{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

SURFACE TENSION BY THE RING METHOD

# SURFACE TENSION BY THE RING METHOD - T(c F(mN St(mN/m 20.5...

This preview shows pages 1–2. Sign up to view the full content.

SURFACE TENSION BY THE RING METHOD * Objective: 1. Measuring the surface tension (St) for Ethylene Glycol. 2. Determining Temperature Coefficient (Tc). 3. Determining the Total Surface Energy per unit area (Ua). * Theory: Intermolecular forces in liquids are very large not like those of the gases. So, at the liquid gas phase there exists a net force that points to the liquid phase. * Experiment: Refer to the book pages 81-86 Data: (GLYCE ROL, Dia = 1.88cm): F(mN) T(C) T(K) F(mN) T(C) T(K) 8.1 22.5 295.65 7.1 23 296.15 8.1 34 307.15 6.97 33 306.15 8.1 44 317.15 6.91 43 316.15 8 54 327.15 6.65 53 326.15 8 63.5 336.65 6.8 63 336.15 7.8 73.5 346.65 * Calculations:- * for GLYCEROL , r = 0.94cm * Using Formula 4: St = F / (4)(3.14)(r) -------------- 4 Values of Surface tension (St) : At 22.5 C : (8.1/1000) / (4)(3.14)(0.94/100) = 0.0686 N The rest of the values are tabulated as follows:

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: T (c) F (mN) St (mN/m) 20.5 6.12 25.9 35.0 6.08 25.7 45.5 6.05 25.6 54.5 5.97 25.3 64.8 5.80 24.6 74.0 5.68 24.1 y = -26.121x + 707.3 10 20 30 40 50 60 70 80 90 24 24.5 25 25.5 26 St Vs T From the graph equation: • The slope = dSt / dT = -26.121 • Ua = St – T.dSt / dT at 20.5 C Ua = 25.9 – (25).(-26.121) = 678.9 J/m • Temperature Coefficient Tc is given by Formula (6): Tc = St . (V m ) 2/3 = 1.9 X 10-7 J/K The nearly constant value = 2.1 X 10-7 J/K The difference = (1.9 X 10-7- 2.1 X 10-7 ) / 1.9 X 10-7 = 10.5 % This percentage of error could have occurred due to non-perfect performance of the experiment. * References: “PHYWE, University Laboratory Experiments CHEMISTRY”, P 3.2.4....
View Full Document

{[ snackBarMessage ]}

### Page1 / 2

SURFACE TENSION BY THE RING METHOD - T(c F(mN St(mN/m 20.5...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online