摊手,秀一秀我们十一年级时候写的Lab Report的一部分~
Apparatus and Material
250ml beaker
10ml pipette
100ml volumetric flask
250ml Erlenmeyer flask
Electric scale
Scoopula
Wash bottle
Stand
Burette
White plastic disc
Goggles
Utility clamp
3g sodium hydroxide
10ml Vinegar sample A
10ml Vinegar sample B
Phenolphthalein indicator
Weighing paper
Procedure
1.Goggles were obtained and worn.
2.The weighing paper’s weight was zeroed by the electronic scale.
3.1.86 grams of sodium hydroxide was measured by the electronic scale.
4.The sodium hydroxide was washed down into a 100ml volumetric flask by wash bottle.
5.The 50ml burette was rinsed by water, and then rinsed by approximately 10ml of sodium hydroxide.
6.The 50ml burette was filled until the meniscus reached the 0.0ml mark.
7.The 50ml burette was attached to a stand by a utility clamp
8.The Erlenmeyer flask was rinsed.
9.10ml of vinegar sample A was transferred into a 250ml Erlenmeyer flask by a 10ml pipette.
10.2 drops of phenolphthalein indicator was added to vinegar sample A.
11.The Erlenmeyer flask was placed on a white plastic disc on the stand.
12.The initial burette reading for trial one vinegar sample A was recorded to the nearest 0.01ml.
13.The left hand was used to control the burette stopcock, and the right hand was used to swirl the Erlenmeyer flask continuously once titration had begun.
14.The stopcock was opened and then the base was allowed to drain into the Erlenmeyer flask. The contents of the flask were swirled.
15.The stopcock was closed when the light pink colour appears and stays for at least 20 seconds.
16.Record the final reading for trial one vinegar sample A.
17.The burette was not refilled, and steps 9-12 were repeated for the second trial of vinegar sample A.
18.Steps 13-15 were repeated, and then the final reading for trial two was recorded.
19.The burette was filled up to 0.0ml again by sodium hydroxide, and placed back to the stand.
20.Steps 9-18 were repeated, this time vinegar sample B was being used.