Flowchart
MATTER
yes
no
Can it be separated by physical means?
Homogeneous Mixture (solution)
Heterogeneous Mixture
Compound
Element
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B. Pure Substances

• Element
• matter composed of identical atoms
• EX copper

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B. Pure Substances

• Compound
• matter composed of 2 or more elements in a fixed
  ratio
• properties differ from those of individual
  elements
• EX salt (NaCl)

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C. Mixtures

• Non-specific combination of 2 or more pure
  substances.

Two Types of Mixtures
Homogeneous Mixture even distribution of
components EX saline solution
Heterogeneous Mixture uneven distribution of
components EX granite
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A. Physical Property

• A characteristic of matter that can be observed
  or measured without changing the identity of its
  matter.
• can be used to separate mixtures
• EX density, color, odor, mass and volume

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Chemical Property

• A characteristic that indicates whether a
  substance can undergo a specific chemical change.
• EX flammability, reactivity

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Physical Change

• Physical changes occur when matter changes its
  property but not its chemical nature.
• Physical changes could include a change in
  texture, shape, size, color, odor, volume, mass,
  weight, and density.

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Physical Change

• Remember!
• properties remain the same
• reversible
• can be used to separate mixtures

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Physical Change
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Chemical Change

• Chemical changes are changes matter undergoes
  when it becomes new or different matter.
• To identify a chemical change look for signs such
  as color change, bubbling and fizzing, light
  production, smoke, and presence of heat.

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C. Chemical Change

• Remember!
• properties change
• irreversible
• Signs color change, formation of a gas/solid,
  release of light/heat

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Chemical Change

• A chemical change occurs when fireworks are used.
  Fireworks are made of metals such as magnesium
  and copper. These change chemically as they
  light up the sky.

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Density

• Density describes how much mass is in a given
  volume of a material.

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Density

• Solids, liquids and gases are matter, so they all
  have density.

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Determining Density

• To find the density of a material, you need to
  know the mass and volume of a solid sample of the
  material.
• Mass is measured with a balance or scale.
• Use the displacement method or calculate the
  volume.

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Density Problems
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What is my Density?
Complete the following questions on a separate
sheet of paper as a part of your homework
assignment.

• Mass
• 1. 500g
• 2. 300g
• 3. 25g

• Volume
• 50ml
• 15ml
• 5cm3