Name : Fenton
Martin
Class : XI A IM
No : 8 ( eight
)
Group : 1 ( Frist Group )
Day
and Date : Thursday, 22 September 2011
Title : Determine ΔH Reactions Calorimeter
SMA
NEGERI 1 KROYA
I.
Purpose
: To calculate the reactions
through the trial
II.
Tools
and Materials :
1.
Calorimeter : 1 pieces
2.
Themometer 100°C : 2 pieces
3. Stirer : 1 pieces
4.
Measuring
cups 50 Ml : 2 pieces
5. A solution of NaOH 1M :50mL
6. A solutions of HCL 1M :50 mL
III.
Basic
Theory :
A thermometer is an instrument for measuring
temperature.Mercury thermometers are the types of thermometers are often used
by the common people. Mercury
used in thermometers measure temperature because the coefficient can be
calculated muainya constant so that changes in volume resulting from the
increase or decrease in temperature is almost always the same.
This device consists of a capillary tube using a glass material containing mercury at the lower end. For measurement purposes, the pipe is made in such a way that the vacuum. If the temperature increases, the mercury will expand up towards the top of the pipe and provide clues about the temperature around the measuring instrument in accordance with a scale that has been determined.Temperature scale the most widely
used worldwide is the Celsius scale with 0 points to the
freezing point and boiling point 100 to point.
Mercury thermometers were first made by Daniel G. Fahrenheit.This heat sensor equipment using materials Mercury and glass pipe with Celsius and Fahrenheit scale for measuring temperature.In 1742 Anders Celsius published a book titled "The discovery of Celsius Temperature Scale" which describes the calibration method between devices such as thermometers below:
Place the thermometer in the water cylinder that is melting and mark the point when all the water thermometer is entirely liquid.This point is the freezing point of water.
In the same way, mark the point when the entire thermometer boiling water completely when heated.
For the length of the two points above the one hundred equal parts.
Until now, three points above the calibration is still used to find the average on the Celsius scale mercury thermometer. These points can not be used as an accurate calibration method for boiling point and freezing point of water varies as the pressure difference.
How it Works:
Prior to the change in temperature, the volume of mercury is in the initial conditions.
Changes in ambient temperature around the thermometer Mercury responded with volume changes.
The volume of mercury will expand if the temperature increases and will shrink when the temperature decreases.
The scale on the thermometer will indicate the temperature values according to environmental circumstances.
This device consists of a capillary tube using a glass material containing mercury at the lower end. For measurement purposes, the pipe is made in such a way that the vacuum. If the temperature increases, the mercury will expand up towards the top of the pipe and provide clues about the temperature around the measuring instrument in accordance with a scale that has been determined.Temperature scale the most widely
Mercury thermometers were first made by Daniel G. Fahrenheit.This heat sensor equipment using materials Mercury and glass pipe with Celsius and Fahrenheit scale for measuring temperature.In 1742 Anders Celsius published a book titled "The discovery of Celsius Temperature Scale" which describes the calibration method between devices such as thermometers below:
Place the thermometer in the water cylinder that is melting and mark the point when all the water thermometer is entirely liquid.This point is the freezing point of water.
In the same way, mark the point when the entire thermometer boiling water completely when heated.
For the length of the two points above the one hundred equal parts.
Until now, three points above the calibration is still used to find the average on the Celsius scale mercury thermometer. These points can not be used as an accurate calibration method for boiling point and freezing point of water varies as the pressure difference.
How it Works:
Prior to the change in temperature, the volume of mercury is in the initial conditions.
Changes in ambient temperature around the thermometer Mercury responded with volume changes.
The volume of mercury will expand if the temperature increases and will shrink when the temperature decreases.
The scale on the thermometer will indicate the temperature values according to environmental circumstances.
IV.
Work
Steps :
1.
Take
2 pieces measuring cups, each input into it:
v
Glasses 1 : 50 mL NaOH 1
M and measure it’s temperature ( initial
temperature )
v Glasses 2 : 50 mL HCL 1 M and measure
it’s temperature ( initial temperature )
2. Pour the solution into the calorimeter,
stir with a thermometer ( slowly ), while continuing to observe the
temperature. Themperatures wiil rise and than be fixed and then descended.
Record the temperature fixed ( final temperature ).
V.
Observations
:
Initial Temperature
|
Final Temperature
|
Temperature Changes
|
T₁ HCL 1M= 27°C
T₁ NaOH 1M = 31°C
T₁ mean = 29°C
|
The temperature of the
solution after the intervention
T₂=33°C
|
ΔT = T₂
- T₁
= 33-29 °C
=306-302 °K
= 4 °K
|
VI.
Calculation
/ Reaction / Discussion :
1.
Volume
of the solution = volume HCL + voleme NaOH = 100 mL
2. The density of the solution is
considered equal to the density of water = 1 g/mL
Masses solutions ( m ) = volume of
solution x density of water = 100 mL x 1 g/mL= 100 gr
3. Heat generated from the
experiment,
q = m c ΔT
= 100 x 4,2 x
4 = 1680 Joule
4.
50
mL NaOH 1 M =
= =
0,05 mol NaOH
5. Based on the equation : NaOH(aq) +
HCL(aq) →NaCl(aq) + H2O(I)
0,05 mol NaOH
= 0,05 mol HCL = 0,05 mol H2O
6. Based on the results of the experiment ΔH reaction = -q = - 1680
For the
reaction : NaOH(aq) + HCL(aq) →
NaCl(aq) +
H2O(I)
ΔH reaction =
=
= - 33600 kJ
= - 33.6 kJ
Discussion :
In the lab yesterday, our group experienced a problem with the T1 (initial temperature) is not something with the standards of other groups, so we must repeat our lab so that our group can have a number of the initial temperature according to existing standards.
Over our mistakes, we apologize
Conclusion :
Of practicum in the above, we can draw the conclusion that, in seeking ΔH we can also use the thermometer, in addition to using the formula alone.
Question :
1. How does the sign for ΔH reaction?
2. These reactions include the reaction eksotermic or endotermic?
3. Write the thermochemical equation for the reaction!
In the lab yesterday, our group experienced a problem with the T1 (initial temperature) is not something with the standards of other groups, so we must repeat our lab so that our group can have a number of the initial temperature according to existing standards.
Over our mistakes, we apologize
Conclusion :
Of practicum in the above, we can draw the conclusion that, in seeking ΔH we can also use the thermometer, in addition to using the formula alone.
Question :
1. How does the sign for ΔH reaction?
2. These reactions include the reaction eksotermic or endotermic?
3. Write the thermochemical equation for the reaction!
1. ΔH values also can be determined by the reduction of the formation enthalpy of the products minus the
enthalpy of formation
ofreactants. Mathematically:
For other reactions in general:
2.
the exothermic reaction, because liberate energy system, so the enthalpy ofthe
system will be reduced, meaning that the product enthalpy is smaller than
the enthalpy of reactants. Therefore, enthalpy changesare
negative. So that p can be
expressed as follows:
ΔH = Hp-Hr <0
ΔH = Hp-Hr <0
3. NaOH(aq)
+ HCL(aq) → NaCl(aq)
+ H2O(I) ΔH = - 33.6 kJ
Bibliography
Fred Landis Microsoft Encarta Reference Library 2005
http://en.wikipedia.org/wiki/Thermometer
http://en.wikipedia.org/wiki/Thermometer
Kroya, 29 September 2011
Knowing that : who
maker :
Pak Waryanto S.Pd. Fenton
Martin
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