Heat Transfer Calculator

Calculate heat energy transfer using the formula Q = mcΔT. Essential for thermodynamics, calorimetry, and understanding energy transfer in physics and chemistry.

**Heat Transfer Formula:** Q = m × c × ΔT Where: • Q = Heat energy transferred (Joules, J) • m = Mass of substance (kg) • c = Specific heat capacity (J/kg·°C or J/kg·K) • ΔT = Temperature change (°C or K) **Rearrangements:** • Mass: m = Q / (c × ΔT) • Temperature change: ΔT = Q / (m × c) • Specific heat: c = Q / (m × ΔT) **Unit Conversions:** • 1 cal = 4.184 J • 1 kcal = 4184 J = 1 food Calorie • 1 kWh = 3.6 MJ = 860 kcal **Note:** This formula applies to temperature changes WITHOUT phase changes (no melting, freezing, boiling, or condensing).
**Example 1 (Heating Water):** How much energy to heat 2 kg of water from 20°C to 100°C? • Mass = 2 kg • Specific heat = 4186 J/kg·°C (water) • Temperature change = 80°C • Q = 2 × 4186 × 80 = 669,760 J ≈ 670 kJ **Example 2 (Cooling Metal):** An aluminum block (0.5 kg, c = 900 J/kg·°C) releases 13,500 J cooling down. • Mass = 0.5 kg • Specific heat = 900 J/kg·°C • Heat = 13,500 J • ΔT = 13,500 / (0.5 × 900) = 30°C temperature drop **Example 3 (Finding Mass):** 100,000 J heats copper by 50°C. What's the mass? (c = 385 J/kg·°C) • Heat = 100,000 J • Specific heat = 385 J/kg·°C • Temperature change = 50°C • m = 100,000 / (385 × 50) = 5.19 kg **Example 4 (Thermal Equilibrium):** Mix 1 kg water at 80°C with 2 kg water at 20°C. Heat lost = Heat gained 1 × 4186 × (80 - T_f) = 2 × 4186 × (T_f - 20) Final temperature T_f = 40°C

What is heat transfer?

Heat transfer is the movement of thermal energy from a hotter object to a cooler one. The amount of heat transferred depends on mass, specific heat capacity, and temperature change, calculated using Q = mcΔT.

What is specific heat capacity?

Specific heat capacity (c) is the energy needed to raise 1 kg of a substance by 1°C. Water has high specific heat (4186 J/kg·°C), meaning it takes lots of energy to heat up. Metals typically have lower values.

What are the three modes of heat transfer?

Conduction: heat transfer through direct contact (touching a hot pan). Convection: heat transfer through fluid motion (boiling water). Radiation: heat transfer through electromagnetic waves (sun warming your face).

How do I convert between Joules and calories?

1 calorie = 4.184 Joules. The "calorie" in nutrition (kilocalorie or kcal) equals 4184 J. This calculator shows both units for energy calculations.

What is the difference between heat and temperature?

Temperature measures average kinetic energy of particles (°C or K). Heat is the total thermal energy transferred (Joules). A large cool object can contain more heat than a small hot object.

Why is water's specific heat important?

Water's high specific heat (4186 J/kg·°C) makes it excellent for temperature regulation. Oceans moderate climate, and your body uses water to maintain stable temperature. It also makes water-based cooling systems very effective.

Can I use this for phase changes?

No, Q = mcΔT only works when temperature changes without phase change. For melting/freezing or boiling/condensing, you need latent heat formulas: Q = mL, where L is latent heat of fusion or vaporization.

What are common specific heat values?

Water: 4186 J/kg·°C, Ice: 2090 J/kg·°C, Aluminum: 900 J/kg·°C, Copper: 385 J/kg·°C, Iron: 450 J/kg·°C, Air: 1005 J/kg·°C, Concrete: 880 J/kg·°C, Wood: ~1700 J/kg·°C.

How does heat transfer relate to thermodynamics?

Heat transfer is governed by the First Law of Thermodynamics: ΔU = Q - W, where ΔU is internal energy change, Q is heat added, and W is work done. For constant volume processes, Q = ΔU = mcΔT.

What is thermal equilibrium?

Thermal equilibrium occurs when two objects reach the same temperature and heat transfer stops. The heat lost by the hotter object equals the heat gained by the cooler object: m₁c₁ΔT₁ = m₂c₂ΔT₂.

How do insulators affect heat transfer?

Insulators (low thermal conductivity) slow heat transfer by conduction. Good insulators like fiberglass, foam, or air gaps reduce heat flow, making them essential for energy-efficient buildings and thermoses.

What is the difference between sensible and latent heat?

Sensible heat causes temperature change (Q = mcΔT). Latent heat causes phase change at constant temperature (Q = mL). Both transfer energy, but only sensible heat changes temperature.