Question

Which of these particles is the smallest?
*
an atom
a nucleus
a proton
a compound

Answer 1

Matter can undergo physical and chemical changes. A physical change is a change of matter from one form to another without a change in chemical properties. Which process is an example of a physical change?
*
iron rusting in rain
candle burning in jar
salt dissolving in water
chicken cooking in oven

Answer 2

Alison mixes baking soda and vinegar in a clear glass container. She places a blue balloon over the mouth of the container. Which condition tells Alison that a chemical change is taking place?
*
The balloon fills and expands.
The mixture is cloudy in appearance.
The balloon gets lighter blue as it expands.
The container holds a mixture of a solid and liquid.

Answer 3

The starting products of a chemical reaction are 92.6g of Hg and 7.4g of oxygen (O) gas. A scientist hypothesizes that the mass of the final product will be 100g total. What law supports the scientists hypothesis?
*
Law of Conservation of Elements
Law of Conservation of Energy
Law of Conservation of Mass
Law of Conservation of Atoms

Answer 4

Sean fell while riding his green bicycle last year. He bent the fender and scratched the paint down to the metal. Sean’s bicycle was outside all winter and now is beginning to rust where the fender is damaged. Which evidence tells Sean that a chemical change is taking place on his bike?
*
The paint is scratched.
The metal fender is bent.
The metal is beginning to turn orange.
The bicycle sat in the weather all winter.