Review Of Chemical Foundations

Question 1

Matter is anything that has _ and _

Answer 1

Mass and volume

Question 2

What are the two main ways of classifying matter?

Answer 2

Physical state and chemical constitution

Question 3

Name the three different physical states.

Answer 3

Gas, liquid, solid.

Question 4

Name the three different types of chemical constitutions.

Answer 4

Element, compound and mixture.

Question 5

What is the difference between homogeneous and heterogeneous mixtures?

Answer 5

Homogeneous mixtures have a uniform composition and heterogeneous mixtures have a non-uniform composition.

Question 6

Explain the differences between the three physical states of matter.

Answer 6

Solids are rigid and posses a definite shape.
Liquids flow and take the shape of its container.
Gases take both the shape and volume of its container.

Question 7

What is the difference between mass and weight?

Answer 7

Mass is a measure of the amount of matter in an object, whereas weight is the force that gravity exerts on the object.

Question 8

State the law of conservation of matter.

Answer 8

There is no detectable change in the total quantity of matter present when matter undergoes any physical or chemical changes.

Question 9

Define what an atom is.

Answer 9

An atom is the smallest part of an element that has the properties of that element and can enter into a chemical combination.

Question 10

Differentiate between a physical property and a chemical property.

Answer 10

A physical property is a characteristic of an element that is not associated with a change in chemical constitution, whereas a chemical property is the ability of a substance to undergo a reaction and convert from one type to another.

Question 11

Differentiate between physical and chemical change.

Answer 11

Physical change does not change the chemical identities of substances involved, whereas chemical change always produces one or more types of matter that differ from the matter present before the change.

Question 12

What is the difference between an extensive and intensive property?

Answer 12

An extensive property depends on the amount of matter present, an intensive property does not.

Question 13

Define accuracy.

Answer 13

Accuracy is when a measurement yields a result that is very close to the true or correct value.

Question 14

Define precision.

Answer 14

Precision is when measurements yield very similar results when they are repeated.

Question 15

Name three examples of physical properties.

Answer 15

Colour, solubility, density, hardness, melting and boiling points, electrical conductivity.

Question 16

Name three examples of chemical properties.

Answer 16

Flammability, toxicity, acidity.

Question 17

Name the three postulates of Dalton’s Atomic Theory.

Answer 17

All matter is composed of invisible atoms
An element is a type of matter composed of one type of atom, and each atom of a given type has the same properties
A compound is a type of matter composed of atoms of two or more elements chemically bonded in fixed properties.

Question 18

What is an isotope?

Answer 18

Atoms of the same element with different numbers of neutrons.

Question 19

Define 1 atomic mass unit.

Answer 19

1 atomic mass unit is 1/12 of the mass of one isotope of Carbon-12.

Question 20

Average atomic mass = …

Answer 20

Sum of i x (fractional abundance x isotopic mass)i

Question 21

Define molecular formula.

Answer 21

Chemical symbols to show types of atoms, followed by subscripts to show the number of each type of atom in the molecule.

Question 22

Define a structural formula.

Answer 22

A structural formula shows how the atoms are connected in a molecule.

Question 23

Define an empirical formula.

Answer 23

Indicated types of atoms and smallest whole number ratios of the number of atoms.

Question 24

What is meant by chemical nomenclature?

Answer 24

Systematic naming of compounds.

Question 25

State the law of multiple proportions.

Answer 25

When two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers.

Question 26

State the law of constant composition/definite proportions.

Answer 26

All samples of a pure compound contain the same elements in the same proportion by mass.

Question 27

1 amu = …

Answer 27

1.6605 x 10^-24 g

Question 28

Charge of an electron (e) = …

Answer 28

1.602 x 10^-19 C

Question 29

What is the mass of a proton?

Answer 29

1.0073 amu

Question 30

What is the mass of a neutron?

Answer 30

1.0087 amu

Question 31

atomic number (Z) =
mass number (A) =
A - Z =

Answer 31

Z = number of protons
A = number of protons + neutrons
A - Z = number of neutrons

Question 32

How do we know that an atom is electrically charged?

Answer 32

If the numbers of subatomic particles are not equal.

Question 33

What is an ion?

Answer 33

An electrically charged atom.

Question 34

Atomic charge = …

Answer 34

number of protons - number of electrons

Question 35

What is the difference between an anion and a cation?

Answer 35

An anion is an atom that has gained one or more electrons and is negatively charged.
A cation is an atom that has lost one or more electrons and is positively charged.