ECM

Question 1

What is a compound?

Answer 1

A compound is two or more different types of atoms chemically bonded

Question 2

What is a mixture?

Answer 2

A mixture is two or more substances not chemically bonded

Question 3

What is the compound of copper and bromine?

Answer 3

Copper bromide

Question 4

What is the compound of calcium and oxygen?

Answer 4

Calcium oxide

Question 5

What elements are in the compound potassium iodide?

Answer 5

Potassium and iodine

Question 6

What elements are in the compound strontium nitride?

Answer 6

Strontium and nitrogen

Question 7

What is the:
a) ratio of atoms
b) name of elements in compound
of magnesium oxide - MgO?

Answer 7

a) 1 atom of magnesium : 1 atom of oxygen
b) magnesium, oxygen

Question 8

What is the:
a) ratio of atoms
b) name of elements in compound
of sodium nitride - Na3N?

Answer 8

a) 3 atoms of sodium : 1 atom of nitrogen
b) sodium, nitrogen

Question 9

What is a molecule?

Answer 9

A molecule is a substance where two or more non-metal atoms are chemically bonded (these can be the same or different type of atom)

Question 10

Is H2O a compound, element or a molecule? (Can be two)

Answer 10

Compound & molecule

Question 11

Is Cl2 a compound, element or a molecule? (Can be two)

Answer 11

Element & molecule

Question 12

Is Ar a compound, element or a molecule? (Can be two)

Answer 12

Element

Question 13

Is NaCl a compound, element or a molecule? (Can be two)

Answer 13

Compound

Question 14

Is a molecule an element or a compound? Why?

Answer 14

A molecule can be both an element or a compound. If the molecule contains two or more of the same type of atom then it’s an element of a molecule. If the molecule contains two or more of the different type of atom chemically bonded then it’s a compound of a molecule.

Question 15

What are diatomic elements?

Answer 15

Diatomic elements are elements with two or more atoms.

Question 16

Why are diatomic elements found in pairs?

Answer 16

Diatomic elements are always found in pairs because they are unstable on their own.

Question 17

What are the diatomic elements? Give their formula too

Answer 17

hydrogen (H2), nitrogen (N2), oxygen (O2), fluorine (F2), chlorine (Cl2), bromine (Br2), iodine (Il2)

Question 18

What are pure substances?

Answer 18

Pure substance are substances made up of only one type of particle.

Question 19

(T or F) Elements and compounds are pure substances.

Answer 19

True

Question 20

(T or F) Mixtures are impure substances.

Answer 20

True

Question 21

Can a compound also be a molecule? Explain your answer and give an example.

Answer 21

A compound can also be a molecule. A compound is a substance containing 2 or more different types of atoms chemically bonded and a molecule is made up of 2 or more non-metal substances chemically bonded. Therefore, if the substances in the compound were non-metal that it would also be a molecule. An example of this is H2O (hydrogen and oxygen are both non-metal, different atoms and are chemically bonded)

Question 22

What are two differences between a mixture and a compound?

Answer 22

• in a mixture the substances are not chemically bonded whereas in a compound they are
• the reactants of a compound have different properties compared to the products following the chemical reaction whereas a mixture has the properties of its constituent parts