- Compound: 2 or more elements that are chemically bonded
- Mixture: no chemical bond between multiple elements
- Mixture
- Homogenous and heterogenous
- Homo: Can not distinguish what has been mixed from one another Eg. Sulfuric acid
- Hetero: You can still observe the different components Eg. Gun powder
- Kinetic theory
- Movement and arrangement of particles
- Everything is made of particles which are constantly moving
- Solids
- Packed closely together. Fixed position with strong attraction forces
- Only vibrate, and can not be compressed, has a fixed volume and shape, can not flow
- Liquids
- Close together but not packed, some attraction, free to move, can slide past each other and
therefore can flow
- Can not be compressed and have no definite shape, take the shape of the container
- Gas
- Spaced far apart, move around very quickly and collide with each other
- Can be compressed because the particles are so far apart, have no fixed volume or shape
Sublimation: Dry ice and iodine
Deposition: frosting
- Evaporation can happen at any temperature
- Boiling only at a certain temperature
, Word equation vs chemical equation
- Word is consisted of words, chemical is consisting of symbols
- U have to balance chemical equation to ensure that arrangement is correct
- A reaction must first break down the reactants, and then it rearranges them
- 2H2 + O2 → 2H2O
- Balanced equation is just a ratio of all, therefore they are considered as moles, not single particle
Moles
- Mole is just a number
- Eg. pair, trio, dozen or mole
- Mole is 6.02 x 10^23, just a number
- Eg. 1 mol of carbon: 12.01g
- 1 mol of calcium: 40.08g
- Molar mass calculated by adding all the protons, neutrons and electrons mass together
- Molar masses found in data booklet. Molar masses= relative atomic masses(used for single element)
- Molar mass= relative molecular mass(only covalent molecule), relative formula mass
- 1 mol of a compound, u just add the relative atomic masses together CH4 (12.01+1.01(x4))
- NaCl (22.99 + 35.45)
- All mean the same thing!!! Do not get confused