Temperature, States of Matter, and Gas Behavior
Think about why ice melts on a hot day. Temperature measures the average kinetic energy of particles, while heat is energy transferred between substances. All thermometers have two fixed points: water's freezing and boiling points, with 100 degrees between them.
Avogadro's Law tells us that gases at the same temperature, pressure, and volume contain equal numbers of molecules (but not necessarily atoms). This law connects directly to the mole concept, where one mole contains 6.02 × 10²³ particles.
Different states of matter behave differently because of their particle arrangements. Solids have definite shape and strong attractions between particles. Some solids with weak attractions can sublime (change directly from solid to gas). This happens because of their vapor pressure – the pressure exerted by a substance in its gaseous state.
Fun Fact: When you're at a higher altitude, water boils at a lower temperature because atmospheric pressure is lower. That's why it takes longer to cook pasta in the mountains!
Dalton's Law states that the total pressure of a gas mixture equals the sum of partial pressures of each gas. We can find a gas's contribution to total pressure using mole fractions – the ratio of moles of that gas to total moles in the system.