Date: 19 November 2014
Course and Section Number: SCIN 131
Lesson 2 Lab: Weighing on an Analytical Balance & Distillation
Begin by viewing the following Thinkwell video
15.1.8 CIA Demonstration: Weighing on an Analytical Balance
After you watch the above video, answer the questions below in sufficient detail:
(a) (2 pts) What are the features of an electronic balance? Include all of those discussed in the video.
Answer: Electronic balance features including electronic read-out and the tare. Electonic balance can measure mass to the precision of 0.0001. Electonic balance has the tare feature which resets a balance to zero in order to get the weight of the sample, and not the container of the sample. It has enclosed glass to contain the substance being measure (Thinkwell, 2012).
(b) (1 pts) What does “tare” mean? What is the importance of the ability to 'tare ' when taking the mass of your sample? Be specific.
Answer: The tare is used when restarting the weight to 0 hence, which lets you weigh by differences. The tare is significant since it helps to get the weight of the sample only not the weight of the sample and the container (Thinkwell, 2012).
(c) (2 pts) What is the difference between weigh boats and weigh paper, and in what circumstances should you use each? Be specific and detailed in your answer.
Answer: The weigh boats are containers used to stop reagents from contacting the balance area. Weigh boats which are called filter paper can be utilized as transporting vessel of the chemical to be measured. Filter papers are classified as low-cost version of the weigh boats. The material makeup of weigh boats or filter papers is polypropylene, a plastic that does not adsorb water (Thinkwell, 2012).
(d) (2 pts) According to the lab video, what is the difference in how you weigh smaller amounts vs. larger amounts, and what is the role of the scoopula in this? Explain in detail.
Answer: When weighing small amounts a clean
References: SCIN131 Introduction to Chemistry Lab, November 2014, Section K001. (n.d.). Retrieved November 19, 2014, from http://my.thinkwell.com/students/index.cfm