8TH GRADE · THERMAL PHENOMENA
Amount of heat and heat balance
Specific heat capacity, calorimeter, fuel and energy conservation.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
Heat
Energy transferred to or given up by a body during the process of heat transfer.
When heated without a phase transition, the amount of heat depends on the mass, heat capacity of the substance and temperature change.
Calorimeter and heat balance
The calorimeter reduces the exchange with the environment, and in a closed system the heat given is equal to the heat received.
To determine specific heat capacity, mass and temperature are measured, then a balance equation with a single sign is drawn up.
Fuel energy
When fuel burns completely, energy is released that is proportional to its mass and specific heat of combustion.
The actual installation transfers only part of the energy to the useful body, but the general law of conservation of energy is not violated.
Physical quantities
Heat
Energy received or given off by a body during heat transfer.
Unit: joule ·
Body weight
The mass of the substance involved in heat exchange.
Unit: kilogram ·
Specific heat capacity
Energy to heat one kilogram of a substance by one kelvin.
Unit: joule per kilogram kelvin ·
Temperature change
The difference between the final and initial body temperatures.
Unit: kelvin ·
Specific heat of combustion
Energy released during complete combustion of a unit mass of fuel.
Unit: joule per kilogram ·
Lesson formulas
Heating and cooling
The amount of heat is equal to the product of specific heat capacity, mass and temperature change.
Condition: No phase transition; The heat capacity is assumed to be constant.
Heat balance
In a thermally insulated system, the algebraic sum of the received and released heat is zero.
Heat of combustion
With complete combustion, the amount of heat is equal to the specific heat of combustion multiplied by the mass of the fuel.
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.