REPORT

  I. PRACTICAL TITLE

    TERMOKIMIA AND LEGAL HESS

 II. DATE AND TIME
    SATURDAY, 9 NOVEMBER 2016

III. OBJECTIVES OF EXPERIMENT
1. Measuring the heat of reaction with a simple tool.2. Collecting and analyzing thermochemical data.3. Apply the Hess law. 
Answer:A. Enthalpy is the sum of the energy of all forms of energy possessed by the substance whose quantity can not be measured.B. Isolated system is a system with its environment can not exchange both energy and material.C. Open systems are systems and environments can exchange energy and material.D. Closed system is a system which enables the transfer of energy (heat) to the environment, but can not transfer mass.E. The environment is anything outside the system that affects and limits the system.F. The calorimeter is the process of measuring the heat of the reaction / measuring the temperature change of a certain amount of water over the solution. As a result of a chemical reaction in an isolated container. 2. What is the difference in enthalpy with energy in (ΔE)?Answer:• Enthalpy is the sum total of all forms of energy possessed by the substance whose quantity can not be measured, whereas• Deep energy is the total amount of total potential energy and kinetic energy of substances contained in a system. 

V. THEORETICAL BASIS               
           Thermodynamics explains the relationship between heat and other forms of energy. Its development, which was an important scientific achievement in the 19th century, was due to the efforts of physicists and engineers who wanted to achieve high efficiency in a heat engine. The interest in improving the engine once again becomes important because of the necessity of using fossil fuels effectively. However, in the last 75 years, the important application of thermodynamics is in the field of chemistry. The law of thermodynamics is an important tool for studying chemical reactions. Thermochemistry is the influence of the heat that accompanies the chemical reaction. The second law of thermodynamics is primarily the basis for deriving the equilibrium constant of the properties of thermodynamic properties, in the third law of thermodynamics will be unveiled the starting point for looking at the properties of experimental thermodynamic properties (Petrucci.1987: 225).
                Each system has energy because the material particles (solid, liquid, or gas) always move randomly and diverse. There is translational motion, rotation, and ubrasi (vibrate). In addition, there may be a shift in the energy levels of electrons in atoms or molecules. Each movement, influenced by many factors and can change shape when colliding with each other. As a result, the energy of a particle's ganga will be different from the others. The total energy of all the particles will be different from the others. The total energy of all the particles in the system is called the inner energy (U). Therefore, the absolute value of U can not be calculated.               The first law of thermodynamics discusses the energy changes that accompany the event, and is useful for calculating the incoming or outgoing heat of the system. By equation: q = aU - w. The second law, to be discussed about spontaneous and non-spontaneous changes. The second law of thermodynamics sounds the natural process of adding natural entropy or entropy as it increases, and the third thermodynamic law sounds a pure element or compound in the form of perfect crystals having zero entropy at 0 ° C (Syukri.1999: 74).
               The application of the first law of thermodynamics to chemical events is called thermodynamics, which deals with the heat that accompanies chemical reactions. Chemical reactions include isothermal processes, and when done in the open air then the reaction calories qp = ΔH. Consequently, the heat can be calculated from the enthalpy change of the reaction q = ΔH = Result H-reaction. So that there should be a uniformity of standard conditions, ie temperature 25 ° C and pressure 1 Atm. Thus, thermodynamic calculations are based on standard conditions (Shukri.1999: 84).
               Thermochemistry is a part of thermodynamics that studies heat changes that follow chemical reactions. The amount of heat that arises or is required in a chemical reaction is called reaction heat. The heat of the reaction at P remains the same as the change in the ental strength, and the heat of reaction in U remains the same as the change in power.
The magnitude of the reaction pans depends on the type of reaction, the phase state of the substances in the reaction, the amount of the reacting agent, and the reaction temperature. In thermodynamic equations, the amount of substances in the reaction is expressed in moles while the heat is expressed in Kilocalories (Sukardjo 1990: 192).• Change of enthalpy (ΔH) and internal energy changes (ΔU) in chemical reactions.The reaction at constant pressure ΔH and heat of reaction at constant volume, ΔU is connected through the equation:ΔU = ΔH-PΔUIf the heat of reaction is carved under constant pressure conditions at a constant temperature of 298 K, it is -566.0 KJ, indicating that the 566.0 KJ energy has left the system as heat ΔH = -566.0 KJ. To evaluate the pressure-volume workPΔU = P (Vt -Vi)Then we can use the ideal gas equation. The kinetic equationPΔV = RT (nf-ni)Nf is the mole of gas in this product (2 moles CO2) is the number of moles of reactant solid gas (2 moles CO + 1 mole O2), soPΔV = 0,0083145 KJ / mol K-1. 298 K × [2 (2 + 1)] mol        = -2.5 KJInternal energy change isΔU = ΔH-PΔV     = -566,0KJ - (- 2,5KJ)     = -563.5KJ• Change of enthalpy (ΔH) accompanying material changes.When the liquid comes into contact with the atmosphere, energized molecules on the liquid surface can overcome the attraction with each other and enter the form of gas or steam.• Indirect determination ΔH: Hess's law of equilibrium of enthalpy changesΔH is an extensive natureHess's law concerning the sum of the constant heat (Petrucci.1992: 239-244).


VI. TOOLS AND MATERIALS
A. Tool
1. Measuring cup
2. Calorimeter
3. Mixer
4.Cup of trophies
B. material
1. 40 mL distilled water
2. 40 mL HCl 1 M
3. 40 mL NaOH 1M
4. 1M acetic acid
5. Sodium Hydroxide 1M
6. Sodium Acetate 1M
7. 1M Nitrate Acid
8. Ammonia 1M
A. Determination of calorimeter constants


VIII. OBSERVATION DATA
A. Determination of calorimeter constants
 
B. Determination of ΔH of neutralization for acid-base

IV. PRAKTEK QUESTIONS
1. Provide an understanding of: A) enthalpy; B) isolated system; C) open system; D) closed system; E) the environment; F) calorimeter; G) exothermic

  VII. WORK PROCEDURES



B. Determination of ΔH of neutralization for acid-base














IX. DISCUSSION  


         In this experiment the calorimeter is cleaned and dried. Enter 20 mL of distilled water into the calorimeter, record the weight and measure the temperature, then take 40 mL of distilled water with a measuring cup, heat and record the hot water weight. Combine hot water and cold water into the calorimeter, note the temperature. Result of experiment of determination of calorimeter constant, by formula:  

C.Mp (Tp-Tm)                             =   C.Md(Tm-Td)+ W(Tm-Td)

4,184 J/g°C.20(60°C-39°C)         =   4,184J/g°C.20(39°C-28°C) + W(39°C-28°C)

4,184 J/g°C (21°C)                      =   4,148J/g°C (11°C) + W (11°C)

87,864 J                                       =   46,024 J + 11 W



46,024 J                                       =   3,803 J°C



11 W                                            =   87,864 J –11 W                

    W                                              =   41,8   

B. Determination of ΔH of neutralization for acid-base


      In this experiment we made observations of different mixtures of acid-base solutions. After conducting an experiment in accordance with work procedures, the data obtained are:

1. The temperature of the basic solution (NaOH) = 30 ° C

Mixed temperature = 39 ° C

And get it:

Qreaksi = C. M. (Tf-Ti) + W (Tf-Ti)

            = 4.184.80 (30 -29.75) + (39 -29.75) .3,80

              = 334.72. (9,25) + 35,17

              = 3131.33 J

Qreaksi = -Range

-Round about = 3131.33 J

The equation of the reaction :




HCl + NaOH → NaCl + H2O

                                   

                               = 3131.33 J
         0.02 mol
                               = 156566,5J / mol



Then ΔH = reaction -Range around / The reacting mole
              = 3131.33 J /0.02 mol
              = 156566,5J / mol


2. The temperature of 1M CH3COOH acid solution: 26 ° C
The temperature of 1M NaOH base solution is: 30 ° C
Mixed temperature: 27 ° C
To get Qreaksi used formula:
Qreaksi = C. M. (Tf-Ti) + W (Tf-Ti)
              = 4.184J / g ° C.80gr (27 ° C-28 ° C) + (27 ° C-28 ° C)
                   . 3,803 J / ° C
              = -334,72 J / ° C. (-1 ° C) + (- 3,803 J)
              = -338,523 J
-Qsecured = Qreaksi
                   = -338,523 J
The reacting mole
CH3COOH + NaOH → NaCH3COO + H2O
Then ΔH = reaction -Range around / The reacting mole
              = 338,523  J /0.02 mol
              = 116926.15 J  / mol





X. DISCUSSION

A. DETERMINATION OF CALORYMETER STIPULATION     A calorimeter is a tool used to measure the heat of a reaction. While the heat absorbed by the calorimeter is called the calorimeter constant. The calorimeter constant can be determined by experimental temperature measurements on cold water, hot water, and a mixture of cold and hot water. Then we put the water into the calorimeter alternately to measure the temperature. After getting the temperature respectively, then we can determine the calorimeter constant that has been discussed in the discussion. From the discussion obtained the calorimeter constant (W) 3.803 J / ° C.Our group has determined from our experimental results that the calorimeter constant is 3.803J / ° C. This calorimeter constant is also used to determine ΔH neutralization. According to the theory of the determination of the calorimeter is 0 or the smaller the value the better the calorimeter used.So our experiments got results greater than zero. This experiment has been performed in accordance with work procedures, it's just possible tool error at the time of lab work, other things can also happen to praktikan 
itself.


XI. CONCLUSION

1. In measuring the reaction can use a simple


calorimeter.calorimeter constant, it takes data in the form

of weight,  Cheat type, and temperature of the substance.
2. To determine the calorimeter constant based 

on the black principle, the equation is:
C=Waterheattype4,14J/g°C
M=Weightofhotwater
Md=Coldwaterweight
Tp=Hotwatertemperature
Td=Coldwatertemperature
Tm=mixedtemperature
W = The calorimeter constant J / g
3. The calculation of heat of reaction can be done by using:
A. Hess's Law
B. Standard enthalpy entries
C. Average reactant energy

3. The calculation of heat of reaction can be done by using:

A. Hess's Law

B. Standard enthalpy entries

C. Average reactant energy



XII. 








































2. To determine the


C.MP. (Tp-Tm) =c.Md (Tm-Td) + W (Tm-Td)

information







XII. BIBLIOGRAPHY 

Agus. 2009.Kimia Dasar University.Jakarta:Erland. 

Petrucci, Raip H. 1992. Basic Chemistry.Jakarta: Erland 

Shukri. 1999. Basic Chemistry I. Bandung: ITB