Chemistry
What subatomic particle determines the identity of an element? [20 seconds, no calculator]
Protons.
State the fundamental law of magnetic attraction and repulsion regarding magnetic poles. [20 seconds, no calculator].
Like poles repel each other, and unlike (opposite) poles attract each other.
State the fundamental law of magnetic attraction and repulsion regarding magnetic poles. [20 seconds, no calculator].
Like poles repel each other, and unlike (opposite) poles attract each other.
Define an isotope. [25 seconds, no calculator]
Atoms of the same element with the same number of protons but different numbers of neutrons.
What is the main organ of the breathing system? [15 seconds, no calculator]
The lungs.
What is the difference between atomic number and mass number? [35 seconds, no calculator]
Atomic number is the number of protons.
Mass number is the number of protons plus neutrons.
What process describes how species change over time? [15 seconds, no calculator]
Evolution
Describe the law of reflection concerning the angle of incidence and the angle of reflection.
Time: 45 seconds, no calculator
The law of reflection states that the angle of incidence is exactly equal to the angle of reflection.
What ion do acids release when dissolved in water? [30 seconds, no calculator]
Hydrogen ions (H⁺)
What is the term for the process where gases are swapped between the human body and the atmosphere? [20 seconds, no calculator]
Gas Exchange
An atom has 17 protons, 18 neutrons and 17 electrons.
State:
a) Atomic number
b) Mass number
[60 seconds, no calculator]
a) 17
b) 35
If an object is lifted higher up off the ground, what specific type of energy store increases, and what force causes this?
Time: 45 seconds, no calculator
Its gravitational potential energy store increases, and this is caused by the earth gravitational force pulling down on it.
Explain the structural difference between a "soft" magnetic material (like soft iron) and a "hard" magnetic material (like steel) in terms of how easily they retain magnetism. [45 seconds, no calculator] .
Soft magnetic materials are easily magnetized but lose their magnetism quickly (temporary magnets). Hard magnetic materials are difficult to magnetize but retain their magnetism for a long time (permanent magnets).
Explain why elements in the same group have similar chemical properties. [60 seconds, no calculator]
Elements in the same group have the same number of valence (outer-shell) electrons, so they react in similar ways.
During inhalation, what happens to the diaphragm and intercostal muscles? [40 seconds, no calculator]
They contract
Compare metals and non-metals by giving two properties of each. [90 seconds, no calculator]
Metals (any two):
Lustrous/shiny
Malleable
Good conductor of electricity
Good conductor of heat
Non-metals (any two):
Dull
Poor conductor of electricity
Poor conductor of heat
Brittle
What is a solenoid, and what are two specific adjustments you can make to its electrical setup to increase the strength of its magnetic field? [60 seconds, no calculator] .
A solenoid is a long coil of wire. You can increase its strength by increasing the electric current, increasing the number of turns on the coil, or inserting a soft iron core into the center.
State the wave equation that relates wave speed, frequency, and wavelength. Time: 45 seconds, no calculator
Answer: Wave speed equals frequency multiplied by wavelength.
Describe what happens during neutralisation. [60 seconds, no calculator]
An acid reacts with an alkali, reducing their acidity and alkalinity until a neutral solution is produced.
What is the difference between breathing and respiration? [35 seconds, no calculator]
Breathing is the physical act of taking in/removing air, while respiration is a chemical reaction in cells that requires oxygen.
A student claims that if an atom gains two neutrons, it becomes a completely different element.
Evaluate this statement. [2 minutes, no calculator]
The statement is incorrect. An element is determined by its number of protons. Adding neutrons changes the isotope, not the element.
If the pressure in the lungs stayed the same as the surrounding atmosphere, what would happen? [1 minute, no calculator]
Air would not move into or out of the lungs.
A specialized electromagnet used in a particle accelerator is cooled using liquid helium to remove all electrical resistance. If the normal room-temperature resistance allowed a maximum current of 5 A across a 20-turn coil, but the cooled super-conducting wire allows the current to increase by a factor of 12 under the same voltage, calculate the new operational current. [90 seconds, calculator allowed].
The calculation is 5 A × 12 = 60 A. The new operational current is 60 Amperes.
A cleaner has a pH of 13 and lemon juice has a pH of 2. Which substance is more hazardous to skin and why? [90 seconds, no calculator]
Both can be hazardous because they are far from neutral. However, the cleaner is likely more hazardous because pH 13 indicates a very strong alkali that can cause severe chemical burns.
Explain how giraffes’ neck length is an example of natural selection. [1 minute 30 seconds, no calculator]
Individuals with longer necks have better access to food, increasing survival. They survive longer to reproduce, passing the trait for longer necks to their offspring.