Chemistry 20.01-16 Flashcards
General chemistry multiple choice
1) Intermolecular forces between H2O and Na+ are
a) covalent bonds of σ and π
b) hydrogen bonds
c) dipole - ion interactions
d) dipole - dipole interactions
e) dipole – induced interactions
c) dipole - ion interactions
2) What is the only correct statement about electrical dipole moment
a) attraction force between ions
b) CO2 molecules has non-zero dipole moment
c) It is a vector (Q*D) where D is distance of Q
d) It is the time where a polar compound in the reaction
e) H2O molecule has zero dipole moment
c) It is a vector (Q*D) where D is distance of Q
3) The maximum # of electrons in the 4d (1=2) subshell is
a) 2
b) 4
c) 6
d) 8
e) 10
e) 10
4) Hybridization state of carbon in ethane
a) Sp3
b) Sp2
c) Sp
d) Sp3d
e) Sp3d2
a) Sp3
5) Lewis acids are
a) Neutron donors
b) Electron acceptors
c) Proton acceptors
d) Electron pair acceptors
e) Electron pair donors
d) Electron pair acceptors
6) A=PH:7 B=PH:14 this mean that the concentration of OH- ions is
a) 2 times higher in A than in B
b) 2 times higher in B than in A
c) 10^7 times higher in A than in B
d) 10^7 times higher in B than in A
e) Same in both
d) 10^7 times higher in B than in A
Brief questions general chemistry
1. Define the law of mass action
aA+bB↔cC+dD
Brief questions general chemistry
2. Write the half-life of a second order reaction
2A –> products or A + B –> products (when [A] = [B]), rate = k[A]2:
t½ = 1 / k [Ao]
Brief questions general chemistry
3. What is the conjugated acid and base of HCO3- anion
Acid: H2CO3
Base: CO32-
Brief questions general chemistry
4. Define the electronegativity of an atom, how is it changing in a given group (column) of elements.
Electronegativity is a measure of the tendency of an atom to attract a bonding electron pair.
Brief questions general chemistry
5. Write the ionic product, Kw, of water. (equation)
Kw is essentially just an equilibrium constant for the reactions shown. You may meet it in two forms:
Based on the fully written equilibrium:
* KW=(H3O+)(OH-)
Simplified equilibrium:
* KW=(H+)(OH-)
Brief questions general chemistry
6. Give an example of a weak acid-base and strong acid-base
- Strong acid: HCl
- Weak acid: CH3OOH
- Strong base: NaOH
- Weak base: NH3
Brief questions general chemistry
7. Define the Le Chatelier-Braun principal
Whenever a system in equilibrium is disturbed the system will adjust itself in such a way that the effect of the change will be nullified
Brief questions general chemistry
8. What is a buffer? Give an example
A buffer is an aqueous solution consisting of a weak acid and its conjugate base (basic buffer), or vice versa (acidic buffer).
Its pH changes very little when a small to moderate amount of a strong acid or base is added and therefore a buffer is used to prevent changes in the pH of a solution.
Acidic: A solution containing an acetic acid, CH3-COOH and sodium acetate I.e. CH3-COONa.
Basic: A solution containing ammonium hydroxide i.e. NH4OH and ammonium chloride I.e. NH4Cl.
Brief questions general chemistry
9. Give an example (name) of an intensive parameter. (ie: physical quantity)
An extensive property is a property that changes when the size of the sample changes. Examples are mass, volume, length, and total charge.
An intensive property doesn’t change when you take away some of the sample. Examples are temperature, colour, hardness, melting point, boiling point, pressure, molecular weight, and density.
