Answer:
13 - D
14 - D
15 - C
Explanation:
for 13
A molecule is two or more atoms chemically combined
An example would be carbon dioxide which contains the two atoms, carbon and oxygen
Reasons its not the other answers:
Electrons, Protons and Neutrons are all parts of an atom therefore they cannot be classified as molecules.
For 14
Remember an atom is the most basic unit out of the units we are talking about
The answer would be D
Reasons its not the other answers
Water is considered to be a molecules as it contains two or more atoms (hydrogen and oxygen)
Air is considered to be a mixture as it contains oxygen and nitrogen which can be separated
Salt is considered to be a compound because salt is made up of two atoms (chloride and sodium) in which they are held up by an ionic bond
For 15
The answer would be C (III only)
Carbon hydrogen and oxygen all happen to by atoms
Reasons its not other answer choices:
Like stated previously water is considered to be a molecule therefore we can eliminate the other answer choices
Other notes:
Compounds and molecules both are combinations of two or more atoms however they are not to be mixed together
the main difference between compounds and molecules is how they are held together
Compounds are held together by ionic bonds while molecules are help up by covalent bonds
compounds and molecules are made up of atoms that cannot be separated
Mixtures - A mix of two or more substances that can be separated
