Glassware Terminology

Question 1

What is tolerance or accuracy?

Answer 1

limits of error, nearness to the true value.

Eg. 5.0ml +- 0.005mL

Question 2

What is precision or reproducibility?

Answer 2

ability to repeatedly produce the same value.

Eg. if 5mL pipette repeatedly delivers 5.1 mL.

Question 3

Most glassware is calibrated at which temperature?

Answer 3

20 degrees Celsius

Question 4

What happens if you take something out of the fridge and immediately measure 100ml in flask TD 20C?

Answer 4

It will end up giving you more liquid because it will expand once warm.

Question 5

TC and TD?

Answer 5

TC= to contain (to hold stated value)
TD= to deliver (delivering to another container)

Question 6

Is a Mohr and serological pipette calibrated to the tip?

Answer 6

Mohr- NO (comes in 0.1ml-25ml sizes)

Sero- YES

Question 7

Ultrasonic cleaners?

Answer 7

• used for cleaning small items

- high frequency vibrations cause soil to break free from walls.

Question 8

Semi-automatic pipette washers?

Answer 8

add water until full then siphoning action occurs, it drains faster than it fills.

Question 9

Glassware dishwasher has how many cycles and describe them.

Answer 9

six. 
1-pre-rinse
2- detergent
3,4,5- hot tap water removes all detergent
6- distilled water rinse

Question 10

Capacity

Answer 10

volume which glassware can hold or deliver. Eg. if a pipette is marked “1 in 1/100”, it has the capacity of 1mL and the graduations are in 0.01mL divisions.

Question 11

What happens when you measure a liquid that was hot?

Answer 11

Liquid expands when it is hot, if you measure a hot liquid that once it has cooled to room temp. then you will have a a higher concentration and less volume because it will contract.

Question 12

What happens when you measure a liquid that was cold?

Answer 12

Liquid contracts when it is cold which means that it will expand and you will have more liquid and it will be less concentrated.