A 150 g sample of brass at 90.0 degrees Celsius is placed in a calorimeter cup that contains 230 g of water at 20.0 degrees Celsius. Disregard the absorption of heat by the cup and calculate the final temperature of the brass and water. Specific heat of water = 4.18 J/gC, specific heat of brass=0.380 J/gC.

for brass

mass m1 =150g

t1=90°c

specific heat of brass s1=0.380 J/gC.

for water

t2=20°c

mass m2=230g

Specific heat of water s2= 4.18 J/gC,

Explanation:

we have

Q1=Q2

m1s1{t-t1)=m2s2(t2-t)

150×0.380(t-90)=230×4.18(20-t)

57t-5130=961.4×20-961.4t

57t +961.4t=19228+5130

1018.4t=24358

t=24358/1018.4=23.91=24°c is final temperature

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.