States of Matter
Give an example of a solid, a liquid and a gas.
Answers vary.
Is matter conserved during a physical change?
Yes
Is matter conserved during a chemical change?
Yes
Most packages of food coloring just have 4 colors. How do bakers make more colors for icing?
Mixing two or more colors will make new colors.
When we made Goop in class--did it have properties of a solid or a liquid?
Both
Give an example of how heating and cooling affects water.
Heating: enough heat would make it boil and then evaporate.
Cooling: Cooling to freezing would turn it to ice.
In a physical change, is a new type of matter formed?
No
How do you know if a chemical change has occurred?
A new substance will have formed (color change, formation of a precipitate, formation of a gas--bubbles, odor change )
Give two examples of mixtures.
Salad, trail mix, cereal....
Solubility and Flexibility
The state of a substance depends on it's _________.
Temperature
Give an example of a physical change.
Cutting paper, mixing ingredients in a bowl, melting ice, shredding cheese...
Why is baking a cake a chemical change?
Because a new substance is formed, and the change cannot be undone.
What is one way to make a solid dissolve faster?
Stir it, heat it, grind it into smaller pieces...
In the Chemical Changes lab, you mixed either sugar, salt, or baking soda with either water, lemon juice, or vinegar. The baking soda and the vinegar made a chemical change/reaction. How do you know?
A new substance (gas/bubbles) was formed.
How are the molecules in a solid different than in a gas?
The molecules in the solid are packed tightly together and only slightly vibrate to maintain the shape of the solid. The molecules in a gas have a lot of space between them and move freely to fill up the container.
How does cold temperature affect the air inside a balloon?
The gas molecules move closer together, the volume of air shrinks, and the balloon gets smaller.
Is a mixture a chemical change?
No
How can you separate salt from water?
Evaporation
Why did the magnet pull the iron filings out of the mixture you separated last week?
Iron is magnetic.
Why does ice float?
Frozen water is less dense that liquid water, so ice floats.
How can you use the melting point and boiling point of a substance to identify it?
Each substance has a different melting and boiling point. If you know the melting point and boiling point, you can identify the substance.
What does the Law of the Conservation of Matter say?
With any physical or chemical change, the total mass of the matter stays the same.
What is a major difference between mixtures and solutions?
Name all 5 parts of the mystery mixture you separated in class.
peppercorns, aquarium rocks, red sand, plastic unit cubes, iron filings