Sound Basics
A student claims a louder sound means higher pitch. Critique their statement.
Loudness relates to amplitude, not pitch. Pitch is linked to frequency.
A dolphin and a bat both use echolocation. Analyze how their environments influence echolocation frequency.
Dolphins use water—denser medium, lower frequency; bats use air—higher frequency for short range.
A chemist separates a substance into hydrogen and oxygen through electrolysis. What does this tell you about the original substance, and why?
It’s a compound, likely water, because it decomposes into simpler elements—indicating it has chemically bonded elements.
What is meant by the term 'chemical formula'? What does H₂SO₄ tell you about the compound?
It’s a symbolic representation of a compound’s composition. H₂SO₄ has 2 hydrogen, 1 sulfur, and 4 oxygen atoms.
This element has isotopes with mass numbers of 12, 13, and 14.
carbon
Compare sound propagation in solids vs gases using particle theory.
n solids, particles are closely packed, so sound travels faster than in gases.
Propose a scenario where the Doppler Effect could help identify a medical condition.
In echocardiography, Doppler shift helps assess blood flow abnormalities.
Classify steel and justify why it's not a pure substance.
It’s a mixture/alloy—contains multiple elements not chemically bonded.
If a solution appears clear but is made from two liquids, how can you confirm it's homogeneous?
Use filtration or microscope—no separate phases means homogeneous.
What is the atomicity of ozone (O₃), and why is it different from that of oxygen (O₂)?
Ozone has an atomicity of 3, consisting of three oxygen atoms. This occurs because ozone molecules form when three oxygen atoms bond together in a particular configuration, unlike the diatomic form of oxygen.
Two waves with same amplitude reach your ear; one feels "sharper." Hypothesize why.
Likely due to higher frequency, which our brain interprets as sharper pitch.
Design a method using sound waves to detect underground tunnels.
Emit pulses and analyze reflected waves for delays or anomalies indicating empty space.
You’re given three clear liquids: pure water, saltwater, and ethanol. How would you determine which is the pure substance?
Use evaporation and boiling point testing—pure substances have fixed boiling points; mixtures do not.
Why do elements in the same group (column) of the periodic table have similar chemical properties?
Elements in the same group have the same number of valence electrons, which determine their chemical reactivity and bonding behavior.
What is the ionic bond, and how is it formed? Give an example.
An ionic bond is formed when electrons are transferred from one atom to another, resulting in the attraction between oppositely charged ions. Example: Sodium chloride (NaCl)
Evaluate how sound behaves in space and explain using a scientific model.
n space, there's no medium for particles to vibrate, so sound cannot travel—vacuum.
How could sound waves be used to detect cracks inside metal railway tracks without breaking them apart?
Use ultrasonic testing—high-frequency sound waves are sent through the metal; reflections from cracks indicate flaws.
Which separation technique would you use for: (a) iron and sand, (b) salt and water?
(a) Magnetic separation, (b) Evaporation.
What is the significance of the electron configuration of an atom in determining its chemical behavior?
The electron configuration determines how an atom will bond with other atoms. Atoms with similar electron configurations (especially in the outer shell) have similar chemical properties.
For chlorine, Z = 17, A = 35. Give the number of protons, electrons and neutrons in chlorine atom.
17 protons
17 electrons
18 neutrons
A car horn sounds different when heard inside the car and outside on the street. Explain why this happens in terms of sound wave transmission.
Inside the car, sound waves are reflected and absorbed differently due to materials and space. Outside, sound spreads more freely and may lose intensity or frequency components.
Analyze why whales use low-frequency sound for long-distance communication.
Low-frequency waves have longer wavelengths, which can travel farther through water with less energy loss
Identify whether the following are elements, compounds, or mixtures:
(a) Copper wire
(b) Milk
(c) Carbon dioxide
(d) Salt Water
(a) Element, (b) Heterogeneous Mixture,
(c) Compound, (d) Homogeneous Mixture.
If an atom has 6 protons, 6 neutrons, and 6 electrons, how would you describe its atomic structure?
This is a neutral atom of carbon (C), with 6 protons and 6 electrons, and its atomic mass would be approximately 12 (the sum of protons and neutrons)
An atom of an element has two electrons in outermost M-shell. State its (a) Electronic configuration (b) Number of protons (c) Atomic number (e) Valency (f) Name
(a) Electronic configuration: 2, 8, 2
(b) Number of protons: 12
(c) Atomic number: 12
(e) Valency: 2
(f) Name: Magnesium