SK015 EXPERIMENT 1 DETERMINATION OF THE FORMULA UNIT OF A COMPOUND
1. OBJECTIVES 2. INTRODUCTION 3. APPARATUS/ REAGENTS 5.RESULTS AND DATA 4. PROCEDURE 6. GUIDANCE FOR DISCUSSION 7. CONCLUSION
1.0 OBJECTIVES HOME 1. To Synthesis a Zinc Chloride Compound 2. To Determine the formula unit of Zinc Chloride
Main Properties of a compound 1. Can be known by its chemical composition : determining the elements present How to know the composition of unknown compound? 1. By using quantitative & qualitative analysis. 2. Once the composition of the compound is known, its formula unit can be determined. HOME 2.0 INTRODUCTION
Quantitative: Determination of the absolute or relative abundance (often expressed as a concentration of one, several or all particular subtance (s) present in a sample. Qualitative: Seek information about the identity or form of substance present HOME What is the meaning of..
1:PREPARE Simple Compound: Zinc and Chloride Mass Of Zinc Mass Of Chlorine
3.0 APPARATUS 1 3 2 4 5 6 7
CHEMICAL REAGENTS: ONLY 2 AND 1 2. HOME
Weigh the Crucible and Record the Exact Mass Crucible 1 Place: 0.25g Of Zinc powder into crucible Next 2 4.0 PROCEDURES Task 1: Mass of empty crucible
Precaution 1: NEXT STEP : 1.CARRY OUT IN A FUME CUPBOARD 2.DO NOT WORK NEAR A FIRE SOURCE BECAUSE WET H2 GAS CAN CAUSE EXPLOSIONS
Weigh the crucible with the zinc(0.25g) and determine the exact MASS of Zinc 2 Crucible+ Zinc (0.25g) Task 2: Mass of crucible + Zinc powder
Add 10mL of 6M HCl and stir the contents gently using glass rod. Task 3: Observe the Hydrogen gas will be released 3. Crucible + Zinc= stir 6M HCl H 2 gas is released Crucible+ Zinc = Reactions Next
IF ZINC POWDER DOES NOT DISSOLVED: Continue adding 5 mL 6M HCl until all Zinc is dissolved. The amount of acid must not exceed 20mL. 4. Crucible + Zinc 6M HCl 5 mL
5. Crucible + Zinc+HCl -Then: Heat slowly so that the content does not splatter during heating process. -Heat until compound become: COMPLETELY DRY! BE CAREFUL NOT MELTING PRECAUTION: RUN IN FUME CUPBOARD!! Hot plate Place on
Crucible +Zinc+HCl Hot Compound 6. Cool to Room Temperature Weigh on Task 4: Take the Mass of Crucible+Zinc+HCl (first heating mass: A gram)
7. Crucible +Zinc+HCl Reheat the crucible NEXT Cool to Room Temperature N E X T Crucible +Zinc+HCl Weigh it again Task 5: Mass Second heating:(B gram)
Repeat Step 8( shown in diagram) until the Difference in mass does not exceed 0.02 gram 8. Task 6: Mass third heating (C gram) HOME Crucible + Zinc+HCl
3. Calculate the FORMULA UNIT of Zinc Chloride 2. Calculate the Mass of Chloride in the Zinc Chloride 1. Determine the Mass of Zinc Chloride from the final Weight of the sample HOME TASKS
MASS (gram ) 1. Mass of crucible X 2. Mass of crucible& Zinc Powder Y 3. Mass of Zinc Powder Y- X= Z 5.0 RESULTS/DATA
MASS CRUCIBLE& ZINC CHLORIDE (gram ) 1. First heating A 2. Second heating B 3. Third heating C
MASS OF ZINC CHLORIDE MASS OF CHLORINE FORMULA FORMULA (C – X) gram = ( C-X-Z) gram =
CALCULATION OF THE FORMULA UNIT HOME Zn Cl Mass/g z c-x-z No.of mol z c-x-z 65 g mol-1 35.5 g mol-1 a b Simplest ratio a b a a Formula Unit
DISCUSSION 1. Zinc chloride can be synthesize by ………….. 2. Discuss the result obtain from experiment and compare to theoretical value. 3. The equation for this experiment is: 4. The contents cannot be weighed because …………… 5. The crucible must be covered during cooling process because ………………..
DISCUSSION 6. Error / limitation of this experiment : i. Zinc powder did not react fully. ii. .. iii… 7. Precaution step in this experiment : i. Hydrochloric acid must be added slowly to avoid vigorous formation of bubbles. ii. …. iii. ……
7.0 CONCLUSION HOME 1. The zinc chloride compound can be synthesize by.. 2. The formula unit of zinc chloride is…..