core 5 - p1 Flashcards
(20 cards)
What are the three main subatomic particles in an atom, and where are they located?
Protons (in the nucleus), neutrons (in the nucleus), and electrons (in shells around the nucleus).
Define valency.
Valency describes how easily an atom can combine with another atom by gaining, losing, or sharing electrons. It is denoted by a positive or negative integer.
What is the difference between a cation and an anion?
A cation is a positively charged ion (formed by losing electrons), while an anion is a negatively charged ion (formed by gaining electrons).
Explain the role of the valence shell in chemical bonding.
The valence shell contains electrons that participate in bond formation. These electrons can be lost, gained, or shared with other atoms.
What is the formula for hydrostatic pressure, and what do the variables represent?
P=ρgh, where ρ = fluid density (kg/m³), g = gravitational acceleration (9.81 m/s²), and h = depth of the fluid (m).
Calculate the hydrostatic pressure at a depth of 3 meters in water (
ρ
=
1000
kg/m
3
ρ=1000kg/m³).
P=1000×9.81×3=29,430Pa (or 29.43 kPa).
What is the primary difference between a primary cell and a secondary cell?
Primary cells are non-rechargeable (irreversible reaction), while secondary cells are rechargeable (reversible reaction).
Describe electrolysis.
Electrolysis is the process of using an electric current to drive a non-spontaneous chemical reaction, decomposing ionic compounds into their elements.
State Bernoulli’s principle.
An increase in fluid speed occurs with a decrease in pressure or a decrease in the fluid’s potential energy.
How does thermal expansion affect railway tracks?
Gaps are left between railway tracks to prevent buckling due to expansion in hot weather.
What are the three mechanisms of heat transfer?
Conduction (direct contact), convection (fluid movement), and radiation (electromagnetic waves).
A steel pipe (α = 16×10 ^ −6 K ^ −1 ) is 20 m long at 20°C. Calculate its length at 100°C.
ΔL=20×16×10 ^ −6
× (100−20)=0.0256m.
New length = 20+0.0256=20.0256m.
Define moment of inertia.
It measures an object’s resistance to rotational motion, calculated as I=∑mr ^ 2, where m = mass and r = distance from the axis.
What is the equation for gravitational force?
W=mg, where W = weight (N), m = mass (kg), and g = 9.81 m/s².
A car (mass = 1500 kg) decelerates from 30 m/s to 0 m/s in 5 seconds. Calculate the braking force.
a=(0−30)/5=−6m/s ^ 2
F=ma=1500×(−6)=−9000N (9000 N opposing motion).
What is the difference between a solution and a suspension?
A solution is homogeneous (e.g., saltwater), while a suspension has larger particles that settle out (e.g., sand in water).
How does galvanic protection prevent corrosion?
How does galvanic protection prevent corrosion?
Name the four types of chemical reactions listed in the PDF.
Synthesis, decomposition, single replacement, and double replacement.
What is the formula for rotational kinetic energy?
E rot = 1/2 Iω^2, where I = moment of inertia and ω = angular velocity.
Define specific latent heat of fusion.
The energy required to change 1 kg of a substance from solid to liquid at its melting point, without temperature change.
