Each learning path is one chapter: a guided route through a topic, one small course at a time. Pick a class to see its chapters in order.
How many molecules are in a sip of water? How much oxygen does a gas burner need? Chemistry answers such questions by counting particles in a clever way, with the mole. In this chapter you learn to measure carefully and to report a measurement honestly, meet the laws that led to the idea of atoms, and then use moles to find formulas, to work out the amounts in a reaction and to make solutions of a given strength. Python does the long arithmetic, so you can think about the chemistry.
Burn a candle, and the wax seems to disappear. Does matter really vanish in a chemical change? In this chapter we meet the two laws that scientists found by weighing before and after a reaction. They lead us to the atom, the tiny particle that every element is made of. We learn how atoms join to form molecules and ions, how to write a chemical formula, and how chemists count atoms with a unit called the mole. Python helps us with the calculations.