Physical Science SmartPrep Grade 12 Review

Comprehensive practice flashcards covering Grade 12 Physical Science (Physics and Chemistry) based on the Science Clinic SmartPrep syllabus summaries.

Normal force ($F_N$)

The force or the component of a force which a surface exerts on an object with which it is in contact, and which is perpendicular to the surface.

Frictional force ($F_f$)

The force that opposes the motion of an object and which acts parallel to the surface.

Newton's first law of motion

A body will remain in its state of rest or motion at constant velocity unless a non-zero resultant/ net force acts on it.

Newton's second law of motion

When a resultant/net force acts on an object, the object will accelerate in the direction of the force at an acceleration directly proportional to the force and inversely proportional to the mass of the object.

Newton's third law of motion

When object A exerts a force on object B, object B SIMULTANEOUSLY exerts an oppositely directed force of equal magnitude on object A.

Newton's Law of Universal Gravitation

Each body in the universe attracts every other body with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.

Momentum

The product of an object's mass and its velocity.

Principle of conservation of linear momentum

The total linear momentum of an isolated system remains constant (is conserved).

Projectile

An object which has been given an initial velocity and then moves under the influence of the gravitational force only.

Work-energy theorem

The work done on an object by a net force is equal to the change in the object's kinetic energy ($W_{net} = \Delta K = K_f - K_i$).

Conservative force

A force for which the work done in moving an object between two points is independent of the path taken.

Doppler Effect

The change in frequency (or pitch) of the sound detected by a listener, because the sound source and the listener have different velocities relative to the medium of sound propagation.

Coulomb's law

The magnitude of the electrostatic force exerted by one point charge ($Q_1$) on another point charge ($Q_2$) is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance ($r$) between them.

Ohm's law

The potential difference across a conductor is directly proportional to the current in the conductor at constant temperature.

Emf ($\varepsilon$)

The maximum energy provided by a battery per unit charge passing through it.

Photoelectric effect

The process whereby electrons are ejected from a metal surface when light of suitable frequency is incident on that surface.

Threshold frequency ($f_0$)

The minimum frequency of light needed to emit electrons from a certain metal surface.

Work function ($W_0$)

The minimum energy that an electron in the metal needs to be emitted from the metal surface.

Functional group

A bond or an atom or a group of atoms that determine(s) the physical and chemical properties of a group of organic compounds.

Homologous series

A series of organic compounds that can be described by the same general formula OR in which one member differs from the next with a $CH_2$ group.

Structural isomer

Organic molecules with the same molecular formula, but different structural formulae.

Reaction rate

The change in concentration of reactants or products per unit time.

Le Chatelier's principle

When the equilibrium in a closed system is disturbed, the system will re-instate a new equilibrium by favouring the reaction that will oppose the disturbance.

Ampholyte (amphiprotic substance)

A substance that can act as either an acid or a base, such as water ( $H_2O$ ) or hydrogen sulfate ( $HSO_4^-$ ).

Oxidising agent

A substance that is reduced or gains electrons.

Reducing agent

A substance that is oxidised or loses electrons.

Eutrophication

The process by which an ecosystem becomes enriched with inorganic plant nutrients, especially phosphorus and nitrogen, resulting in excessive plant growth and oxygen depletion.

Standard Temperature and Pressure (STP) values

Standard Temperature is $273\,K$ ($0\,^{\circ}\text{C}$) and Standard Pressure is $1,01 \times 10^5\,Pa$ ($1\,\text{atm}$).

Faraday's law of induction

The emf induced is directly proportional to the rate of change of magnetic flux (flux linkage).

Lenz’s Law

The induced current flows in a direction so as to set up a magnetic field to oppose the change in magnetic flux.

Molar gas volume ($V_m$) at STP

$$22,4\,dm^3 \cdot mol^{-1}$$

Planck's constant ($h$)

$$6,63 \times 10^{-34}\,J \cdot s$$

Universal gravitational constant ($G$)

$$6,67 \times 10^{-11}\,N \cdot m^2 \cdot kg^{-2}$$

Empirical formula

The chemical formula of a compound that shows the smallest whole number ratio of the atoms.

Lactic acid as a monomer

Formed from biological fermentation of plant materials; it is used to create polylactic acid (PLA) which is biodegradable.

Haber Process Equation

$N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$ (where $\Delta H < 0$).

Ostwald Process Purpose

The industrial production of nitric acid ( $HNO_3$ ) via the catalytic oxidation of ammonia.