Twenty Questions

Changes in Matter– Test Review

Twenty Questions

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1. What is matter?

Anything that takes up space and has mass

2. What is a molecule?

It is made up of two or more atoms joined together

3. A substance that is made up of just one kind of atom is called

An element

4. Give 3 examples of an element.

Oxygen, sodium, hydrogen, iron, gold, silver, carbon, calcium (anything on the periodic table of elements)

5. Describe the particles in a solid, liquid and gas.

The particles in all 3 states are always moving but…Solid – the particles are locked in place, although they are still vibratingLiquid – the particles are close to each other but they move quickly and slide past each otherGas – the particles are far apart and move quickly

6. What is the difference between a chemical change and a physical change?

Physical change is a change that does NOT result in a new substance.

Chemical change is a change that results in the formation of new substances

7. Give 3 examples of a physical change.

Tearing paper, ice melting, carving a tree, cutting paper, sugar dissolving in tea,

8. Give 3 examples of a chemical change.

Toast burning, bread baking, eggs rotting, an object rusting, an object burning,

9. Ari is having a hard time deciding if something has gone through a chemical change or physical change. Give him 3 clues that he can use to help him decide if a chemical change has occurred.

Color change Smell New physical property (i.e. rust, burnt toast) Substance is given off (smoke is released when

something burns) Heat is given off

10. What is the difference between physical properties and chemical properties?

Physical properties are traits that involve a substance by itself (what does the substance look like? How would you describe it?)

Chemical properties are properties that involve how a substance interacts with (or reacts) other substances

11. Give examples of physical properties and examples of chemical properties.

Example: DeskPhysical properties – color (tan), hardness (hard), state at room temperature (solid), Chemical properties – reacts with heat (burns if temp is hot enough); does not react with air; does not react with many other substances

Example: WaterPhysical properties – color (colorless), smell (odorless); state at room temperature (liquid),Chemical Properties - hydrogen and oxygen react with each other to form water; many substances react with it (i.e. many substances dissolve in it)

12. What is the difference between boiling and condensing?

Boiling is when a substance changes from a liquid to gas

Condensing is when a substance changes from a gas to a liquid

13. Julie heated water until it became a gas. Which term identifies this change?

boiling

14. Which of the following is NOT an element… iron, gold, steel or silver?

Steel

15. What is it called when a solid changes directly into a gas?

sublimination

16. What is a compound and give an example of a compound?

A substance made up of two or more different elements that have chemically combined

Examples:

1) water – Hydrogen and oxygen combined

2) salt – sodium and chlorine

3) rust – iron and oxygen combined

4) carbon dioxide – carbon and oxygen

17. When you dissolve sugar in water, is that a physical or chemical change? Explain.

A physical change. Once the water evaporates, you are left with sugar.

18. All matter is made of _________

Atoms

19. A car engine uses gasoline and oxygen. The exhaust given off has water and the gas carbon dioxide. Was this a chemical reaction? Explain.

Yes. Two new substances – water and carbon dioxide – were produced

20. Explain why the burning of wood is a chemical change. List as many clues as you can.

Wood is brown Ashes are gray Wood gives off heat and light as it burns