Formula Sheet: Changes Around Us: Physical and Chemical

E represents energy (in joules), m is mass (in kg), and c is the speed of light (≈ 3 × 10⁸ m/s). This formula shows how mass can be converted into energy, a foundational idea in Einstein’s theory of relativity.

Q indicates heat energy (in joules), m is mass (in kg), c is specific heat capacity (J/kg·°C), and ΔT is the change in temperature (in °C). This formula determines the amount of heat required to change the temperature of a substance.

p is density (kg/m³), m is mass (in kg), and V is volume (in m³). This formula relates mass and volume to calculate the density of a substance.

R is resistance (in ohms), ρ is resistivity (Ω·m), L is length of the conductor (in m), and A is cross-sectional area (in m²). This formula finds the resistance of a conductor based on its material and dimensions.

C represents capacitance (in farads), Q is charge (in coulombs), and V is voltage (in volts). It is used to determine the ability of a system to store electrical energy.

V is voltage (in volts), I is current (in amperes), and R is resistance (in ohms). This formula defines the relationship between current and voltage in a circuit.

P is pressure (in pascals), V is volume (in m³), n is the amount of substance (in moles), R is the ideal gas constant, and T is temperature (in kelvins). This equation explains the relationship in an ideal gas.

ΔS is entropy change (J/K), ΔH is enthalpy change (in joules), and T is temperature (in kelvins). This formula relates the changes in entropy to enthalpy and temperature.

This chemical equation represents the reaction between hydrogen and oxygen to form water. It shows the conservation of mass in chemical reactions.

This equation represents the rusting process where iron reacts with oxygen to produce iron oxide, commonly known as rust.

This equation represents the reaction in which lime water (calcium hydroxide) reacts with carbon dioxide to form calcium carbonate (a cloudy precipitate) and water.

This reaction produces carbon dioxide gas when vinegar reacts with baking soda, resulting in bubbling and fizzing.

This equation shows the combustion of magnesium in oxygen, producing magnesium oxide along with the release of heat and light.

This equation signifies the physical change of water from liquid (l) to gas (g) through evaporation.

This is the combustion reaction of propane (C₃H₈) in oxygen that produces carbon dioxide and water, releasing energy in the form of heat.

This equation describes the formation of rust, where iron reacts with oxygen to form iron oxide.

This equation shows the thermal decomposition of calcium carbonate into calcium oxide and carbon dioxide upon heating.

This balanced reaction indicates the synthesis of water from hydrogen and oxygen, highlighting the conservation of mass.

This equation represents the synthesis of ammonia, a crucial process in chemistry, emphasizing stoichiometry in reactions.

This equation describes the hydrolysis of sucrose (table sugar) into glucose, demonstrating the chemical change during digestion.