Section 1 Observing Chemical Change

Question 1

Matter and change

Answer 1

•changes in matter can be described in terms of physical changes and chemical changes

Question 2

Properties of matter

Answer 2

• Two properties of matter physical and chemical
  * physical properties = when solids melt, color , hardness, texture, shine, flexibility, ability to conduct heat and electricity
  * . Chemical properties= ability to rust or tarnish

Question 3

Changes of matter

Answer 3

• squashing a marshmallow is a physical change
  
  • the shape changes but the taste doesn’t
  • examples= bending, crushing, breaking, cutting, melting, freezing, boiling, condensing
  • chemical change= atoms get rearranged to form new substances

Question 4

Bonding and chemical change

Answer 4

• chemical changes occur when bonds break and new bonds form

Question 5

Evidence for chemical reactions

Answer 5

• chemical reactions involve changes in properties and changes in energy that you can observe.

Question 6

Changes in properties

Answer 6

• changes in properties means a new substance forms
• formation of solid, liquid, or gases
• moist bread dough that turns dry

Question 7

Changes in energy

Answer 7

• absorbs heat or liberate heat
• baking soda and vinegar mixed is a endothermic reaction
• occur when heat is constantly added
• frying an egg
• exothermic releases heat into nearby matter
• reaction between fuel and oxygen
• expansion