Chapter 2

Question 1

Chemical reaction

Answer 1

a transformation that modifies nature and it’s properties of matter

Question 2

hints of a chemical reaction

Answer 2

• change of colour
• gas release
• change in temperature
• emission of light
• formation of a solid

Question 3

Chemical reaction examples

Answer 3

• combustion ( a campfire )
• photosynthesis ( plants transform carbon dioxide, water and salt minerals into sugar and oxygen )
• digestion ( transformation of food into nutriments that the body can absorb )
• décomposition ( composting )

Question 4

Matter

Answer 4

The matter is everything that has a MASS and a VOLUME

Question 5

atoms

Answer 5

Matter is composed of atoms
( they can’t be divided, broken, created or destroyed )
They are presented as a ball

Question 6

Atoms united

Answer 6

atoms unite and create molecules.

Question 7

Molecule

Answer 7

a molecule is made up of at least one kind of identical or different elements

Question 8

element

Answer 8

an element can be presented in the form of a single atom or as a molecule made of different elements

Question 9

French scientist

Answer 9

Antoine Lavoisier

Question 10

French scientist famous phrase

Answer 10

nothing is lost, nothing is created, everything is transformed

Question 11

conservation of matter

Answer 11

when the mass of substances before and after the transformation stay the same

mass before = mass after