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CH 101 A Molecular Science (Exam Review)
NCSU course
59
Chemistry
Undergraduate 1
12/09/2011

Additional Chemistry Flashcards

 


 

Cards

Term

When two like charges interact, which combo gives it the highest energy?

 

small/large charge & close/far

Definition

 

Large charges close together

Term
When two particles move through a magnetic field, and one particle is refracted twice as far as the other, what two differences between the particles is possible?
Definition
One may be twice the charge or twice the mass (this one will refract twice as much).
Term
Which subatomic particles are responsible for the mass of an atom?
Definition
Protons and neutrons
Term

What transition combo is the absorption process that requires the most energy?

From a higher/lower n to a higher/lower n in a higher/lower level of n.

Definition

From a lower n value to a higher n in a lower level of n.

 

Ex: n=1 → n=3

Term
How would you describe the location cloumn of K on the periodic table?
Definition
It is an alkali metal.
Term
If element A has valence electrons at a higher level then B, then which has the higher ionization energy?
Definition
Because A has a higher valence electon level, it has the higher ionization energy.
Term
Which corner of the periodic table has the highest electronegativity?
Definition

 

Top-right corner.

Term
How would you find elements whose highest occupied orbital is the 4p orbital when in ground state?
Definition
Find the p-block (rightmost block) and count down four rows. All the elements in this row and block have the highest occupied orbital of 4p.
Term
How do you know an ionic compound from another compound?
Definition
An ionic compound will be made of a metal and non-metal.
Term
What orbital letters can hold how many pairs of electrons?
Definition

s: 1 pairs

p: 3 pairs

d: 5 pairs

Term
How do you figure out what the greatest mass is amongst elements given in moles, number of atoms, and mass?
Definition

Convert the number of atoms into moles (divide by 6.02×1023)

Convert the moles into grams (multiply by the elements' molar masses)

Term
How do you compare the number of atoms in samples of atoms in grams, moles, and number of atoms.
Definition

You can easily convert them to moles.

To convert grams to moles, divide by the elements' molar masses.

To convert number of atoms to moles divide by 6.02×1023.

Term
What corner of the periodic table has atoms with the largest radius and what charge increases atomic radii?
Definition
Bottom-left corner. A negative charge increses the size of the radius.
Term
How can you tell if a bond has more ionic character or covalent character?
Definition
The greater the difference in electronegativity between the two atoms, the more ionic the character. The closer the electronegativities, the more covalent the character.
Term
The n=1 level is higher for atoms in what corner of the periodic table?
Definition
Top-right corner
Term
When n=1 is high and a transition is made from n=2 → n=1, will the photon from that trasition be at high or low energy?
Definition
It will be at low energy.
Term
How do you find the number of valence electrons in a element's atom?
Definition
Count on that elements row from left to right. The number of elements you counted is the number of valence electrons.
Term
To find the number of atoms in a compound, what to you do?
Definition
Take the number of "ingredients" (like 2 hydrogen and 1 oxygen for H2O) and multiply it by the number of moles. Then you can convert moles to number of atoms (6.02×1023)
Term
If a atom is in a bond and has two attachments (either single, double, or triple bonds or lone pairs) what is it's bond angle?
Definition

 

180°

Term
If an atom is bonded and has three parts (either single, double, or triple bonds or lone pairs), what is the bond angle?
Definition

 

120°

Term
If an atom is bonded and has four parts (either single, double, or triple bonds or lone pairs), what is the bond angle?
Definition

 

109°

Term
If an atom is bonded and has two parts (either single, double, or triple bonds or lone pairs), what is the hybridization?
Definition

 

sp

Term
If an atom is bonded and has three parts (either single, double, or triple bonds or lone pairs), what is the hybridization?
Definition

 

sp2

Term
If an atom is bonded and has four parts (either single, double, or triple bonds or lone pairs), what is the hybridization?
Definition

 

sp3

Term
What are the number of sigma and pi bonds in single, double, and triple bonds?
Definition

single: 1σ   

double: 1σ 1π

triple: 1σ 2π

Term
How can a bond order can be found?
Definition
Take the average of all possible bonds.
Term
In sigma bonding, where is the electron density concentrated?
Definition
The most density is concentrated between the two nuclei.
Term
In pi bonding, where is the electron density concentrated?
Definition
It is concentrated above/below the two nuclei.
Term
Antibonding diagrams are shown how?
Definition
With two similarly colored orbitals overlapping each other.
Term
How does hydrogen bonding arise?
Definition
Hydrogen bonding forces arise from the interaction of a hydrogen atom with a lone pair on a neighboring molecule.
Term
Molecules with the highest boiling point have what kind of bonding?
Definition

1: Hydrogen bonding 

2: Dipolar bonding  

3: Dispersion forces

(weight is also a factor)

Term
The simple cubic cell has what coodination number and packing efficiency compared to the other cubic cells?
Definition
Simple cubic has the smallest coordination number and the worst packing efficiency.
Term
The body centered cubic cell has what coodination number and packing efficiency compared to the other cubic cells?
Definition
Body centered cubic cells have the middle coordination number and the medium packing efficiency.
Term
The face centered cubic cell has what coodination number and packing efficiency compared to the other cubic cells?
Definition
The face centered cubic cell has the largest coordination number and the greatest packing efficiency.
Term
What is the simple cubic cell's coordination number?
Definition
1
Term
What is the body centered cell's coordination number?
Definition
2
Term
What is the face centered cubic cell's coordination number?
Definition
4
Term
The less conductive a material, the larger or smaller the bandgap?
Definition
The bandgap is larger in materials that do not conduct well.
Term
Molecular solids tend to have what kind of boiling points?
Definition
Molecular solids have relatively low, normal boiling points.
Term
What is ΔH?
Definition
It is the change in enthalpy. Enthalpy is the sum of kinetic and potential energy.
Term
What is ΔS?
Definition
It is the change in entropy. Entropy is the number of ways molecules can be arranged in a system.
Term
If a weak bond is broken and a strong bond is formed, what is the most likely tempurature exchange?
Definition
Exothermic
Term
If a strong bond is broken and a weak one forms, what is most likely tempurature exchange?
Definition
Endothermic
Term
What is the equation for finding ΔH from bond energies?
Definition

ΔH

∑(broken bond energies)

-

∑(formed bond energies)

Term
If ΔH is positive, what was the heat transfer?
Definition
Endothermic
Term
If ΔH is negative, what was the heat transfer?
Definition
Exothermic
Term

What is the equation for the Second Law of Thermodynamics concerning free energy?

(Used to calculate spontaneity)

Definition

 

ΔG = ΔH - T×ΔS

If ΔG is negative, the reaction is spontaneous (and vice-versa).

Term
What is the difference between ΔG and ΔG°?
Definition
ΔG° is for specific amounts of reactant and product, ΔG is for unspecified amounts.
Term
If a reversible reaction's ΔG° is negative, then what is K in relation to 1 at equilibrium?
Definition
K > 1
Term
If a reversible reaction's K value is greater than 1, then what is true about the activation energy at equilibrium?
Definition
The activation energy of the foreward reaction is less than that of the reverse reaction.
Term
When you increase tempurature, what happens to the number of collisions in a system?
Definition
It increases.
Term
How does a catalyst help a reaction?
Definition
It orients molecules porperly to speed up a reaction.
Term
If you decrease the concentration of reactants, what will happen to the speed of the reaction?
Definition
It will be slowed.
Term
If a reaction has a high activation energy, then what can you conclude about the reaction rate?
Definition
It has a very low reaction rate.
Term
How do detergents work?
Definition
They form a micelle with hydrocarbon tails pointing inwards.
Term
What is Avagadro's Number?
Definition
6.02 × 1023
Term
What is Coulomb's Law concerning force?
Definition
F ≈ (q1q2)/r2
Term
What is Coulomb's Law concerning energy?
Definition
E ≈ (q1q2)/r
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