2.2: Changes in Matter

Question 1

Define physical change

Answer 1

any changes where on the molecular level, nothing has changed (evaporation etc)

Question 2

Define nuclear change

Answer 2

changes within the nucleus (radioactivity)

Question 3

Define chemical change

Answer 3

change in the chemical bonds (atoms etc) within the fundamental entities and it usually stated in the chemical formula

Question 4

Define kinetic molecular theory

Answer 4

Atoms are constantly in motion, colliding with themselves and other objects

Question 5

How and why do chemical reactions occur?

Answer 5

When atoms chemical entities collide, they exchange or share electrons to obtain a more stable electron arrangement

Question 6

What are ways to know if a chemical change has occurred?

Answer 6

• colour change (different colour than starting product)
• odor change (different smell than reactants)
• state change
• energy change (heat, light, sound, or electricity absorbed or released)

Question 7

Define diagnostic test

Answer 7

short & specific lab test, with expected evidence and analysis, it is an empirical test for the presence of a new substance