science chapter 8 part 2

Question 1

what are molecules?

Answer 1

molecules are groups of two or more atoms chemically combined together

Question 2

True or False?
The atoms in the molecule can be the same or different

Answer 2

true.

Question 3

when is a molecule of an element formed?

Answer 3

a molecule of an element is formed when atoms of the same element chemically joined together to form a molecule

Question 4

examples of a molecule of an element?

Answer 4

hydrogen (H2), Sulfur (S8) and oxygen (O2)

Question 5

when is a molecule of a compound formed?

Answer 5

a molecule of a compound is formed when atoms of different elements chemically join together to form a molecule.

Question 6

examples of molecule of a compound?

Answer 6

carbon dioxide (CO2) and water (H2O)

Question 7

what is a molecule?

Answer 7

a molecule is the smallest unit of matter which can exist by itself and retain all its chemical properties.

Question 8

what do molecules tend to be?

Answer 8

symmetrical.

Question 9

what is the shape of a water molecule? (useful for when asked to draw)

Answer 9

mickey mouse

Question 10

what is a way that a molecule can be represented as?

Answer 10

using chemical formula

Question 11

what does the chemical formula tell us?

Answer 11

the chemical formula tells us the kind of atoms as well as the number of each kind of atoms present in the molecule

Question 12

what is something to note about chemical symbols?

Answer 12

many symbols have 2 letters. only the first alphabet is a capital letter, the second alphabet is a small letter.

Question 13

what so some compounds contain?

Answer 13

some compounds may contain the same elements but have entirely different properties from one another

Question 14

examples of when some compounds may contain the same elements but have entirely different properties from one another

Answer 14

both carbon monoxide (CO) and carbon dioxide (CO2) contain the same elements carbon and oxygen but they have different properties. the difference in their properties lies in the number of atoms present in each molecule.

Question 15

what is the labelling for the chemical formula of H2O?

Answer 15

H - symbol for hydrogen atom
O - symbol for oxygen atom
2 - represents 2 hydrogen atoms, the number has to be written as a subscript.

Question 16

what is the labelling for Al 2 (CO3) 3 ?

Answer 16

2 aluminium atoms
3 carbon atoms (1 x 3 that is outside the bracket)
9 oxygen atoms (3 x 3 that is outside the bracket)