Physical or Chemical Changes
Is making scrambled eggs a physical or chemical change? Explain
Chemical Change-anytime you cook food that automatically tells you that a chemical change has taken place. You also know because it cannot be reversed.
During melting, are molecules moving closer together or further apart? Are molecules starting to move faster or slower?
During melting the molecules are speeding up and moving further apart.
What happens to atoms during a chemical change?
The atoms are rearranged to form new substances.
When a substance changes state, is that a physical or chemical change?
Physical change- a change of state doesn't affect things at the molecular level.
Which does not dissolve in water: sugar, salt, or oil?
oil
What happens to a substance during a physical change?
Only the form or appearance is altered, no new substances are formed.
Melting-solid changes to liquid. Freezing-liquid changes to solid. Evaporation-liquid changes to gas. Condensation- gas changes to liquid. Sublimation- solid changes directly to gas.
How can you determine if something has undergone a chemical change?
If something is cooked/burned, if light or sound or heat is produced, if a gas is produced (fizzing/bubbling), if a precipitate forms, or there is an unexpected color change.
How can you determine if something has undergone a physical change? Explain
If a substance has only changed shape or size, if it went through a phase change, if the change can be reversed, etc.
Python -it has a backbone.
Are nails rusting a physical change or chemical change? Explain.
Chemical change-a metal reacts with oxygen to form rust, which is a new substance.
During freezing are molecules moving closer together or further apart? Are molecules starting to move faster or slower?
During freezing the molecules are slowing down and moving closer together.
Which is not a physical change? A. glass breaking B. paper burning C. ice melting D. sugar dissolving
B. Paper burning-a new substance is formed (ash), carbon dioxide and water vapor are produced.
Is chopping wood a physical or chemical change? Explain.
Physical change. The wood is only changing its size and shape; it is still wood; nothing new is formed.
A jellyfish has no vertebrae or gills. Is it really a fish?
No.
Is making Kool-Aid a physical or chemical change? Explain.
Physical Change- You are just physically mixing together the sugar, powder, and water; nothing new is formed.
During evaporation, are molecules moving closer together or further apart? Are molecules starting to move faster or slower?
During evaporation the molecules are speeding up and moving further apart.
How does a chemical change differ from a physical change?
A chemical change produces new substances with properties different from those of the original substances.
Is twisting a wire a physical or chemical change? Explain.
Physical change- only the shape is being changed; the wire is still wire.
What are three main states of matter?
Solid, liquid, gas.
Is burning leaves a physical or chemical change? Explain.
Chemical Change. A new substance is formed (ash); a gas is produced (carbon dioxide); water vapor also forms.
During condensation, are molecules moving closer together or further apart? Are molecules starting to move faster or slower?
During condensation the molecules are slowing down and moving closer together.
Which is not a chemical change? A. leaves turn color B. fruit ripens C. silver tarnishes D. food coloring dissolves in water
D- food coloring dissolves in water-the food coloring and water are just physically mixing together-no new substances are formed.
Why are phase changes examples of a physical change?
Because a phase change does not affect things at the molecular level (ex: when water is frozen it is H2O; when it is liquid it is H2O; when it is gas it is H2O-doesn't change).
What does the formula CO2 stand for?
Carbon Dioxide