Ex 9

‫بسم ال الرحمن الرحيم‬ Name: ayedzahran Group: Day:

Experiment 9 "Stoichiometry of two chemical reaction" __________________________________________________________________ I. Observations and results: A. Reaction between HCl and NaOH: Table 1 ml 1 M HCl 5 10 15 20 25 30 35 40 45

ml 1 M NaOH 45 40 35 30 25 20 15 10 5

Temperature change 25-24=1 Cº 25-23.5=1.5 Cº 25.5-22.5=2 Cº 26-23=3 Cº 27-23=4 Cº 26-22.5=3.5 Cº 24-22=2 Cº 22.5-21.5=1 Cº 22-21.5=0.5 Cº

B. Reaction between H2SO4 and NaOH Table 2 ml 1 M H2SO4 5 10 15 20 25 30 35 40 45

ml 1 M NaOH 20 20 20 20 20 20 20 20 20

Temperature change Cº 30.5-23=7.5 Cº 10.5=33.5-23 Cº 9.5=33-23.5 Cº 9=32-23 Cº 8=31-23 Cº 7.5=30.5-23 Cº 6.5=29.5-23 Cº 6=29-23 Cº 5.5=28-22.5

III. Answer the following questions: 1. Based on your results above, in what molar ratio do: a. HCl and NaOH react: 1:1 b. H2SO4 and NaOH react: 1:2 2. Write balance equation for the reaction between:

a. HCl and NaOH: HCl + NaOH b. H2SO4 and NaOH: H2SO4 + 2NaOH

NaCl + H2O + ΔH Na2SO4 + 2H2O + ΔH

3. What is the difference between the forms of graph obtained in part A

and B of this experiment? Explain your answer. The difference between part A and B: A. The molar ratio in part A is 1:1, HCl:NaOH. and in B is 1:2

H2SO4:NaOH, we known that from the max change of heat, in that’s point in A was when the volume of the reactions is the same, and in B was when NaOH is 20 ml and H2SO4 is 10 ml. B. The change of temperature in B mar than A, because H2SO4 is

stronger than HCl. C. In A the curve start from 0 and end from 0, but in B start from

0 and goes to 0 after many times (when H2SO4 larger than NaOH many times),because in A the two reactions is change in volume so when the volume of any two reactions is 0 that’s mean no reaction so no change in temperature, in B the volume of NaOH is constant (20 ml) that’s mean the change of temperature goes to 0 (≈ 0) when the volume of H2SO4 more and more than NaOH, because the large volume and low heat. Not: For experiment number, For calculation number, For the solution of answers.