Term
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Definition
Physical Changes
Chemical Changes. |
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Term
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Definition
| A physical change may cause a change in form or state, but not in substance. |
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Term
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Definition
| A chemical change occurs when a substance changes into one or more new substances with different properties. |
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Term
| Characteristics of Physical Change |
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Definition
Physical change
reversible (usually)
no new substance forms
properties do not change
energy change may occur, but may not be noticed |
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Term
| Characteristics of Chemical Change |
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Definition
Chemical change
irreversible (usually)
new substance forms (for example, gas or solid)
new set of properties (for example, colour)
energy change may occur (for example, heat or light is given off, or energy is absorbed) |
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Term
| Identifying Chemical and Physical Change |
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Definition
| The challenge of distinguishing between physical and chemical changes is that you can only observe the large visible changes. |
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Term
| The Kinetic Molecular Theory |
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Definition
The kinetic molecular theory is the idea that matter is made from moving
invisible particles. |
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Term
| Explaining Changes of State |
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Definition
| changing from a subtance to another is made possible by th e addition or removal of energy. |
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Term
| Explaining Dissolving and Density |
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Definition
During dissolving the warmer water particles move quickly, they are capable of separating the sugar particles at a higher rate.
As substances are heated, the increased motion of the particles causes them to spread apart, resulting in an increase in volume, called expansion.
Since density equals mass/volume, when the volume increases and the mass stays the same,the density decreases. |
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