What are the energy formulas involving specific heat mass and temperature change?

Answer 1

E = mass x sp ht x Δ°t (Finding Energy)where E (Energy) or Q (Quantity of Heat), mass (g), sp ht (aka specific heat, J/g°C*[typical] or cal/g°C or kcal/g°C), and Δ°t (temperature change). Finding Temperature ChangeDivide energy by mass multiplied by specific heat.

Δ°t = Energy

-- Mass * sp ht

In order to find the final temperature (if problem is asking for this), add or subtract the original temperature and the new temperature together.

Tf = original temperature +/- new temperature

If energy is added, the temperatures will be added together; if energy is removed, the temperatures will be subtracted.

Finding MassDivide energy by specific heat multiplied by temperature change.

Mass = Energy

------- sp ht * Δ°t

Finding Specific HeatDivide energy by mass multiplied by temperature change.

Sp ht = Energy

------- Mass * Δ°t

Converting Form of Energy (joules, kcal, and cal)Sometimes a problem will have E be shown in cal/g°C or kcal/g°C but will be asking for Joules or even vice versa. This means a conversion has to take place. Cal --> Joules and Joules --> cal-Calories (Cal) --> Joules (J)

Multiply # cal by 4.184 Joules (J).

Conversion Factor

# cal x 4.184 J = Joules

---------- 1 cal

1 cal = 4.184 Joules

-Joules (J) --> Calories (Cal)

Divide # Joules (J) by 4.184

Conversion Factor

# J x 1 cal = cal

--- 4.184 J

1 Joule = 0.239005736 cal

Kcal --> Joules (J) and Joules (J) --> Kcal-Joules --> kcal (Joules --> cal --> kcal)

Divide # J by # kcal multiplied by 103

Conversion Factor

# Joules x 1 cal - * - 1kcal = kcal

---------- 4.184J -- 103 cal

1 kcal = 4,184 Joules <--> 1 Joule = 0.000239005736 kcal

-Kcal --> Joules (J) (Kcal --> cal --> Joules)

Multiply # kcal by 103 cal by 4.184J

Conversion Factor

# kcal * 103 cal * 4.184J = Joules (J)

----------- 1 kcal --- 1 cal

Another relationship that is good to understand: 1 kcal = 1000 (103) cal <--> 1 cal = 0.001 (10-3) kcal