chemistry bonding part 3 default

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  • Created by: I.m
  • Created on: 05-12-12 22:32
For a molecule to have permanent dipole-dipole forces was must it be?
To have permanent dipole-dipole forces the molecule must be polar.
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What is hydrogen bonding?
Hydrogen bonding is a special, strong type of permanent dipole-dipole interaction.
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In which molecules can hydrogen bonding be found?
Hydrogen bonding is found in molecules containing O-H and N-H groups (e.g. H₂O and NH₃).
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Draw the diagram to show hydrogen bonding between ammonia molecules and water molecules.
Check in booklet for answers.
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Give in order from highest to lowest of strength of the 5 intermolecular forces.
1.) Ionic and covalent bond 2.) hydrogen bond 3.) dipole-dipole attraction 4.) Van der Waals’ forces.
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Why is ice unusual?
Ice is unusual because it is less dense than liquid water.
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Does water have a high or low melting/boiling point?
Water has a relatively high melting and boiling point.
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Why does water have a high melting/boiling point?
Hydrogen bonds are extra forces on top of Van der Waals’ forces. When ice is melted or water is boiled, these strong H-bonds need to be broken. More energy is needed to do this than for other molecules which do not possess hydrogen bonding.
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What does the physical properties of a material (e.g. melting point, electrical conductivity etc.) depend on?
The physical properties of a material depend on its structure and bonding.
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What are lattices/crystals?
Materials that have regular arrangements of particles are known as lattices or crystals.
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What are the four main types of lattices?
Giant ionic, giant metallic, simple molecular lattices and giant covalent lattices.
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What do all ionic compounds exist as in the solid state?
In the solid state, all ionic compounds exist as giant ionic lattices.
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Why do giant ionic compounds have high melting/boiling points? Explain your answer
The strong electrostatic attraction between oppositely charged ions is very strong so they require more energy to break therefore giant ionic compounds have high melting/boiling points.
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Do giant ionic compounds conduct electricity?
In the solid state, giant ionic compounds do not conduct electricity as the ions are fixed in place and cannot move. Giant ionic com pounds conduct electricity when molten state or aqueous solution. This is because the ions are free to move.
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Are giant ionic compounds soluble?
onic compounds are soluble in polar solvents such as water. This is because the polar water molecules can break up the lattice and surround the ions to form a solution.
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Are giant ionic compounds hard?
Giant ionic compounds are hard because there is a hard, strong electrostatic force of attraction (ionic bonding) that holds the ions together between ions. *ions arranged in layers and break the layers apart.
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Are giant ionic compounds brittle?
Ionic cyrstals are brittle. If hit hard enough, one layer is forced over the one next to it. This causes repulsion between the layers, splittling the cyrstals.
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What two structures can covalent compounds exist as?
Covalent compounds can exist as either simple molecular lattices or giant covalent lattices.
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What are simple molecular lattices made up of?
They are made up of small simple molecules e.g. H₂, O₂, N₂, CO₂, CH₄.
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Explain how the bonds are held together in a solid simple molecular lattice?
In a solid simple molecular lattice e.g. iodine I₂ within each I₂ molecule the iodine atoms are held together by strong covalent bonds. The I₂ molecules are held together by weak intermolecular forces.
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Do simple molecular lattices have high or low melting/boiling points?
Simple molecular lattices have low melting/boiling points because molecules are held together by weak forces between molecules.
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Do simple molecular lattices conduct electricity?
No because there are no free charged particles.
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Are simple molecular lattices soluble in water?
Simple molecular lattices are soluble in non-polar solvents because Van der Waals’ forces form between the simple molecular structure and the non-polar solvent.
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What are giant covalent lattices also known as?
These are also known as macromolecules.
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What are the three common types of giant covalent lattices?
The two common types of these structures are the 2 allotropes of carbon = diamond and graphite. They both consist of covalently bonded C atoms. Silicon dioxide SiO₂ also has a giant covalent structure.
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What are allotropes?
Allotropes are different forms of the same atom.
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What is the shape of a giant covalent structure?
Unlike small molecules the covalent bonding in these giant molecules extends throughout a giant three-dimensional structure.
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Describe the structure/bonds of diamond?
Strong covalent bonds through giant structure. Each carbon atom makes 4 strong covalent bonds to neighbouring atom.
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Describe the structure/bonds of graphite?
Strong covalent bonds within layers. Weak Van der Waals’ forces between layers. Each carbon atom makes 3 covalent bonds to neighbouring atoms.
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What is the third allotrope of carbon?
Buckminster fullerene.
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Do giant covalent (molecular) lattices have high or low melting/boiling points?
High temp needed to break strong covalent bonds in lattice.
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Do giant covalent (molecular) lattices conduct electricity?
Explain your answer. They do not except for graphite because there are no free charged particles except in graphite.
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Are giant covalent (molecular) lattices soluble? Explain your answer.
They are insoluble because they are giant structures with very strong bonds.
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Can diamond conduct electricity?
No because there are no delocalised electrons.
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Can graphite conduct electricity?
Yes because the spare electron from each carbon atom is delocalised. Each carbon atom only makes 3 bonds so has a spare electron. The electrons become delocalised and carry current.
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Describe the hardness of diamond?
It is very hard (one of the hardest materials you can get) because it has 4 strong covalent bonds to neighbouring atoms.
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Describe the hardness of graphite?
It is soft.
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What happens to atoms in metallic bonding?
In metallic bonding, atoms are ionised.
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What do the positive metal ions occupy in the giant lattice structure?
The positive metal ions occupy fixed positions in the giant lattice structure.
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What happens to the outer shell electrons in metallic bonding?
The outer shell electrons are delocalised i.e. shared between all the atoms in the structure
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What is the giant lattice structure held together by?
The giant lattice structure is held together by metallic bonding.
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What is metallic bonding?
Metallic bonding is the electrostatic attraction between positive metal ions and delocalised electrons.
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Do metals have high or low melting/boiling points?
Metals have high melting/boiling points because there is a strong electrostatic attraction between the positive metal ions and delocalised electrons.
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Can metals conduct electricity?
Yes because they have delocalised electrons that carry current and cam move freely through the lattice.
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Are metals malleable (can be shaped) and ductile (can be stretched)?
s because the positive metal ions can slide over each other when force is applied.
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Do hydrogen bonded atoms have high or low melting/boiling points?
They have a medium melting/boiling point because of the strong forces between the Hs+ on one molecule and a lone pair of electrons on an Os-
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Can hydrogen bonded atoms conduct electricity?
No because there are no free charged particles.
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Are hydrogen bonded atoms soluble?
Soluble in polar solvents as they can form hydrogen bonds.
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Other cards in this set

Card 2

Front

What is hydrogen bonding?

Back

Hydrogen bonding is a special, strong type of permanent dipole-dipole interaction.

Card 3

Front

In which molecules can hydrogen bonding be found?

Back

Preview of the front of card 3

Card 4

Front

Draw the diagram to show hydrogen bonding between ammonia molecules and water molecules.

Back

Preview of the front of card 4

Card 5

Front

Give in order from highest to lowest of strength of the 5 intermolecular forces.

Back

Preview of the front of card 5
View more cards

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