IB HL Intermolecular Forces | Baamboozle - Baamboozle

What is the bond order of NO3-?

1.3

1.5

3

1

Which of the following has the shortest bond

triple

single

double

quadruple

If a molecule has 4 bonds and one lone pair, what is its shape?

see-saw

T-shaped

trigonal bipyramidal

square pyramidal

Which would have the highest Rf?

non-polar molecule

very polar

intermediate polarity

slightly non-polar

What is ethyl acetate?

A solvent of medium polarity

State the relationship between IMF and vapor pressure

A liquid with weak intermolecular forces evaporates more easily and has a high vapor pressure.

Give the two common materials used in TLC as the stationary phase

Alumina (Al2O3) and Silica (SiO2)

What does "HPLC" stand for?

High Performance Liquid Chromatography

In paper chromatography, why do we use pencil instead of pen in writing the starting line?

pencil = insoluble in solvent; pen = soluble; may interfere with the results

Explain why CO is polar while CO2 is nonpolar.

O is more EN than C; CO has uneven distribution of e in bond, thus polar; CO2 is linear (symmetrical), charge distribution is even, thus non-polar

Explain why polar molecules are often soluble in water while non-polar molecules are not. Include discussion on the intermolecular processes involved in dissolving.

soluble = IMF solute and IMF solvent are similar; water is polar = h-bonding and dipole dipole; nonpolar solute = dispersion (way weaker than IMF in solvent)

Explain the following trend in boiling points: CH4 < C2H6 < C3H8

All molecules are nonpolar = only dispersion forces = increase in mass = stronger dispersion forces = higher BP

What element combines with another element by sharing 1 pair of valence e and combines with hydrogen to form a molecule that exhibits hydrogen bonding?

Fluorine

Give an example of a substance that has a very high 1st ionization energy, a very low BP and does not form bonds.

(answers may vary - any noble gas)

Give an example of a substance that is very soluble in water and has a pyramidal shape.

(answers may vary - NH3, PH3, ...)

State the electron domain, molecular shape, bond angle/s and polarity: CH2O

3, trigonal planar, 120, polar

State the electron domain, molecular shape, bond angle/s and polarity: [CO3]2-

3, trigonal planar, 120, non-polar

State the electron domain, molecular shape, bond angle/s and polarity: [NH4]+

4, tetrahedral, 109.5, non-polar

State the electron domain, molecular shape, bond angle/s and polarity: HCN

2, linear, 180, polar

State the electron domain, molecular shape, bond angle/s and polarity: SO2

3, bent, 117.5, polar

State the electron domain, molecular shape, bond angle/s and polarity: SO3

3, trigonal planar, 120, non-polar

State the electron domain, molecular shape, bond angle/s and polarity: BeI2

2, linear, 180, non-polar

State the electron domain, molecular shape, bond angle/s and polarity: BF3

3, trigonal planar, 120, non-polar

State the electron domain, molecular shape, bond angle/s and polarity: PH3

4, trigonal pyramidal, 107, polar

State the electron domain, molecular shape, bond angle/s and polarity: H2S

4, bent, 104.5, polar

State the electron domain, molecular shape, bond angle/s and polarity: CH4

4, tetrahedral, 109.5, non-polar

Explain why pure carbon has a melting point of approximately 3550C while pure nitrogen has a melting point of -210C.

Carbon = giant covalent structure = strong bonding; N2 molecule = weak dispersion forces between particles = requires lesser energy to separate them

Why is the melting point of HI higher than HBr?

HI has greater molar mass (more electrons) and so it has stronger dispersion forces than HBr

Explain why the melting point of HF does not follow the trend of the other hydrogen halides.

HF has hydrogen bonding as its main IMF; while HCl, HBr, HI have dipole-dipole which is a generally weaker IMF than Hydrogen bonding

Explain why HCl is more soluble in water than Cl2.

HCl is a polar molecule (forms ion-dipole interaction with water) while Cl2 is non polar