CHE 1V - Midterm

what’s the order of the seven types of radiation from highest energy to lowest energy

1) gamma

2) x-ray

3) UV

4) visible

5) IR

6) microwave

7) radio

which of the seven types of radiation are able to break chemical bonds

everything before IR

• gamma

• x-ray

• UV

• visible

how do you calculate the number of n in an isotope

mass of the isotope - number of protons in the element

what are the products for a complete combustion rxn vs an incomplete combustion rxn

• complete: CO₂ + H₂O

• incomplete: CO or CO₂ + H₂O

how do temps and pressure change through the diff layers of the atmosphere

temp (alternates):

• troposphere: decrease

• stratosphere: increase

• mesosphere: decrease

• thermosphere: increase

• exosphere: big fluctuations

pressure:

• decreases with altitude

what is the conversion for metric ton to gigaton, megaton, and kg

1 gigaton = 10⁹ metric tons

1 megaton = 10⁶ metric tons

1 metric ton = 10³ kg

on average, how many miles per gallon does a car get

25 miles/gallon

Name the five IDEAL geometric shapes and their angles in accordance to their bonds

= 2: linear (180^o)

= 3: trigonal planar (120^o) —> 2 comes before 3

= 4: tetrahedral (109.5^o) —> 4 looks like 9

= 5: trigonal bipyramidal (120^o, 90^o)

= 6: octahedral (90^o)

what are the four groups of observed geometric shapes and their corresponding number combos

1) stay same group (from 3-6, oct + all T’s except TP and t-shape)

• TPL: 3-0

• tetra: 4-0

• TBP: 5-0

• Oct: 6-0

2) belt group (all 2s + 3-2; one even # + one odd # for each)

• BE: 2-1, 2-2

• Linear: 2-0, 2,3

• T: 3-2

3) supple snake spy group (ID: 42-41-51)

• SPL: 4-2

• SS: 4-1

• SPY: 5-1

4) TP group (3-1 gives TP energy)

• TP: 3-1

what is the conversion factor for cm³ to mL

1 cm³ = 1 mL

what are the six groups on the PT and what are their corresponding group numbers

1) alkali metals (1)

2) alkaline earth metals (2)

3) pnictogens (15)

4) chalogens (16)

5) halogens (17)

6) noble gases (18)

what two elements are naturally polyatomic ions and how many are there

1) P₄

2) S_⁸

how can you tell which elements are naturally diatomic by looking at the PT

start at N and draw a “7” that ends at I (and then add H)

answer the following for s, l, g: takes shape of container, fills container, definite volume, definite shape

S: no, no, yes, yes

L: yes, no, yes, no

G: yes, yes, no, no

what’s the equation to find number of neutrons in a neutrally charged atom AND an isotope

mass # - # p

Looking at the letter symbol for an element, where does the atomic number go and where does the mass number go: top left or bottom left

atomic number: bottom left

mass number: top left

what is the only element with no neutrons

hydrogen

what are the equations to find accuracy and precision

accuracy:

• absolute error = true value - measured value

precision:

• relative error = (abs error / true value) x 100

if uncertainty is NOT given, what do you assume

assume that uncertainty is equal to ± 1

how do you get from % to ppm and ppm to %

• % to ppm: multiply by 10,000

• ppm to %: divide by 10,000

define parts per hundred compared to parts per million

• pph: expresses concentration of gas in % out of 100 molecules

  • so x / 100

• ppm: measurement of gas concentrations out of 1,000,000 molecules)

  • so x / 1,000,000

what is the three phase process of ozone CREATION

phase 1: O₂ —uv-c—> 2O

phase 2: two possibilities

• a) O₂ + O —> O₃

  • O₃ —uv-b—> O₂ + O

• b) O₂ + O —> O₃

  • O₃ + O —> 2O₂

phase 3: O₂ repeats cycle

what is the five step process of ozone DEPLETION by chlorine

• CFC → CCl₂F + Cl

  • UV light breaks apart the CFC, releasing a chlorine atom.

• 2Cl + 2O₃ → 2ClO + 2O₂

  • The chlorine atoms react with ozone, destroying it and forming chlorine monoxide (ClO).

• 2ClO → ClOOCl

  • Two ClO radicals combine to form the chlorine peroxide dimer.

• ClOOCl → ClOO + Cl

  • UV light breaks apart the dimer, releasing one Cl atom and one ClOO radical.

• ClOO → Cl + O₂

  • The ClOO radical breaks apart, releasing another Cl atom and oxygen gas.

what are the three equations related to light

1) speed of light m/s = (wavelength nm) (frequency 1/s)

2) energy J = (h-constant Jxs) (speed of light m/s) / wavelength m

3) energy J = (h-constant Jxs) (frequency 1/s)

equation for energy needed for each energy level for electrons to jump to

E = -R_H / n²

equation for number of absorption/emission lines

n (n-1) / 2

how do you calculate average bonds

# of indiv lines b/w indiv atoms / total # bonds in molecule

rate the three types of bonds in order of longest to shortest AND most energy to least energy

1) single (longest, least energy)

2) double

3) triple (shortest, most energy)

how many atoms are needed in order to find average bond order

more than two atoms

what are the rules for determining if bond is polar or non-polar

polar:

• polar bonds AND dipoles don’t cancel

non-polar:

• only non-polar bonds OR dipoles cancel

what are the three foundations of chemistry

1) macroscopic

2) particulate

3) symbolic