Use this formula: Q=(m)(∆T)(Csp), where Q is heat (what you’re solving for), m is mass in grams (g), ∆T is the change in temperature (ending temp. minus beginning temp.) in degrees Celsius (∘C), and Csp is the specific heat capacity in joules per gram per degree(J/g ∘C). The answer will be in joules of energy (J). Just multiply all three quantities given in the text together (as it shows in the formula!) to get Q. But remember, you have to figure out the change in temperature (like 10 ∘C to 50 ∘C is a change of 40 ∘C).

1. A calorimeter holds 75 g water at 26°C. A sample of hot copper is added to the water. The final temperature of the water and copper is 39°C. What is the change in enthalpy associated with the change in the water’s temperature? The specific heat capacity of water is 4.19 J/g°C.

2. A chemist heats a 215-g sample of iron from 25.0°C to 90.0°C. How much heat did the iron absorb? The specific heat capacity of iron is 0.45 J/g°C.

1. Q = 4085.25 J

2. Q = 6288.75 J

Heat can be calculated using the formula:  

Q = mc∆T  

A calorimeter is a device used to measure the specific heat of material  

1. mass of water : m= 75 g

T1 = 26°C

T2 = 39°C

Csp = 4.19 J/g°C.

2.mass of iron = 215 g

T1 = 25°C

T2 = 90°C

Csp = 0.45 J/g°C.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.