Chem Unit Test 1

Question 1

What would be the state of an ionic compound at 25 degrees celsius?

Answer 1

solid

Question 2

What would be the state of a molecular compound at 25 degrees celsius?

Answer 2

solid, liquid, or gas.

Question 3

Give an example of a solid at room temperature molecular compound?

Answer 3

Sugar C12H22O11

Question 4

Give an example of a liquid at room temperature molecular compound?

Answer 4

Water H2O

Question 5

Give an example of a gas at room temperature molecular compound?

Answer 5

Oxygen O2

Question 6

Are the melting points of ionic compounds high or low?

Answer 6

high

Question 7

Are the melting points of molecular compounds high or low?

Answer 7

low

Question 8

Describe the conductivity of ionic compounds.

Answer 8

They are electrolytes (conduct an electric current when dissolved in water). Not conductive in solid form.

Question 9

Describe the conductivity of molecular compounds.

Answer 9

They are nonelectrolytes. (Except acids and bases).

Question 10

Describe the solubility of ionic compounds.

Answer 10

Most are soluble.

Question 11

Describe the solubility of molecular compounds.

Answer 11

Most aren’t soluble.

Question 12

What happens when a molecular compound melts?

Answer 12

Its intermolecular forces break.

Question 13

What are intermolecular forces?

Answer 13

The forces between the atoms in a molecule.

Question 14

Why do ionic compounds have higher melting points than covalent compounds?

Answer 14

Because ionic bonds are much stronger than intermolecular forces.

Question 15

Who discovered electronegativity?

Answer 15

Linus Pauling.

Question 16

Why are ionic compounds stronger than covalent compounds?

Answer 16

Because opposite charges attract.

Question 17

What is electronegativity?

Answer 17

The tendency of an atom to attract electrons in a covalent bond.

Question 18

What does the electronegative difference have to be in order to indicate a non polar covalent compound?

Answer 18

0

Question 19

What does the electronegative difference have to be in order to indicate a polar covalent compound?

Answer 19

more than 0 less than 1.7.

Question 20

What does the electronegative difference have to be in order to indicate an ionic compound?

Answer 20

over 1.7.

Question 21

What do the dipole moments point to?

Answer 21

The element with the greater electronegativity.

Question 22

What does the length of the dipole moment correspond to ?

Answer 22

The electronegativity.

Question 23

How does one tell if a molecule is polar judging by the diagram?

Answer 23

If it is asymmetrical. (all atoms around central atom are not the same or lone pairs around central atom).

Question 24

What two factors do the melting points of molecular substances depend on ?

Answer 24

1. The type of intermolecular force.

2. The size of the molecule.

Question 25

What are the 3 types of intermolecular forces?

Answer 25

1. H-bonds (polar) 2. Dipole-dipole (polar). 3. London forces (polar and non-polar)

Question 26

How to tell if a polar molecule has Hbonds or dipole dipole forces?

Answer 26

If the hydrogen is bonded to O, N, or F it has Hbonds. If not, it has dipole-dipole forces.

Question 27

How does the size of the molecule affect the strength of london forces?

Answer 27

London forces become stronger as molecular size increases.

Question 28

Which typically have have higher boiling points: polar or non-polar compounds?

Answer 28

Polar compounds. Because they have Hbonds or dipole-dipole forces ALONG with the london forces.

Question 29

Why do ionic solutions conduct electricity?

Answer 29

When it dissolves in water, the ions separate.

Question 30

Why don't molecular solutions conduct electricity?

Answer 30

Because the molecules separate but no ions are produced.

Question 31

What lets something conduct electricity?

Answer 31

The movement of ions.

Question 32

give an example of a word equation for NaCl.

Answer 32

Sodium + Chlorine = Sodium chloride.

Question 33

Give an example of a skeleton equation for NaCl.

Answer 33

Na + Cl = NaCl.

Question 34

Write the balanced equation for NaCl.

Answer 34

2Na + Cl2 = 2NaCl.

Question 35

What is the Law of Conservation of Mass?

Answer 35

In any chemical reaction, the mass of the products is equal to the mass of the reactants.

Question 36

What is the synthesis reaction?

Answer 36

A + B = AB

Question 37

What is the decomposition reaction?

Answer 37

AB = A + B

Question 38

What is the Single deplacement reaction?

Answer 38

A + BC =AC + B

Question 39

What is the Double deplacement reaction?

Answer 39

AB + CD = AD + CB.

Question 40

What does an acid separate into?

Answer 40

A non-metal oxide + water.

Question 41

What does a base separate into?

Answer 41

A metal oxide + water.

Question 42

What does a metal hydroxide separate into?

Answer 42

Metal oxide + Water.

Question 43

What does a metal nitrate separate into?

Answer 43

Metal nitrite + oxygen.

Question 44

Is methane polar or non-polar?

Answer 44

NON-POLAR!!!!!!!!!!

Question 45

When do you use the electronegative difference to determine if a covalent compound is polar/non-polar/ionic.

Answer 45

When the compound only contains two elements.

Question 46

Which are stronger: covalent bonds or H-bonds?

Answer 46

Covalent bonds.

Question 47

What is a covalent bond?

Answer 47

A chemical bond that involves the sharing of electron pairs between atoms.