CHEMISTRY PRATICAL WORK

CHEMISTRY

PRATICAL

WORK

MEMBER OF GROUP:

·       ASFARUR RIDLWAN                (06)

·       ASIH DIANI P.                                (07)

·       DHINAR PUTRIE M,               (08)

·       FAHMI ANDRIYANTO             (09)

SMA NEGERI 1 REMBANG

TAHUN AJARAN 2011/2012

CHEMISTRY REPORT

DETERMINING LEVEL OF REACTION

A.      THEORY

Reaction rates is influenced by the concentration of reactant. For reaction between A and B in the homogeny system, the relationship between reactant rates and concentration represented as:

Reactant rates = k [A]^m [B]ⁿ

“m”  is called as reaction order with respect to A, and “n” is called as reaction order with respect to B, (m+n) is total reaction order. In this experiment, will be determined the level of reaction with respect to reaction of :

Na₂S₂O_3(aq) + 2HCl_(aq) =>₂NaCl_(aq) + SO_2(g) + S_(s) + H₂O_(l)

B.      EQUIPMENT and MATERIALS :

EQUIPMENTS AND MATERIALS	SIZE/UNIT	TOTAL
Chemistry glass	100ml	2
Mesure glass	25ml	2
Stopwatch	-	1
HCl solution	2M	75ml
NA2S2O3 solution	0,2 M	125ml

C.      WORKING STEPS :

a.      Make a cross on a piece of white paper

b.      Put 10ml 2M HCl solution into the beaker and place the beaker on a cross.

c.       Add 20ml solution of 0.2 M N₂S₂O₃ and record the time since the addition to the cross no longer visible from above the solution.

d.      Repeat the experiment by using a diluted solution of N₂S₂O₃ first with water as in Table I.

e.      Repeat the experiment by using a diluted solution of HCl with water first observation in Table II.

D.     THE RESULT OF OBSERVATION

TABLE I

Volume HCL 2M	Volume (mL)			Molaritas N2S2O3	Time (s)
	N2S2O3 0,2 M	Water	Total Volume
10	20	0	30	0,2	60
10	15	5	30	0,15	90
10	10	10	30	0,1	120
10	5	15	30	0,05	380

Note :molaritasN₂S₂O_{3 =}

Ex : M2 = = 0,15

            TABLE II

Volume N2S2O3 0,2M	Volume (mL)			MolaritasHCl	Time (s)
	HCl2 M	Water	Total Volume
20	10	0	30	2	50
20	7,5	2,5	30	1,5	55
20	5	5	30	1	100

Note :molaritas N₂S₂O_{3 =}

Ex : M2 = = 0,15

F.       TASK

a.      Make a graphic concerning to Na₂S₂O₃!

b.      Make a graphic concerning to HCl!

G.     QUESTION

a.      In the experiments the reaction rate is measured based on what?

b.      Why is the total volume of the solution created equal?

c.        Why does the graph editor described as   ?

d.       Determine the level of reaction to Na₂S₂O₃ and to HCl!

e.       How the formula rate of reaction?

H.     ANSWER

a.      Concentration

b.      Because volume has to control the concentration and as bound variable.

c.       Because reactant rates  are explaining reduces  the sum of reactant substances each time and increases the sum of reactant substances each time. And time are reversely with the reactant rates.

d.      The level reaction of Na₂S₂O₃

 = 2                        = 2

2^X                     =          2

X            =          1

                  The level reaction of HCl

 = 2                     = 2

2^X                     =          2

X            =          1

      The total level reaction is 1 + 1 = 2

e.      V = k .[Na₂S₂O₃] . [HCl]

Conclusion : volume not influences of the reactant rates