This chapter explains matter, its properties, and its different states. Understanding matter is essential as it forms the basis of all physical substances around us.
MATTER IN OUR SURROUNDINGS – Formula & Equation Sheet
Essential formulas and equations from Science, tailored for Class 9 in Science.
This one-pager compiles key formulas and equations from the MATTER IN OUR SURROUNDINGS chapter of Science. Ideal for exam prep, quick reference, and solving time-bound numerical problems accurately.
Key concepts & formulas
Essential formulas, key terms, and important concepts for quick reference and revision.
Formulas
Density = mass/volume
Density (ρ) is the mass (m) of a substance divided by its volume (V). Density is used to determine how compact a substance is, and it helps in identifying materials.
Latent Heat of Fusion = Q/m
Q is the heat energy absorbed or released, and m is the mass of the substance. This formula calculates the energy needed to change a substance from solid to liquid at its melting point without changing its temperature.
Latent Heat of Vaporization = Q/m
Similar to fusion, this formula calculates the energy required to change a substance from liquid to gas at its boiling point. Here, Q denotes the heat energy, and m is the mass.
Boiling Point (atmospheric pressure) = 100 °C = 373 K
This indicates the temperature at which a liquid changes to a gas. The boiling point varies based on atmospheric pressure.
Melting Point of Ice = 0 °C = 273 K
This is the temperature at which ice converts to water. The melting point indicates the strength of the molecular attractions in solids.
E = mc²
E represents energy (in joules), m is mass (in kg), and c is the speed of light (≈ 3 × 10⁸ m/s). This formula from relativity indicates the equivalence of mass and energy.
V = IR (Ohm’s Law)
V is voltage (volts), I is current (amperes), and R is resistance (ohms). Used in electrical calculations involving circuits.
P = F/A
P represents pressure, F is the force applied, and A is the area. Pressure is crucial in understanding gases and fluid behavior.
v ∝ T (for gases, at constant pressure)
This law states that the volume (v) of a gas is directly proportional to its absolute temperature (T) at constant pressure. Useful for studying gas behavior.
v ∝ 1/P (for gases, at constant temperature)
This law indicates that the volume (v) of a gas is inversely proportional to its pressure (P) at constant temperature. Important for understanding gas compression.
Equations
Density = mass/volume
This equation calculates the density of a substance, which is vital for identifying materials based on their compactness.
Q = mcΔT
Where Q is the heat energy, m is mass, c is specific heat capacity, and ΔT is the change in temperature. This equation helps in calculating the heat required to change the temperature of a substance.
p = ρgh
Where p is pressure, ρ is density, g is acceleration due to gravity, and h is height. Used for calculating fluid pressure.
Boyle's Law: PV = constant
This equation describes the inverse relationship between the pressure (P) and volume (V) of a gas at constant temperature.
Charles's Law: V/T = constant
This law states that at constant pressure, the volume (V) of a gas is directly proportional to its absolute temperature (T).
Q = mLv (latent heat of vaporization)
This formula represents the heat energy (Q) required to vaporize a mass (m) of liquid at constant temperature, where Lv is the latent heat of vaporization.
Q = mLf (latent heat of fusion)
This formula indicates the heat energy (Q) required to melt a mass (m) of solid at constant temperature, where Lf is the latent heat of fusion.
V = nRT/P (Ideal Gas Law)
V is volume, n is the number of moles, R is the universal gas constant, T is temperature, and P is pressure. This formula helps understand the behavior of ideal gases.
F = ma
F represents force, m is mass, and a is acceleration. Fundamental in understanding motion and energy.
ΔH = q
This equation relates the change in enthalpy (ΔH) to the heat (q) transferred at constant pressure, often used in chemical reactions involving heat.
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