Chapter 4 Review (midterm)

Question 1

Why can a magnet separate iron atoms from an iron sulfur mixture but not from iron sulfide?

Answer 1

The iron has bonded with the existing sulfur and the magnetism cannot break those bonds. This new compound also does not have the same magnetic properties as the iron did.

Question 2

What was Empedocles contribution to atomic theory?

Answer 2

He proposed that all mater was composed of fire, air, water, and earth. The ratio determined the substance’s properties.

Question 3

What was Democritus’ contribution to atomic theory?

Answer 3

He proposed that all matter was made of infinitesimally small pieces of matter called atomos. (atoms) Atomos of stone were unique to stone and different from the atomos of other materials.

Question 4

What was Aristotle’s contribution to atomic theory?

Answer 4

He silenced Democritus’ ideas from being accessed for 2000 years. He also accepted Empedocles’ ideas and added that these 4 elements could be transformed into each other.

Question 5

What was Torricelli’s contribution to atomic theory?

Answer 5

He showed that air had “weight” and could push down on a column of liquid mercury

Question 6

What was Bernoulli’s contribution to atomic theory?

Answer 6

He developed a theory that air and other gases consisted of tiny particles that are too small to be seen and are loosely packed in an empty volume of space.

Question 7

What was Priestly’s contribution to atomic theory?

Answer 7

He experimented with red mercury calx and observed that it doesn’t only turn into mercury, but also a strange gas. This gas was oxygen.

Question 8

What was Lavoisier’s contribution to atomic theory?

Answer 8

He conducted experiments on oxygen and hydrogen and their bonding.

Question 9

What law did Lavoisier establish?

Answer 9

The law of Conservation of Mass

Question 10

What is the Law of Conservation of Mass?

Answer 10

Mass is not lost or gained during a chemical reaction.

Question 11

What was Dalton’s contribution to atomic theory?

Answer 11

He proposed his own atomic theory in A new System of Chemical Philosophy in 1803-1808

Question 12

What was Dalton’s atomic theory?

Answer 12

All matter is composed of indivisible particles called atoms; all atoms of a given element are identical, atoms of different elements have different properties; chemical reactions involve the combination of atoms, not the destruction; when elements react to form compounds they react in defined, whole-number ratios

Question 13

What was Boyle’s contribution to atomic theory?

Answer 13

He proposed a new definition of element as being a fundamental substance.

Question 14

What was Proust’s contribution to atomic theory?

Answer 14

he proposed that compounds have defined chemical formulas. He also proposed the Law of Definite Proportions

Question 15

What is the Law of Definite Proportions?

Answer 15

When certain elements react with other elements (to create a compound) they react in defined proportions

Question 16

What is the difference between an atom and an element?

Answer 16

An atom is a single particle. An element can be a collection of atoms.

Question 17

What is the difference between a molecule and a compound?

Answer 17

Compounds have multiple elements.

Question 18

Is straining cooked pasta from water a physical or chemical separation?

Answer 18

Physical

Question 19

Is using a fuel cell to separate water intro hydrogen and oxygen a physical or chemical separation?

Answer 19

Chemical

Question 20

Which type of matter (mixtures/compounds/elements) would need to be separated by physical methods?

Answer 20

Mixture

Question 21

Which type of matter (mixtures/compounds/elements) would need to be separated by chemical methods?

Answer 21

Compounds/elements

Question 22

What are the three states of matter?

Answer 22

Gases, liquids, and solids.

Question 23

Particles that are independent, widely separated, with no attractive forces between them, and fill the volume of the container are which state of matter?

Answer 23

Gases

Question 24

Strong attractions between particles lock them into a fixed arrangement describe properties of which state of matter?

Answer 24

Solids

Question 25

Particles that constantly make and break temporary attractions between each other, can slip past each other easily, and take the shape of their container describe properties of the particles of which state of matter?

Answer 25

Liquids

Question 26

What are pure substances?

Answer 26

Substances that have fixed compositions, one set of intrinsic physical properties and can be separated only by chemical means.

Question 27

What are mixtures?

Answer 27

Substances that have variable composition, varying physical properties depending on composition and can be separated by physical means.

Question 28

What are the two subsets of pure substances?

Answer 28

Elements and compounds

Question 29

What cannot be broken down into simpler substances by physical or chemical means? (the smallest particle of this is an atom)

Answer 29

ElementsWhat are made of elements in fixed mass rations and can be broken down into simpler substances by chemical means.

Question 30

What are the two types of mixtures?

Answer 30

Homogeneous and heterogeneous

Question 31

What is a homogeneous mixture?

Answer 31

These exist in only one phase and have uniform properties throughout the sample.

Question 32

What is a heterogeneous mixture?

Answer 32

These may exist in more than one phase and have variable properties in different parts of the sample.

Question 33

What is the difference between a pure substance and a mixture?

Answer 33

A pure substance has only one compound or molecule type in it. A mixture can have multiple. A mixture can be separated by both physical and chemical means. A Pure substance can only be separated through chemical means.

Question 34

Which technique would be useful to separate a mixture of sand and salt?

Answer 34

Filteration and distillation (less important)

Question 35

Which technique would be useful to separate a mixture of salt and water?

Answer 35

Distillation

Question 36

How does the law of definite proportions support an atomic model?

Answer 36

These defined atoms and their bonds with each other is how different substances can be considered unique

Question 37

How does the law of multiple proportions support an atomic model of matter?

Answer 37

When elements combine to form more than one compound, the ration of the mass of one element to itself combining with equal amounts of the other elements will be a whole number ratio.

Question 38

If a particle diagram has any order or organization, what is the state of matter?

Answer 38

SOLID

Question 39

What does the time temperature graph of water and ethanol look like?

Answer 39

The ethanol boils out at 80 deg. C so the water temperature waits for it then rises until it boils out at 100 deg. C

/
100 | _______________/
| /
| /
| /
80| _____________/
| /
| /
| /
| /
| /
| /
| /
| /
| /
|/
——————————————————————————–

Question 40

What is the boiling point of ethanol?

Answer 40

80 deg. C

Question 41

Is distillation a chemical change?

Answer 41

NO IT IS A PHYSICAL

Question 42

What can you do with a glowing splint?

Answer 42

Test the type of gas. Ignition = oxygen, goes out = carbon dioxide, popping sound (+ explosion) = hydrogen

Question 43

What was Avogadro’s hypothesis?

Answer 43

Equal volumes of 2 gases @ the same temperature and pressure contain = # of molecules

Question 44

How do you know which are the 2 atom molecules?

Answer 44

the rule of seven

Question 45

What is the rule of 7?

Answer 45

1) There are 7 diatomic molecules, 2) starts with element #7 (N), 3) They combine to form the # 7 on periodic table and add H.

Question 46

What are the 7 diatomic molecules?

Answer 46

Nitrogen, Oxygen, Florine, Chlorine, Bromine, Iodine, and Hydrogen

Question 47

When do noble gases react?

Answer 47

Only when they are forced to