States of Matter
What is an example of solids in real life?
Rock, table, metal
What does it mean to go through a physical change?
No new substances are made. It can go back to its original form.
What does it mean to go through a chemical change?
New substances are made. It can't go back to its original form.
What does the Law of Conservation of Mass mean?
It means matter cannot be created or destroyed.
It means that even when substances change form, their total mass (weight) remains unchanged.
What is a characteristic of a gas?
It fills up the space.
What is another term for physical changes?
Reversible change.
What is another term for chemical changes?
Irreversible change.
What is an example of Conversation of Mass in our daily life?
When we mix things or create things, their total mass is unchanged.
When you change liquids to gas, what is it called?
Evaporation
True or false: Baking bread is a physical change.
False
True or false: Baking bread is a chemical change.
True
When you break a chocolate bar into pieces, will the total mass change?
No, it will be the same unless you eat some!
When you change liquids to solids, what is it called?
Freezing
Give an example of physical change other than water.
Chopping wood, cutting paper
Give an example of chemical change other than cooking or baking.
Fire burning, rusting metal
When you burn wood, does the total mass change?
No, unless you fail to capture the gas (smoke).
When you change solids to gases, what is it called?
Sublimation
Why is boiling water a physical change?
Because the water that you boil can evaporate into gas and that gas can cool down back into liquid, going back to its original form.
Why is digesting food in your stomach a chemical change?
Because your stomach acid is breaking down the food you ate so your body can absorb it easily. You also cannot undigest food.
When can the total mass change?
If the new substances created is spilled (solid or liquid) or floats away (gas), the mass can change.