Domains, Phases, Matter, classification, Physical and chemical properties, Measurements, Mathematical treatment

Question 1

What is accuracy?

Answer 1

The agreement of a particular value with the true value
(or accepted value)

Question 2

What is precision?

Answer 2

the degree of agreement among several measurements of the same quantity.

Question 3

What are 3 rules for counting SF in a given number?

Answer 3

Non-zero integers always count as sig.figs. 345 m

Captive zeros always count as sig.figs. 16.07 mL

Leading zeros do NOT count as sig.figs; they indicate order of magnitude. ex: 0.0486 g has 3 SF

Question 4

Why do we want to be precise in our rounding?

Answer 4

to make sure our numerical results honestly reflect the level of uncertainty in the raw data used.

Question 5

Density

Answer 5

A quantifiable physical property of substances

Question 6

Formula of density

Answer 6

mass/volume

Question 7

What are the 5 steps in problem solving?

Answer 7

1. Interpret the question.
   ▪ Determine what the problem is asking.
2. Develop a plan of attack.
   ▪ Identify key principles.
   ▪ Sketch diagram / write chemical equation. ▪Organizeinformation: knownvs.unknown; +units. ▪ Break problem into simpler ones – take logical steps.
3. Execute the plan.
   ▪ Show all units – do they yield desired units at end ? ▪ Don’t skip steps (& don’t round off prematurely).
4. Check your answer.
   ▪ Common sense – is it a reasonable number ? ▪ Verify number of significant figures.

Question 8

Sterling silver is a solid solution or “alloy” of silver (Ag) and copper (Cu). If a piece of a sterling silver necklace has a mass of 105.0 g and a volume of 10.12 mL, calculate the mass percent of silver in the necklace.
Assume that the volume of silver present plus the volume of copper present equals the total volume.

Question 9

What are the 3 states of matter?

Answer 9

Solid
Liquid
Gases

Question 10

What are the characteristics of Solids? (3)

Answer 10

▪ rigid shape, fixed volume.
▪ external shape can reflect particles’ arrangement.
▪ behaviour is reasonably well understood.

Question 11

What re the characteristics of liquids? (2)

Answer 11

▪ fluid shape, but fixed volume.
▪ behaviour is not well understood
(i.e., complicated).

Question 12

What are the characteristics of Gases?

Answer 12

▪expand to fill their container.
▪ behaviour very well understood
(& simple).

Question 13

What is an Element?

Answer 13

Pure substance that cannot be subdivided into any other substances via physical or chemical methods (details about methods soon…)

Question 14

What is the building block of any Element?

Answer 14

It is composed of only ONE kind of atom

Question 15

What is a compound? (2)

Answer 15

▪ pure substance that requires chemical means to be further subdivided
▪ cannot separate into parent elements via physical separation methods

Question 16

What is the building block of a component? (2)

Answer 16

composed of ≥ 2 elements’ atoms/ions in a fixed ratio

smallest group of atoms / ions that retains BOTH the composition & characteristics of the compound

Question 17

Give an example of a chemical mean used to break down compounds into their constituent elements.

Answer 17

Electrolysis:
pass high current through liquid water to decompose it:

Question 18

What is a covalent compound?

Answer 18

MOLECULE = atoms bonded together into a discrete unit

Question 19

What is an Ionic compound?

Answer 19

IONS = charged (+,-) atoms or groups of atoms, which pack in ratios that give neutral combinations

Question 20

The figures below represent four different samples of gas-phase matter.
The figures below represent four different samples of gas-phase matter.

Question 21

Energy can be classified as _________or__________

Answer 21

Energy can be classified as Potential or Kinetic

Question 22

What is Potential Energy (PE)?

Answer 22

energy associated with position

Question 23

What 4 types of PE?

Answer 23

• gravitationalE
• chemical energy
• electrostaticE
• nuclear energy

Question 24

Give an example of Gravitational PE.

Answer 24

an object held at a height, waterfalls.

Question 25

Give an example of Chemical PE.

Answer 25

energy stored in molecules, due to bonds between atoms

Question 26

Give an example of Electrostatic PE.

Answer 26

energy due to attractions between charged or partially charged particles

Question 27

Give an example of Nuclear PE.

Answer 27

energy associated with attractions between nuclear particles (released via fission, fusion)

Question 28

What is Kinetic Energy (KE)?

Answer 28

energy associated with motion

Question 29

What are 4 types of KE?

Answer 29

- Mechanical energy - Thermal Energy - Electrical Energy - Acoustic Energy

Question 30

What is Mechanical energy?

Answer 30

movement of a macrosopic object (e.g.,ball)

Question 31

What is Thermal energy?

Answer 31

Motion at the particulatel evel

Question 32

What is electrical energy?

Answer 32

movement of electrons in a conductor

Question 33

What is Acoustic energy?

Answer 33

compression-type wave motion

Question 34

What is the Kinetic Molecular Theory?

Answer 34

Matter consists of particles in constant motion

Question 35

Is KE proportional or inversely proportional to Temperature?

Answer 35

Proportional Higher Temp = Faster Motion

Question 36

What causes particles to stick together?

Answer 36

Forces of attraction (Chem 206)

Question 37

Why is matter usually solid at low Temp.?

Answer 37

K.E. is low thus attractive forces seem large between particles

Question 38

Why is matter usually liquid or gas at high Temp.?

Answer 38

Higher K.E. thus the particles can overcome attractions

Question 39

How does density change with T?

Answer 39

as tempature decreases the density increases

Question 40

Why is that density increases at lower temperatures?

Answer 40

When particles’ kinetic energy decreases (i.e., at lower T), attractive forces between particles are more significant e.g. particles move closer together and volume decreases

Question 41

When discussing density and temperature, what information must be specified?

Answer 41

* Density * Volume

Question 42

Why is Water ice iunusual?

Answer 42

unlike water ice, most solids sink in their liquids

Question 43

What is a phase change?

Answer 43

Change of state

Question 44

What is a Physical change?

Answer 44

change in organization of particles, NOT composition

Question 45

What are characteristic propreties?

Answer 45

Temperatures at which changes

Question 46

What occurs in terms of energy when particles move closer together?

Answer 46

energy released as heat

Question 47

What occurs in terms of energy when particles move further apart together?

Answer 47

an energy input will be required

Question 48

How can we identify a substance (if it’s pure)?

Answer 48

▪ Colour, odour ▪ State of matter: Gas? Liquid? Solid? ▪Appearance: Shape? Powdered? Crystalline? Transparent? ▪ Melting point, boiling point, sublimation ability ▪ Solubility: How much will dissolve? In what will it dissolve? ▪ Electrical conductivity: conductor vs. insulator? ▪Malleability: easilydeformed? ▪Ductility: easilydrawnintoawire? ▪ Magnetic properties: attracted to magnetic field? ▪ Viscosity: for liquids: thick or thin? Does it flow easily? ▪ Density: mass per unit volume

Question 49

How could we classify matter in terms of mixtures vs. pure substances? (slide 41)

Question 50

What techniques could be used to separate heterogeneous mixtures? (3)

Answer 50

by filtration by distillation chromatography

Question 51

Describe the filtration method for seperating heterogeneous mixture. Slide 41

Question 52

Describe the distillation method for seperating heterogeneous mixture.

Question 53

Describe the chromatography method for seperating heterogeneous mixture.

Answer 53

- To determine how many components are in mixture, - To test purity, or before attempting large scale separation

Question 54

The beaker contains a solution of a nonvolatile blue solid, copper sulfate (CuSO4), dissolved in water. Which method below would separate the mixture into its two components, such that you would end up with a pure sample of each substance? A. Distillation B. Filtration C. Chromatography D. Sublimation

Answer 54

A. Distillation

Question 55

Physical change is the change in _______________________________________________ because ____________________________

Answer 55

Physical change is the change in organization of atoms/molecules/ions because there is a change in interactions between molecules

Question 56

[48] Chemical change is the change in____________________________________________ because ___________________________________________

Answer 56

Chemical change is the change in composition of atoms/molecules/ions because there is a rearrangement of bonds between atoms/ions

Question 57

In a physical change, the identity of substance(s) is:

Answer 57

unchanged

Question 58

In a chemical change, the identity of subtances is:

Answer 58

Changed

Question 59

Give 3 real life examples of physical changes.

Answer 59

melting butter dissolving sugar in water boiling water

Question 60

Give 3 real life examples of chemical changes.

Answer 60

burning butter digesting sugar reacting water with Na(s)

Question 61

Both physical and chemical changes involve:

Answer 61

transfers of energy: release (or absorption) of HEAT or LIGHT

Question 62

Give 4 examples of substances that react with oxygen and/or water.

Answer 62

▪ Combustion -- of wood, gasoline “organic materials” ▪ Rusting -- of iron ▪ Tarnishing -- of silver (is not an example!!) ▪ Hardening -- of cement

Question 63

Consider the following statements about sulfur (S), a yellow non-metallic element. 1) Sulfur is produced commercially by injecting steam into underground sulfur deposits to melt it. 2) It is then carried by the steam to the surface, where the sulfur separates from the water after cooling. 3) Sulfur burns in oxygen to form a choking gas, SO2, which reacts with water to form acid rain. Which statements describe(s) a chemical reaction ? A. Statement 2 only. B. Statement 3 only. C. Statements 1 & 2. D. Statements 2 & 3. E. All of them.

Answer 63

B

Question 64

[51] A student slowly heats some water (H2O) in a beaker. When the water reaches 30 C, bubbles begin to form on the walls of the beaker and eventually float to the surface. At 100 C, bubbles form rapidly throughout the water as it boils. Which option (A-E) describes the composition of the bubbles at the two temperatures?

Answer 64

C