Uncertainty in Measurement & precision/accuracy

This section in the textbook talks about the difference between measurements that have good precision versus those that have good accuracy or those that have neither or both.

Classification of Matter
Physical & Chemical Properties
Physical & Chemical Changes

This section in the textbook talks about the how to determine if a sample is a mixture, solution, compound, or element.   It also talks about what are physical properties and chemical properties, plus how to recognize a physical change versus a chemical change.

In the picture, the man is using a sluice to separate gold from a mixture of sand and water.  That involves knowing the physical properties of sand and gold and doing physical changes to extract the gold.