test 1 – Chemistry Flashcard

Intramolecular forces
Attractions between atoms
Types of Intramolecular forces
Ionic – positive and negative ions that form a lattice

Covalent – sharing of electrons between atoms

Metallic – electrons shared between closely packed ions

Intermolecular forces
Attraction between molecules

(Coloumbs law)F= (Q1 x Q2)/r2

(Size increase, strength increases)

What are Cohesive and Adhesive forces?
Cohesive- between similar molecules

Adhesive- between two different molecules

ex: Cl2-Cl2 cohesive

What are dipole-dipole forces and between which molecules do they occur?
Attraction between positive and negative ends of molecules. only occurs between polar molecules

Gets stronger as dipoles gets bigger

What is Hydrogen bonding and what elements are needed for it to occur?
A strong electronegative element is attracted to a hydrogen connected to another electronegative element on a 2nd molecule.

(F, O, N)=x

x—-h-x

What are dispersion forces?

What determines the dispersion forces between molecules?

Dispersion forces are temporary dipoles.

occurs in polar and non-polar molecules

larger molecules have larger dispersion forces

Ion-Dipole forces
Attraction between Ion and partial charges on a polar molecule.

Dipole-Induced Dipole
When a polar molecule induces a dipole in another molecule

Strengths of Intramolecular and Intermolecular bonds
Ionic bonds- 600-8000 KJ/mol (Lattice)

Covalent bonds- 100-1100 KJ/mol (bond association)

Intermolecular

ion-ion – 250KJ

Hydrogen bonding – 20KJ

Other forces are small

Inter less then Intra

What forces are broken in Chemical and Physical Changes?
Chemical- Intramolecular forces are broken

Physical- Intermolecular forces are broken

Intermolecular forces intact

Adding heat to a sample increases _______ or ___________.
Kinetic energy- increases temp. uses

q=mc(change in)T

Potential Energy- no change in temp.

occurs at melting and boiling points

energy goes into breaking intermolecular forces

uses (change in)H

Ionic compounds have ______melting points, usually _______celcius
high

thousands of degrees

What is the general range of melting points for covalent bonds?
in the low hundred degrees celcius.
What is an example of Covalent network bonds?
Carbon, graphite or diamond form.

Covalent bonds are prevalant instead of intermolecular bonds. makes melting and boiling points higher.

Which has a higher boiling point:

H2S (MW=34) or N2 (MW= 28)

H2S is higher because it is polar. (-60 degrees celcius)

N2 (-196 degrees celcius)

1 atm = ____kPA = ___ mm Hg = ___ torr= ____psi
1 atm = 101kPA = 760 mmHg = 760 torr = 14.7 psi
Properties of an Ideal Gas
Zero volume

behave independently of each other (no attraction or repelling)

Ideal at low pressure, high temperature

What is avogardo’s law?

Is it a direct or indirect realtionship?

As moles of gas increases, volume increases. Direct relationship.
What is Boyle’s law?

Direct or indirect realtionship?

As pressure increases, volume decreases. Same vice versa.
Indirect relationship.
What is the ideal gas law?
PV=nRT

P=pressure

V=Volume

n= moles

R= (0.0821)

T= Temperature

What is Charle’s law?

direct or indirect?

As Temperature increases, volume increases. Direct relationship.
What is the Combined Gas Law?
(P1V1)/T1= (P2V2)/T2

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