1 Particles + Mixtures Flashcards
What is a solid?
Strong forces of attraction,
lattice arrangement.
Vibrate about fixed positions.
Do solids move/flow?
No they have fixed shape and volume.
What is a liquid?
Weaker forces of attraction (but still pretty strong)
Free to move around set point
Constant movement in random motion
Do liquids move/flow?
Definite volume not definite shapes - will flow at bottom of container.
What is a gas?
Very Weak forces No arrangement (particles far apart) Constantly moving in random motion.
Do gases move/flow?
No constant shape or volume- always fill container.
Liquid -> Gas
Evaporation
Solid -> Gas
Subliming
Solid -> Liquid
Melting
Liquid -> Solid
Freezing.
Gas -> Liquid
Condensation.
What can be done instead of evaporation?
Boiling.
What is diffusion?
Gradual movement of particles from places where there are lots, to places where there are few.
(Basically just particles spreading out)
What colour is bromine gas?
Orange/brown
Describe Bromine?
Strong smelling.
A student fills a glass jar with bromine gas (bottom of glass), and the other with air (top of glass). Separated with a glass plate. They then remove the plate.
What happens?
Bromine diffuses up.
A student fills a glass jar with bromine gas (bottom of glass), and the other with air (top of glass). Separated with a glass plate. They then remove the plate.
Why is this process slow?
Because the particles are colliding.
A student fills a glass jar with bromine gas (bottom of glass), and the other with air (top of glass). Separated with a glass plate. They then remove the plate.
Why is diffusion caused?
Because the particles are moving in random motion.
A student fills a glass jar with bromine gas (bottom of glass), and the other with air (top of glass). Separated with a glass plate. They then remove the plate.
How would you speed this up?
Vacuum - no collisions
Hotter - more energy.
A student fills a glass jar with bromine gas (bottom of glass), and the other with air (top of glass). Separated with a glass plate. They then remove the plate.
What is different about the bromine at the start than at the end?
Conc. of bromine is less at end. However is uniform.
Aqueous ammonia (NH3) and Hydrochloric acid are at either ends of the tube soaked in cotton wool. Ammonia gives off Ammonia gas, and Hydrochloric acid gives off Hydrogen Chloride gas.
What happens?
Both gases diffuse across and react to form Ammonium Chloride.
Aqueous ammonia (NH3) and Hydrochloric acid are at either ends of the tube soaked in cotton wool. Ammonia gives off Ammonia gas, and Hydrochloric acid gives off Hydrogen Chloride gas.
Where is Ammonium Chloride produced and why?
Nearest to Hydrochloric acid because the particles are heavier.
A student places Potassium VII at the bottom of a beaker with water and it slowly spreads.
Why does this happen?
Because the particles are moving in random motion.
A student places Potassium VII at the bottom of a beaker with water and it slowly spreads.
What would happen if you added more water?
The mixture will slowly spread and become less purple (dilute)
What is a solution?
A solute + solvent mixture (doesn’t separate)
What is a solute?
Substance being dissolved.
What is a solvent?
The liquid the substance is dissolving into.
What is a saturated solution?
A solution where no more can be dissolved into it.
What is solubility?
The amount of substance that can be dissolved into a solvent.
What happens when you increase the temperature of a substance in terms of solubility?
The solubility increases.
A student wants to find the solubility of ammonium chloride (affected by temperature) They add excess solute to 10cm3 of water in a boiling tube. Give a good stir, and place in a water bath. After 5 mins they check if all the solute has dissolved and check the temperature. They then weight an empty evaporating basin. and pour the solution into the basin, re-weigh with the contents. Gently removing water with Bunsen burner by evaporation. Re-weigh. Repeat and calculate.
Why does the student add excess?
To make sure enough has been dissolved as possible.
A student wants to find the solubility of ammonium chloride (affected by temperature) They add excess solute to 10cm3 of water in a boiling tube. Give a good stir, and place in a water bath. After 5 mins they check if all the solute has dissolved and check the temperature. They then weight an empty evaporating basin. and pour the solution into the basin, re-weigh with the contents. Gently removing water with Bunsen burner by evaporation. Re-weigh. Repeat and calculate.
Why do they evaporate the water?
Because it could effect results?
A student wants to find the solubility of ammonium chloride (affected by temperature) They add excess solute to 10cm3 of water in a boiling tube. Give a good stir, and place in a water bath. After 5 mins they check if all the solute has dissolved and check the temperature. They then weight an empty evaporating basin. and pour the solution into the basin, re-weigh with the contents. Gently removing water with Bunsen burner by evaporation. Re-weigh. Repeat and calculate.
Why might the weight decrease?
Because the ammonium chloride itself may have evaporated.
Equation of solubility:
Solubility = (Mass of solid / Mass of solvent removed) x100
What is an isotope?
Same protons + electrons different neutrons.
What is filtration?
A process used to separate an insoluble solid from a liquid.
What is chromatography?
A process to separate dyes.
Why do we have a lid in chromatography?
So solvent doesn’t evaporate.
Why is the line not at bottom of paper in chromatography?
Doesn’t immediately dissolve.
Why is the line pencil in chromatography?
Lead is insoluble.
How to calculate Rf value in chromatography?
Rf = distance of dye / distance of solvent.
(Skipped distillation - atomic structure etc because easy) check notes to make sure you understand.
Did you actually do it tho?
