Physical change
It alters the form or appearance of matter but does not turn any substance in the matter into a different substance.
A substance that undergoes a physical change is still ______________________
the same substance after the change
What are the 3 states of matter?
solid, liquid, gas
When water evaporates into a gas is it still water? Why?
No.
A physical change occurred and it turned into water vapor.
Dissolving is an example of a ___________ change.
Physical
Other examples of physical changes are ___________, __________, ___________, and ____________.
bending, crushing, breaking, and chopping
Chemical change
A change in matter that produces one or more new substances.
In some chemical changes, a single substance breaks down into __________ or ____________ substances.
Give an example.
Two or More
Example: Hydrogen peroxide breaks down into water and oxygen gas when it's poured on a cut on your skin.
In other chemical changes, two or more substances __________ to form __________ substances. Give an example.
Combine
Different
Example: Photosynthesis
How is a chemical change different than a physical change?
Unlike a physical change, a chemical change produces new substances with new and different properties.
How does a fingerprint become visible during a forensic investigation?
The vapors react with sweat or other body chemicals in a fingerprint to form a white powder making the print visible.
Explain the chemical change of combustion. Give examples.
The chemical change that occurs when fuels, such as natural gas, candle wax, or wood, burn in air.
Example: Gas oil or coal burning in a surface.
Explain the chemical change of Electrolysis. Give examples.
Use of electricity to break a compound into elements or simpler compounds.......
What is the law of conservation of mass?
The fact that matter is not created or destroyed in any chemical or physical change.
Explain what happened in the picture on page 25.
It shows that while a chemical change is going on, atoms are neither lost or gained, only rearranged.
Energy
The ability to do work or cause change.
How are energy and matter related?
Energy and matter are both conserved in a chemical change. Energy is never created or destroyed.
Temperature
A measure of how hot or cold something is.
Do the particles of gas in the warm outside air have a greater energy of motion than the particles of air inside the cool building?
Yes
Thermal energy
The total energy of the motion of all of the particles in an object.
The amount of thermal energy an object has is related to its _________.
Temperature
How does thermal energy naturally flow?
From warmer matter to cooler matter.
When is thermal energy released or absorbed?
When matter changes.
Melting of ice is a _____________ change.
Endothermic.
Endothermic change
A change in which energy is absorbed.
_____________ is a chemical change that releases thermal energy and light and is also an _____________ change.
Combustion
Exothermic
Exothermic change
Releases energy
Chemical energy
The energy stored in the chemical bonds between atoms.
Where is chemical energy stored?
Foods, fuel, and cells of your body.
Give an example of chemical energy.
When you ride a bike up a hill, chemical energy from foods you ate changes into energy of motion.
Chemical change of Oxidation.
Give an example.
Combination of a substance with oxygen.
Example: Rusting of an iron fence.
Chemical change of Tarnishing.
Give an example.
Slow combination of bright metal with sulfur or another substance.
Example: Tarnishing of brass.
What is law of conversation of mass?
the fact that matter is not created or destroy in any chemical or physical change
What is chemical energy?
Energy stored in chemical bonds