Docsity
Log inSign up
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search Store documents

The best documents sold by students who completed their studies

Search through all study resources
Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

University Rankings

Discover the best universities in your country according to Docsity users

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

From our blog

Exams and Study
Go to the blog

Phase Diagram of Naphthalene-Diphenylamine System: An Experimental Study, Thesis of Chemistry

Feati University (FU)Chemistry

Rank the following 0.1 M salt solutions in order of increasing pH (lowest pH at the top of the list). Instructions

Typology: Thesis

2021/2022

Uploaded on 10/15/2022

jackantanoof
jackantanoof 🇵🇭

2 documents

1 / 4

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
Solid-Liquid Phase Diagram
of Naphthalene-Diphenylamine Two-Component System
Michael Go, Nate Manaloto, Ronald Reyes*
*Faculty, Ateneo de Manila University; email: ron_rxn24@yahoo.com
Abstract. The experiment aims to be able to construct a phase diagram of
Naphthalene-Diphenylamine two-component system at constant atmospheric
pressure for thermal analysis. From the phase diagram, the eutectic composition
(XE) and eutectic temperature (TE) are determined and are compared with the
literature value. Commercial Naphthalene is used to undergo this test, and see if it
is of the same caliber as the standard Naphthalene.
Keywords. Naphthalene-Biphenylamine. Eutectic point. Newton’s Law of Cooling. Thermal Arrest. Thermal Break.
Introduction. In investigating the heterogeneous
equilibrium between solid and liquid phases of a two-
component system, a phase diagram is constructed. In
constructing phase diagrams, cooling curves forms
the basis for “thermal analysis”. From the phase
diagram, the eutectic composition (XE) and eutectic
temperature (TE) are determined.
Figure 1. A Phase Diagram for a two component system in
which the solids are partially miscible and the liquids are
complete miscible.
The binary solid-liquid diagram in Figure 1 shows the
stability of different phases as a function of
temperature and composition. This example (Figure
1) shows a case where the solid components are
partially miscible, α+β. α(s) represents a solid state
mixture predominantly composed of substance A,
with B present as an impurity, and β(s) represents the
opposite case where A is an impurity. When a
substance is dissolved in a liquid and the freezing
point of the liquid is lowered, this is called freezing
pint depression, a colligative property that depends on
the number of solute particles present in the solvent.
The shape of the phase boundaries between the (α +
liquid region) + (β + liquid region), the liquidus
curves, describes the freezing point depression for
this mixture. The equation of the liquidus curves can
be derived from the Clausius-Claperyon equation
pf3
pf4

Partial preview of the text

Download Phase Diagram of Naphthalene-Diphenylamine System: An Experimental Study and more Thesis Chemistry in PDF only on Docsity!

Solid-Liquid Phase Diagram

of Naphthalene-Diphenylamine Two-Component System

Michael Go, Nate Manaloto, Ronald Reyes* *Faculty, Ateneo de Manila University; email: ron_rxn24@yahoo.com Abstract. The experiment aims to be able to construct a phase diagram of Naphthalene-Diphenylamine two-component system at constant atmospheric pressure for thermal analysis. From the phase diagram, the eutectic composition (XE) and eutectic temperature (TE) are determined and are compared with the literature value. Commercial Naphthalene is used to undergo this test, and see if it is of the same caliber as the standard Naphthalene. Keywords. Naphthalene-Biphenylamine. Eutectic point. Newton’s Law of Cooling. Thermal Arrest. Thermal Break. Introduction. In investigating the heterogeneous equilibrium between solid and liquid phases of a two- component system, a phase diagram is constructed. In constructing phase diagrams, cooling curves forms the basis for “thermal analysis”. From the phase diagram, the eutectic composition (XE) and eutectic temperature (TE) are determined. Figure 1. A Phase Diagram for a two component system in which the solids are partially miscible and the liquids are complete miscible. The binary solid-liquid diagram in Figure 1 shows the stability of different phases as a function of temperature and composition. This example (Figure

  1. shows a case where the solid components are partially miscible, α+β. α(s) represents a solid state mixture predominantly composed of substance A, with B present as an impurity, and β(s) represents the opposite case where A is an impurity. When a substance is dissolved in a liquid and the freezing point of the liquid is lowered, this is called freezing pint depression, a colligative property that depends on the number of solute particles present in the solvent. The shape of the phase boundaries between the (α + liquid region) + (β + liquid region), the liquidus curves, describes the freezing point depression for this mixture. The equation of the liquidus curves can be derived from the Clausius-Claperyon equation

under the assumption that the solution behaves ideally: T(XA) = Tf.A. + ln(XA)RTFA^2 /dHA = TA-((1-XA) + (1-XA)^2 /2 + …) RTf.A^2 /dHA Tf.A is the freezing point of compound A, and is also shown in Figure 2. dHA is the heat of fusion for compound A and XA is the mole fraction of compound A. An analogous equation can be written for compound B. The two liquidus curves intersect at the eutectic point, C. In the absence of a phase change, the rate of change in temperature follows Newton’s Law of cooling. The Newton’s Law of cooling predicts that there is an exponential approach to the ambient temperature. A solid is formed because the rate of cooling is changed as part of the heat exchanged with the surroundings that contributes to the phase transition. During the freezing point of a pure substance, when the temperature remains constant, this is called thermal arrest. In a two-component system, as the temperature is lowered, one component begins to freeze while the other component still remains in the liquid state. In this freezing process, the liquid’s concentration mixture changes as more and more solid forms, and this consequently changes the freezing point. For this reason, the rate of cooling is not constant, but is different from the rate of cooling of the original liquid. This change in the rate of cooling is known as thermal break. When the liquid reaches a certain ratio of the two components, a thermal arrest is observed. This temperature and concentration point is also known as the eutectic point. Experimental. The binary system will be naphthalene-diphenylamine. Make two series of runs: a Naphthalene-rich series beginning with pure Naphthalene followed by successive additions of Diphenylamine to the previous run; and a Diphenylamine-rich series similarly prepared with the Naphthalene-rich series*. Heat the mixture in water bath until completely melted, and then, remove the water bath and measure the temperature periodically (e.g. every 15 seconds for the first 5 minutes, 30 seconds for the next five minutes, and every minute for the latter parts until the eutectic temperature is reached) until the system is essentially solid. Table 1. Approximate range of composition for the two-component Naphthalene-Diphenylamine mixture Approximate Range of Composition Pure A - Naphthalene: 10 g. Pure B - Diphenylamine: 10 g. Run B (g) Wt. % A Run A (g) Wt. % B 1A 0.0 100 1B 0.0 100 2A 1.5 87 2B 1.5 87 3A 2.0 74 3B 2.0 74 4A 2.5 63 4B 2.5 63 5A 3.0 51 5B 3.0 51 Results. Figure 2. The constructed phase diagram with the freezing points plotted, temperature (y-axis) and mole fraction of Naphthalene (x-axis). The best fitted curve is used and the eutectic point and temperature were determined. Eutectic composition (XE) = 0. Eutectic temperature (TE) = 21. Discussion: In the constructed phase diagram, a few changes were made. The best fitted curve was used in order to get the eutectic point. The experimental value

Figure 1. A Phase Diagram for a two component system in which the solids are partially miscible and the liquids are complete miscible. Figure 2. The constructed phase diagram with the freezing points plotted, temperature (y-axis) and mole fraction of Naphthalene (x-axis). The best fitted curve is used and the eutectic point and temperature were determined. Figure 3. A run of Diphenylamine with 3 grams of Naphthalene as impurity, the graph illustrates the thermal break and the thermal arrest.