Karteikarten
Chemistry Module 2: Chapter 6.3
Karten in diesem Stapel (14)
- 1What are induced dipole-dipole interactions (AKA London forces)? What are permanent dipole-dipole interactions?-They are weak IMF's which exist between all molecules polar and non-polar.
- 2how do induced dipole-dipole interactions (AKA London forces) work?-Electrons in the electron cloud are constantly moving. This means that at moments the electrons will be closer to one atom than another forming a temporary dipole. This temporary dipole induces another temporary dipole on the neighbouring molecules which induce the next attracting them all to eachother. Because electrons are continuously moving the dipoles are constantly being made and destroyed.
- 3How do electrons affect the strength of induced dipole-dipoles.1) This is because there are more electrons moving so there are longer instantaneous and induced dipoles.
2) More electrons mean greater induced dipole dipole interactions (more atoms are induced)
3) More electrons means stronger attractive forces between molecules
4) More electrons means larger induced dipoles
5) Large ammounts of IMF incraese the boiling/melting point so more energy is needed to overcome them. - 4What are Van der Waals forces? What are london forces?-Van der Waals forces are both induced dipole-dipole interactions, as well as permenant dipole-dipole interactions
-London forces are only induced dipole-dipole interactions - 5How do permanent dipole-dipole interactions work?-Dipolar molecules which have permanent dipoles attract opposing dipoles, the attraction between the two is a permanent dipole dipole interaction as it is not induced or temporary.
- 6Explain the polarity of a F --- F bond? Explain the polarity of a H --- Cl bond? Why does H---Cl bonds have a higher boiling point than F---F bonds?-F --- F bonds are non polar as they have the same electronegativity, this means they dont have van der waal forces, however because electrons are constantly moving they have london forces
-H --- Cl bonds are polar as the Cl has a higher electronegativity than hydrogen. This causes Cl to pull the electrons closer to it forming a slightly negative dipole. Because of this we can say H---Cl bonds have van der waal forces
-This is because H---Cl bonds have van der waal forces and F---F only have london this means HCL has stronger and more intermolecule forces acting upon it so its boiling point is higher. This means more energy is required to break these bonds hence why its boiling point is higher - 7What is a simple molecular lattice? How are the molecules and the simple lattice held together?-A simple molecular lattice is a lattice made from simple molecules in a solid state
-The atoms in the molecules are bonded by strong covalent bond, and these molecules are then held together by the weak intermolecular forces (IMF) - 8What are properties of simple molecular substances?-All are covalently bonded.
-Can be solid/liquids/gases
-They can all be used to make simple molecular lattices as long as they are in solid states
-They have low boiling and melting points
-Low ammounts of energy are needed to overcome the weak IMF - 9What happens when a simple molecular lattice is broken down during melting?-When a simple molecular lattice is broken down enough energy has been supplied to break the weak IMF. This causes the the lattice to be broken down. The covalent bonding between the atoms are strong this means they are not overcome by the energy supplied during melting
- 10What happens when a non polar simple molecular compound is added to: -A non polar solvent -A polar solvent-When added to a non polar solvent intermolecular forces form between the molecules and the solvent and the simple molecules dissolve into the solvent. This is because it weakens the IMF in the simple compound.
-When added to a polar solvent very little happens, this is because IMF in the polar solvent are too strong to be broken hence the simple molecular compound doesnt dissolve. - 11Explain what happens when iodine is dissolved in: Water Cyclohexane
- 12Why do polar simple molecular compounds only dissolve in some polar solvents? What happens when a polar simple molecular compound is added to a non polar solvent? Why is it hard to predict the soluability of 2 polar chemicals?-This is because they will only dissolve if the solvent and solute molecules attract each other meaning they would need to have strong enough dipoles, the stronger the dipoles the more soluable it is.
-The IMF between the solute and solvent will form and the solute will dissolve.
-This is because the soluability is dependant on the strength of the dipoles, and it is hard to predict dipole strengths - 13Why are simple molecular compounds non-conductors of electricity?-This is because all the molecules are held together by the IMF meaning there are no mobile charged particles. And because none of the atoms/particles are mobile electricity cannot be conducted.
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- A level Chemistry (Generals) Karteikarten am Chemistry Module 2: Chapter 6.3, erstellt von BUKDABOSS . am 05/03/2019.
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