Forces between atoms

Definition: Work is defined as the force multiplied by the distance moved in the direction of the force, represented mathematically as W = F · d.
Unit of Work: The standard unit of work is the Joule (1J). Notably, 1J is equivalent to 1 Newton meter (1N · 1m).
Energy Concept: Energy can be understood as the ability to perform work and can be conceptualized as stored work.

Scenario: Consider moving a mass m from the floor to a 2m high shelf.
- Height (h) increases when lifting (h = 0 to h).
- The force of gravity acts downward, which is negative and opposite the direction of height (+h).
- The force required to lift the mass must match or exceed the gravitational force (positive direction along +h).
Calculation: Work done in this scenario can be defined as W = F · d, leading to W = mgh.
- This indicates that the work done to lift the mass is stored as potential energy in the mass/shelf system once positioned on the shelf.

Definition: Potential energy (PE) represents the energy an object possesses due to its position within a force field (e.g., gravitational field).
Example Context: The potential energy of the mass lifted onto the shelf is equal to the work done against gravity, thus becoming mgh.

Energy Change: When the mass falls from the shelf, its potential energy (PE) transforms into kinetic energy (KE).
Process: As the mass falls:
- Height decreases while gravity acts (h increases as it falls).
- Work is calculated using W = F · d, therefore relating to mass acceleration due to gravity.
Relation: Kinetic energy can be defined and calculated using the formula W = mv²/2.
Definition of K.E.: Kinetic energy is the energy an object has due to its motion. The K.E. gained when the mass falls equals the potential energy it possessed on the shelf, now maximal just before impact with the ground.

Energy Loss: A mass falling a distance of –h loses potential energy quantified as –mgh, considering h reaches zero and then negative.
Well Shape: Regardless of the well's shape, potential energy decreases as the mass travels to a lower potential energy state.

General Principle: Systems naturally progress towards a state of lower potential energy.
Thermodynamics Insight: The loss of potential energy typically converts into heat, embodying the Second Law of Thermodynamics, where a system reaches a maximum entropy (disorder) at equilibrium.

Model: The composition of an atom includes electrons orbiting a nucleus. Visual representation demonstrates the scale, with electrons found in specific paths at distances of the order of 10^-10 m to 10^-14 m.

Composition: Represents a water molecule, consisting of two hydrogen atoms and one oxygen atom (H2O). The model visually depicts molecular structure.

Attributes: Attractive forces have a negative sign (against measurement of distance), while repulsive forces are positive (in the same direction).
Nature: Forces between molecules are fundamentally electrostatic; opposites attract, and like charges repel, giving rise to the formula F = (1/4πε0) · (Q1Q2/r²), where Q1 and Q2 are charges and r is the distance between them.

Equation: The net force (F/N) between molecules equals zero at a specific distance (ro), indicating equilibrium between attractive and repulsive forces under varying separation distances.

Potential Energy: Potential energy (Ep) approaches zero in gaseous phases when molecules are significantly apart, influencing their interactions such as binding energy in liquids and solids.

Phases: Molecular characteristics vary across solid, liquid, and gas phases, with solids having fixed positions, liquids exhibiting slight movement, and gases demonstrating high energy and movement variability.

Models: Schematic representations illustrate the behavior of particles across solid, liquid, and gas phases, providing insight into their arrangement and motion.