Test 1

Question 1

Name the three subatomic particles

Answer 1

Protons, neutrons & electrons

Question 2

What is the location and charge of each of these particles

Answer 2

Neutron- nucleus and has a neutral charge
Proton- nucleus and has a positive charge
Electrons are in the outer shells and have negative charge

Question 3

Atomic number equals

Answer 3

Number of protons

Question 4

Mass number equals

Answer 4

Number of protons and neutrons in the nucleus of an atoms

Question 5

What is the octet rule ?

Answer 5

Tendency of atoms to prefer 8 electrons in their outer (valence) shell

Question 6

What is a covalent bond? Provide example

Answer 6

Covalent bonds form when atoms share electrons to satisfy octet rule
Polar: electrons shared unequally H20 and non polar: electrons shared equally CH4
Always 2 non metals

Question 7

What is an ionic bond?

Answer 7

Ionic bonds form when atoms are held by the attraction between opposite charges
An ionic compound: NaCl & KBr

Question 8

Explain electronegativity

Answer 8

The strength of an atom to draw electrons towards themselves

Question 9

True or false: Atoms lose neutrons to form ions ?

Answer 9

False: Atoms can gain or lose electrons to become ions.
Loss of electron= + charge = cation
Gain of electron= - charge = Anion

Question 10

Definition of a buffer ?

Answer 10

A solution that resists major change in pH when small amounts of strong acid or strong basis are added.

Contains weak acid and its conjugate base

Question 11

For Quantitive measurements of concentration, what are units of measurements

Answer 11

Molarity number of moles of solute per kilogram of solvent. Mol/kg

Question 12

What are the types of molecular forces

Answer 12

Dipole- dipole (hydrogen bonds)
London dispersion forces

Question 13

What is the solubility of hydrocarbons such as alkanes in water?

Answer 13

Alkanes are not soluble

Question 14

What is the solubility if alcohols such as ethanol

Answer 14

Short chain alcohols are soluble in water. The longer the chain the lower the solubility

Question 15

What are intermolecular forces?

Answer 15

Attractive forces between neighbouring molecules

Question 16

Concentration measurement?

Answer 16

Is finding out how much of one substance is present in another. E.g blood glucose concentration is the amount of glucose present in the blood

Question 17

What is Solubility ?

Answer 17

Only substances that are similar to water can be dissolved in water. As water is polar, only substances that are polar & are able to form hydrogen bonds with water can dissolve in water

Question 18

What is an Acid?

Answer 18

Acids produce hydrogen ions H+

Question 19

What is a base

Answer 19

Bases produce OH- (hydroxide ions) in water

Question 20

Formula mass is?

Answer 20

The sum of the atomic masses of all the atoms present in the chemical formula (amu)

Question 21

Which changes will be observed if red blood cells are placed in a
a) Isotonic soloution
b) hypotonic solution
c) hypertonic solution

Answer 21

A) no change
B) hemolysis
C) crenation