Presentation on theme: "AP CHEMISTRY. Review SI system -know prefixes in blue on pg 10 Mass vs weight-an object’s mass reflects the amount of matter it contains. An object’s."— Presentation transcript:
SI system -know prefixes in blue on pg 10 Mass vs weight-an object’s mass reflects the amount of matter it contains. An object’s weight is the pull of gravity on that matter.
Uncertainty Measurements should include all certain digits plus the first uncertain digit. Ex. Reading thermometer, buret, balance, etc. (On digital devices, the last digit shown is uncertain) So what is the reading from this graduated cylinder? How many decimals are acceptable here? The reading should be 52.8 ml where the 8 is the estimated digit.
You should be able to use and read these pieces of equipment.
How Many Significant figures? 4.0023 4.00 0.04003 0.04 0.040
Sig. Figs in Calculations: A Review significant figures in calculations When multiplying or dividing, use the smallest total number of sig. figs. When adding and subtracting, use the smallest number of decimal places. Ex. 3.0×6.00 = 18 3.0 + 6.00 = 9.0 exact numbers-have infinite sig. figs.
This may look like a middle school review, but do you really understand it all? Make sure that you do! Classification of Matter
Physical, Chemical, and Ambiguous Changes In a physical change, the chemical formula does not change. All phase changes are physical changes. In a chemical change, one or more new substances are formed. Sometimes the determination as to whether a change is physical or chemical is not so simple and the change is termed “ambiguous”. An example could be an ionic compound dissolving in water. Weak chemical bonds form between the water molecules and the dissolved ions.
When a calcium ion dissolves in water, what type of change has occurred?
Separation of Mixtures -distillation -chromatography -filtration
Gravity Filtration Vacuum Filtration Types of Filtration used in AP Chemistry
Chromatography Chromatography is a procedure that separates a mixture into its component parts based on the components attraction for the mobile and stationary phases. The distance that the component travels is compared to the distance that the mobile (solvent) phase travels on the stationary phase. Types of chromatography: Paper Gas Thin-layer Liquid