Midterm 1 (In Class Notes)

Question 1

Provide an example of a pure substance

Answer 1

A pure substance (also known as a pure compound) would be sodium chloride (table salt) - NaCl

Question 2

What is an example of not a pure compound?

Answer 2

If you were to add table salt into water H20 - you can then evaporate the water and the table sale will still be there.

Question 3

How can you characterize ionic compounds?

Answer 3

You can use melting points to characterize ionic compounds. Example: Firemen can collect different products to characterize how a hot a fire was.

Question 4

What is the IUPAC?

Answer 4

International Union of Applied and Pure Chemistry. They update the periodic table of elements.

Question 5

Who created the periodic table of elements?

Answer 5

Dmitri Mandeleev in 1860’s?

Question 6

Wha isa good property of metal?

Answer 6

Good conductors as electrons are very close to each other.

Question 7

What is the volume in litres of a 3.9m3 container (hint 1L = 1000cm3)

Answer 7

3,900L

Question 8

Rules of significant numbers?

Answer 8

1. If a “0” is located between non-zero numbers then they are significant. example being 101 - has 3 significant numbers.
2. If the “0” is at the beginning of a number with a decimal point, these are NOT significant –> 0.0015 - has only 2 significant numbers
3. “0” at the end of a number with a decimal point is considered significant –> 25.20 - has 4 significant number.
4. “0” at the end of a number not containing a decimal point –> 100 - has three significant numbers.

Question 9

How do you write 100 with one, two, and three significant figures?

Answer 9

1. 1 x 10(power of 2)
2. 1.0 x 10(power of 2)
3. 1.00 x 10 (power of 2)

Question 10

How do you write 12,000 with 6 significant figures?

Answer 10

1.20000 x 10(power of 4) —–> 10,000 x 1.2 = 12,000

Question 11

How do your write 0.000120 in scientific notation?

Answer 11

1.2 x 10(power of - 4) —>Using the number 1.20 and moving the decimal four places to the left.

Question 12

List in chronological order the scientists who developed the idea of the atom?

Answer 12

1. Democritus ~ 440B.C. (Greek) - Grains of sand

2.Pierre Gassendi (1600’s) - reopened the discussion of the atom to debate and did not contradict Christian beliefs.

3. Antoine Lavoisier (1600) (French) - Conversion mass (mass off element will be the same regardless of state) and combustion
4. Proust (1700’s): Created the law of definite proportions: Combinations of atoms create specific molecules with specific property.
5. Dalton - created atomic theory and the law of multiple proportions. each molecule has its exact proption.
6. Thompson = –> Negative charged electrons
7. Rutherford = –> Positive charged electrons (1/1000 rays went through the foil but one bounced back)
8. Chadwick -> Found the remainder of the neutron (neutrally changed)

Question 13

What is the term for N20

Answer 13

Laughing gas (nitrous oxide)

Question 14

What is the term for NO2

Answer 14

Nitrogen dioxide (what is burned in our engines)

Question 15

What is Mario’s favourite periodic table?

Answer 15

Electron, Quark Up, Quark down, Neutrinos

Question 16

What are the different types of carbon isotopes?

Answer 16

C12 (stable with 6 neutrons and 6 protons), C13 (stable 1 extra neutron), C14 (NOT stable - radioactive with 2 extra neutrons - Becomes N14

Question 17

What is the Pauli exclusion principle?

Answer 17

No two electrons in an atom can have the same four quantum numbers. SO –> If one electron in an atom has quantum numbers n=1, l=0, m1 = 0, and Ms = +1/2 - no other electron can have these quantum numbers.

Question 18

What is Hunds rule?

Answer 18

In 1927 Friedrich Hund stated that the lowest-energy arrangement of electrons in a subhsell is obtained by putting electrons into separate orbitals of the subshell with the same spin before pairing electrons.

Question 19

What causes sub-shells to be at different level n’s?

Answer 19

Electron-Electron repulsion?

Question 20

What are some elements that do not follow the rules of electron configuration?

Answer 20

Copper (Cu)

Question 21

What is Aufbau’s Principle?

Answer 21

You need to build configurations from the ground up. (1s and then 1s + 2s and then 1s + 2s + 2p and then 1s +2s + 2p + 3s)– etc

Question 22

What are degenerate orbitals?

Answer 22

Electron orbitals having the same energy levels

Question 23

What is unique about Manganese in regards to its electron configuration?

Answer 23

It goes straight to “d’ which all have a single electron

Question 24

What are the different periodic trends?

Answer 24

1. Atomic radius: Bonding atomic radius increase as we go down the column, but decreases from left to right (same row)
2. Cation X+ will be smaller as they have lost an electron
3. Anions X- will be bigger as they have gained an electron

Question 25

What is the isoelectric series of ions??

Answer 25

They all have the same number of electrons and the size goes down with increase in nuclear charge --> Example: O2- > F- > N > Na+

Question 26

Give 2 principals of core electrons?

Answer 26

1. They block energy from outer electrons 2. Effective in screening outer electrons (but electrons in the same shell do not screen each other)

Question 27

What type of energy is needed to remove electrons in the gas phase?

Answer 27

Oxidization

Question 28

What is electron-affinity and energy change when adding on electrons?

Answer 28

Upon adding an electron forming anion X- will cause changes in electron. The electron-affinity is the need to add an electro because you have an affinity for them.

Question 29

What occurs during a polar vortex?

Answer 29

No O3 is being made. When O3 is being made, heat is released from the making of strong bonds allowing for heat. This is absent because there is no atomic oxygen which is made when light "heats" up and breaks O2. So air pressure (Pv) drops then so does pHT (Temperature) Pressure (Pv) drops = hRT (temp) drops In the spring, when there is more sun (energy) the ice melts and turns to liquid H20. It gives off heat and the vortex breaks.

Question 30

What is electro-negativity?

Answer 30

The ability for an atom in a molecule to attract an electron to itself

Question 31

Guelph Hard Water Example

Answer 31

Guelph had hard water which is made up of CaCO3. We buy water softener (NaCl+) which causes a cation exchange. The salt displaces the Ca2+ so it doesn't reach the pipes using electrostatic forces.

Question 32

How are pressure (Pv) and Temperature (hRT) related?

Answer 32

When the pressure goes up the temperature goes up and when pressure goes down, so does temperature.`

Question 33

What is the Lewis Dot Structure Hydrofloric Acid (HF)?

Answer 33

Question 34

What is the Lewis Dot Structure Water (H20)?

Answer 34

Question 35

What is the Lewis Dot Structure for NH3 (Ammonium)?

Answer 35

Question 36

What is the Lewis Dot Structure for CH4 (Methane)

Answer 36

Answer: H H - C - H H

Question 37

What is the Lewis Dot Structure for CO2 (Carbon dioxide)

Answer 37

Question 38

What is the Lewis Dot Structure for CO2 (Carbon dioxide)

Answer 38

Question 39

Is O3 a greenhouse gas and why?

Answer 39

Yes, technically O3 (ozone) is a green house gas. This is because it traps infared radiation coming from the earth in the atmosphere and heats it.

Question 40

What is the Lewis Dot Structure for PCl3?

Answer 40

Question 41

What is the Lewis Dot Structure for CH2Cl2

Answer 41

Question 42

What is the Lewis Dot Structure for HCN?

Answer 42

Question 43

What is the Lewis Dot Structure for CN-?

Answer 43

Question 44

What is the Lewis Dot Structure for NO+

Answer 44

Question 45

What. is the Lewis Dot Structure for BrO3-

Answer 45

Question 46

What are resonance structures?

Answer 46

Resonance structures are a set of two or more Lewis Structures that collectively describe the electronic bonding of a single polyatomic species.

Question 47

What are the different possible resonance structures for NCS-

Answer 47

Question 48

What are the different resonance structure for NCO

Answer 48

Question 49

What are the resonance structures for NO3

Answer 49

Question 50

What are the resonance structures for SO3

Answer 50

Question 51

What are the resonance structures for SO3(2-)

Answer 51

Question 52

Which has the shorter sulfur-oxygen bonds? SO3 or SO3(-2)

Answer 52

SO3 has shorter sulfur-oxygen bonds compared to SO3-2; this is because SO3 has a higher bond order due to its neutral charge, resulting in stronger and shorter bonds with oxygen atoms compared to the negatively charged SO3-2 ion where the electrons are more distributed, leading to longer bonds.w

Question 53

What are the resonance structures for HCO2 -

Answer 53

Question 54

What are the resonance structure for CO3 (2-)

Answer 54

Question 55

Define the electron configuration of ACTINIUM-225 (Ac^89) and LUTETIUM-177 (Lu71) from the d block ?

Answer 55

Actinium-225 (Ac *89) = [Rn] 6d1 7s2 Lutetium 117 (Lu71) = [Xe] 4f145d16s2.

Question 56

HOW MANY ANTIPROTONS IN NUCLEUS OF ANTI-HELIUM-4?

Answer 56

2

Question 57

What kind of bonds hold together the compounds (praseodymium orthoscandate)

Answer 57

Held together by ionic bonds.

Question 58

Based on the graph in reading 3 what subshell the additional electron located in the Cl- (chlorine negative one) ion that is observed in Fig. 4.?

Answer 58

3p

Question 59

Are electron geometry and molecular geomerty diferent?

Answer 59

Yes, they can be different as it depends on the lone pair of central atoms.

Question 60

In regards to molecular geometry, what do regions mean?

Answer 60

Regions are the series of lone pair, single bonds, double bonds, or triple bonds that surround electrions

Question 61

What are the typical geometry of the regions?

Answer 61

Two Regions: Linear or 180 degrees Three Regions: Trigonal Planar or 120 degrees Four Regions: Tetrahedral 109.5 degrees

Question 62

What are the geometry of NH4+ and NO3-

Answer 62

NH4+ has four regions meaning it is tetrohedrayl NO3- has 3 regions meaning it is trigonal

Question 63

What is the electro geometry of nitrogen tri-iodide?

Answer 63

The electron geometry of NI3 is tetrahedral as we do not consider the lone pairs present in the molecule. The molecular geometry is trigonal pyramidal as one lone pair is on the nitrogen atom.

Question 64

What is the shape of the SO2 molecule?

Answer 64

Bent - Trigonal Planar

Question 65

Do noble gases make covalent bonds?

Answer 65

No there is 0 electronegativity so they make ionic compounds.