Question

Open the PhET States of Matter Simulation to answer the following questions:

(a) Select the Solid, Liquid, Gas tab. Explore by selecting different substances, heating and cooling the systems, and changing the state. What similarities do you notice between the four substances for each phase (solid, liquid, gas)? What differences do you notice?

(b) For each substance, select each of the states and record the given temperatures. How do the given temperatures for each state correlate with the strengths of their intermolecular attractions? Explain.

(c) Select the Interaction Potential tab, and use the default neon atoms. Move the Ne atom on the right and observe how the potential energy changes. Select the Total Force button, and move the Ne atom as before. When is the total force on each atom attractive and large enough to matter? Then select the Component Forces button, and move the Ne atom. When do the attractive (van der Waals) and repulsive (electron overlap) forces balance? How does this relate to the potential energy versus the distance between atoms graph? Explain.

Answer 1

The PhET simulation demonstrates phase changes and intermolecular forces through interactive experimentation with solids, liquids, and gases. It provides visual insights into temperature's correlation with the strength of intermolecular attractions and the balancing of forces at stable configurations.

Step-by-step explanation:

The PhET States of Matter Simulation allows students to explore how different substances behave in various phases: solid, liquid, and gas. When comparing the four substances in the PhET simulation, you may notice that solids have their particles in a fixed, closely packed arrangement, while liquids have particles that are close but can move around, and gases have widely spaced particles that move freely. The differences among substances in the same phase are often subtler but can include variations in particle spacing and motion intensity due to intermolecular forces.

In the simulation, substances demonstrate distinct temperatures at which phase changes occur, revealing the relative strengths of their intermolecular attractions. Stronger intermolecular forces result in higher temperatures needed for melting and boiling, as more energy is required to overcome these attractions. In the Interaction Potential tab, the total force on a neon atom is attractive and significant when atoms are at an optimal distance—neither too close nor too far apart. The attractive and repulsive forces balance at a specific distance where the potential energy graph shows a minimum, indicating stable configurations of atoms or molecules in a substance.