Pure substances are substances containing only one type of particle
A saturated solution is a solution with as much dissolved solute as possible at a particular temperature. There must be some undissolvedsolute present
Diffusion is when particles move from an area of high concentration to one of low concentration until evenly spread
A whitering of ammonium chloride is seen in a sealed tube when hydrogen chloride gas and ammonia gas diffuse towards each other. The ring forms slightly closer to the hydrogenchloride side
Hydrogen chloride + ammonia —> ammonium chloride
HCl + NH3 —> NH4Cl
Gases diffuse more quickly than liquids because the particles have more energy and are less dense. The more dense the gas is, the slower it diffuses
if the surfacearea increases, the number of available particles increases leading to more successful collisions per second and an increase in rate of reaction
The reaction between marble chips and hydrochloric acid is used to show the affect of surface area on rate of reaction
Concentration is a measure of the number of solute particles in a particular volume of solution
Pressure is a measure of the number of gas particles in a particular volume of space
An increase in gaspressure leads to an increase in concentration
If the concentration increases, the number of availableparticles increases leading to a greater number of successful collisions per second and an increased rate of reaction
Activation energy is the energy needed to start a chemical reaction by breaking reactant bonds
If the temperature is increased, the particles have more kineticenergy and move around more so collide moreoften. Also, a greaterproportion of the particles collide with an energy inexcess of the activationenergy
A catalyst is a substance that speeds up a chemical reaction without being used up
a catalyst provides a surface whereupon reactants are held in position so that the orientation is correct for the bond breaking and forming
a catalyst provides an alternative reaction pathway of lower activation energy
sodium thiosulfate and hydrochloric acid react to form sulfur
78% of the air is nitrogen
21% of the air is oxygen
0.9% of the air is argon
0.03% of the air is carbon dioxide
Oxygen is extracted from the air by the fractional distillation of liquefied air
The percentage of oxygen in the air can be determined by measuring the volume of air removed when iron is allowed to rust in a closed environment
The percentage of oxygen in the air can be determined by passing air repeatedly over heater copper and measuring the change in air volume
you can make oxygen by rapidly decomposing Hydrogen Peroxide (H2O2) using the catalyst Manganese dioxide to form water and oxygen gas
Hydrogen peroxide —> water + oxygen
Water will turn anhydrous copper (II) sulfate from white to blue