Chemistry and Matter

Question 1

Extensive

Answer 1

Describes matter depending on the amount of matter in the sample.

Question 2

Intensive

Answer 2

Describes matter depending on the type of matter, the contents (not the amount).

Question 3

Physical Properties

Answer 3

A property which can be observed and measured without changing the material’s composition

Question 4

Chemical Properties

Answer 4

• A property which can be observed by changing the composition of the material (after a chemical reaction)
• The ability to undergo a specific chemical change

Question 5

Plasma

Answer 5

Formed at high temperatures; ionized phase of matter

Question 6

Mixtures

Answer 6

A physical blend of two or more substances which have variable composition

Question 7

Heterogenous Mixture

Answer 7

A mixture which is not uniform in composition (ex. chocolate-chip cookie)

Question 8

Homogenous Mixtures

Answer 8

Same composition throughout; called “solutions” (powder-drinks, air)

Question 9

Solutions

Answer 9

• Homogeneous Mixture
• Includes a ‘solute’ and ‘solvent’
• Mixed by molecule to molecule, and can occur between any state of matter

Question 10

Phase

Answer 10

Any part of a sample with uniform composition of properties

ex. Homogeneous mixture consists of a phase, heterogeneous consists of 2+ phases

Question 11

Separating Mixtures:

Answer 11

Differences in properties can be used to separate mixtures

Question 12

Elements

Answer 12

Simplest kind of matter; cannot be broken down to have the same properties!
(One kind of matter)

Question 13

Compounds

Answer 13

• Substances which can only be broken down by chemical methods
• Made of 2+ atoms that are chemically combined
• Will have completely different properties if broken down

Question 14

Chemical Change

Answer 14

A change in which one or more substances is converted into new substances with change to composition.
Signs of a chemical change include heat and light.

Question 15

Precipitate

Answer 15

A solid that separates from solution (won’t dissolve)

Question 16

Signs of Chemical Change:

Answer 16

• Energy is absorbed or released (temp.)
• Color changes
• Gas production
• Precipitate
• Irreversibility

Question 17

Law of Conservation of Mass

Answer 17

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

Question 18

Symbols and Formulas:

Answer 18

Elements are represented by a 1 or 2 letter symbol; compounds are represented by a formula.
(ex. He = Helium; H20 = Water)

Question 19

Atomic Number

Answer 19

The number of protons in an atom (in the nucleus)!

Elements are different because they have different amounts of protons.

Question 20

Overall Charge:

Answer 20

All elements in nature have a neutral overall charge, therefore the number of protons equals the number of electrons.

Question 21

Mass Number

Answer 21

The number of protons and neutrons in the nucleus of an isotope. (Rounded atomic mass)

Question 22

Isotope

Answer 22

Element can vary based on the number of neutrons (and still be the same element).

Question 23

Electron Mass:

Answer 23

9.11 x 10^-28

Much less mass than protons and Neutrons

Question 24

Proton or Neutron Mass

Answer 24

1.67 x 10^-24

Majority of the Mass is in the Nucleus

Question 25

Periodic Law

Answer 25

When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

Question 26

3 classes of Elements

Answer 26

1. Metals - Electrical conductors, have luster, ductile, malleable (can be shaped or drawn out) 2. Non-Metals - Generally brittle and non-lustrous, poor conductors of heat and electricity (hard, but can snap or break) 3. Metalloids - Properties are intermediate between metals and nonmetals.

Question 27

Group of Elements

Answer 27

Group 1A - Alkali metals (very reactive; forms a base with water) Group 2A - Alkaline Earth metals (do not dissolve well; reactive; Earth metals and also form base with water) Group 7A - Halogens (wants one more electron) Group 8A - Noble gases (stable and don't react due to a full shell of electrons)

Question 28

Solute

Answer 28

Something which dissolves in the solvent (usually liquid) to make a solution.

Question 29

Solvent

Answer 29

Usually a liquid, does the dissolving of a solute to make a solution

Question 30

3 Classes of Mixtures

Answer 30

- Solutions - Colloid - Suspension

Question 31

Solution: 1. Ex. 2. Particle Type: 3. Particle Size: 4. Scatter Light? 5. Settle while standing? 6. ​Separate by filtration?

Answer 31

Always transparent, so that particles do not have to scatter light. 1. Ex. - Salt water, air 2. Particle Type - Ions, atoms 3. Particle Size - Small 4. Scatter Light? - No 5. Settle while standing? - No 6. ​Separate by filtration? - No

Question 32

Colloid: 1. Ex. 2. Particle Type: 3. Particle Size: 4. Scatter Light? 5. Settle while standing? 6. ​Separate by filtration?

Answer 32

A mixture where one of the substances is split into small particles that are dispersed throughout another substance. The small particles are called colloidal particles. 1. Ex. - Soot, fog 2. Particle Type - Small clusters 3. Particle Size - Medium 4. Scatter Light? - Yes 5. Settle while standing? - No 6. ​Separate by filtration? - No

Question 33

Suspension: 1. Ex. 2. Particle Type: 3. Particle Size: 4. Scatter Light? 5. Settle while standing? 6. ​Separate by filtration?

Answer 33

A heterogeneous mixture in which the solute particles do not dissolve in a liquid, and instead spread throughout the liquid. 1. Ex. - Muddy water, Flour, Paint, Chalk in water, etc... 2. Particle Type - Large clusters 3. Particle Size - Large 4. Scatter Light? - Yes 5. Settle while standing? - Yes 6. ​Separate by filtration? - Yes

Question 34

Tyndall Effect

Answer 34

Light passes through a colloid or suspension (particles scatter light).

Question 35

Emulsion

Answer 35

A mixture where two or more liquids are unblendable (such as oil and water), causing a liquid-liquid separation.

Question 36

Periodic Table:

Answer 36

Displays the symbols and names of the elements, along with information about the structure of their atoms. (Atomic Number and mass)

Question 37

Balanced Chemical Equation

Answer 37

- Atoms cannot be created or destroyed - Same number of elements on both sides of the equation Ex. 2_Na + 2_H2O --> _H2 + 2_NaOH

Question 38

The Skeleton Equation

Answer 38

A chemical equation which does not indicate how many elements; meaning NOT balanced. Ex. _Na + _H2O --> _H2 + _NaOH (Notice the Coefficients are missing)

Question 39

" (aq) " - after the chemical formula

Answer 39

Dissolved in water, an aqueous solution: NaCl (aq) is a salt water solution

Question 40

*arrow points up* - after the chemical formula

Answer 40

Used after a product showing that a gas has been produced.

Question 41

*arrow points down* - after the chemical formula

Answer 41

Used after a product indicating a solid has been produced

Question 42

Rules of Balance (Chemical Equations):

Answer 42

- Assemble the correct formulas for all the reactants and products, using "+" and "-->" - Count the number of atoms of each type appearing on both sides - Balance the elements on at a time by adding coefficients (the numbers in front) where you need more – save balancing H and O until LAST! (Oxygen is last) - Coefficient must be in the front! - Subscript cannot be changed, only coefficients, or it becomes a different compound.