1. Kinetic energy is the energy of motion of particles in a substance. Temperature is related to average kinetic energy - higher temperature means higher average kinetic energy. An olympic pool of cool water would have lower kinetic energy than a cup of hot coffee.
2. Liquids and gases are fluids that can flow. In liquids, molecules are close together due to intermolecular forces, but can move past one another. Evaporation occurs when molecules at the surface escape, cooling the liquid. In a closed system, evaporated molecules form a vapor in equilibrium with the liquid.
3. Vapor pressure increases with temperature as molecules gain kinetic energy. The boiling point is reached when vapor pressure equals external pressure and
Both liquids and gases can flow. The liquid on the left is colored water. The gas on the right is bromine vapor. If a gas is denser than air, it can be poured from one container into another. These pictures were taken in a fume hood because bromine is both toxic and corrosive. Predicting Over time, what will happen to the gas in the uncovered beaker? Explain .
The process of evaporation has a different outcome in an open system, such as a lake, than in a closed system, such as a terrarium. a) In an open container, molecules that evaporate can escape from the container. b) In a closed container, the molecules cannot escape. They collect as a vapor above the liquid. Some molecules condense back into a liquid.
The process of evaporation has a different outcome in an open system, such as a lake, than in a closed system, such as a terrarium. a) In an open container, molecules that evaporate can escape from the container. b) In a closed container, the molecules cannot escape. They collect as a vapor above the liquid. Some molecules condense back into a liquid.
On the graph, the intersection of a curve with the 101.3-kPa line indicates the boiling point of that substance at standard pressure. INTERPRETING GRAPHS a. Analyzing Data What is the boiling point of chloroform at 101.3 kPa? b. Analyzing Data What is the vapor pressure of ethanol at 40°C? c. Analyzing Data What would atmospheric pressure need to be for ethanoic acid to boil at 80°C?
A liquid boils when the vapor pressure of particles within the liquid equals the atmospheric pressure. The boiling point varies with altitude.
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