https://padlet.com/bgss/measurement_and_experimental_techniques en-us 2017-01-09 15:34:23 UTC 2025-10-24 09:03:26 UTC hello@padlet.com kuansiang1 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/146823695 Watch the video in this link about collection of gases.
https://www.youtube.com/watch?v=EOBRZxn4JIA
Do you have any questions you want to ask?]]> 2017-01-12 15:57:26 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/146823695 kuansiang1 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147220280 Watch the below videos about some of the  important Separation techniques that you need to know and post questions that you have after watching the videos.

Paper Chromatography
https://www.youtube.com/watch?v=PvHvx7k7UPU

Calculating Rf values

Simple distillation
https://www.youtube.com/watch?v=V5ep0-ojPGw
Crystallisation
https://www.youtube.com/watch?v=nztV4w0DtOo

]]> 2017-01-15 08:22:02 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147220280 kuansiang1 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147221867 Some help for your workbook worksheet 2
Section B : structured questions

Question 1c
Search"Calculate Rf value"

Question 2c
https://www.minichemistry.com/determining-if-a-substance-is-pure.html

Section C : Free Response Questions

Question 1
Search "Filtration" and "Crystallization" and understand these two process.  

Question 2
Search videos on "distillation" and "fractional distillation" and find out the difference between these two to answer this question

Search images on "heating curve of fractional distillation" to answer (di)

Search on "separating funnel". to answer part (e)



]]> 2017-01-15 09:13:26 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147221867 kuansiang1 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147225026 1) Make use of the Boolean Algebra AND and inverted commas
e.g  Google search engine will search for exact phrase of simple distillation and filtration if you type  "simple distillation" AND "filtration"  
2) Make use of the "video" tab of the search results to learn concepts more effectively.]]> 2017-01-15 10:26:11 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147225026 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147294860 If we use the over water method to collect the gas and the gas is denser than water what will happen to the gas ]]> 2017-01-16 07:40:06 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147294860 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147295177 If the gas is soluble in the water do we need to change the liquid used in the over water method ?
 
Teacher's response:
Can change the liquid to oil. Gases that not soluble in water are usually soluble in organic solvent such as oil.]]> 2017-01-16 07:42:13 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147295177 shameermsh27 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147342243 What if other gases are put into balloons will they be still able to float]]> 2017-01-16 12:21:49 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147342243 shameermsh27 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147342907 Off the 4 methods which is most common in daily lives

Teacher's response
These methods are used in chemistry lab.]]> 2017-01-16 12:26:33 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147342907 shameermsh27 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147343198 What is the difference between upward displacement and downward displacement?
How does the movement of gases vary?]]> 2017-01-16 12:28:09 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147343198 shameermsh27 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147343591 Why is the gas syringe method suitable for all gases?

Teacher's response : 
Depends on your usage of the gas collected, if you need your gas to be very pure, then gas syringe method is not suitable to collect the gas. But if you using it to measure the volume, then gas syringe method is suitable.]]> 2017-01-16 12:30:45 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147343591 shameermsh27 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147343861 Why are all gases less dense than water?

Teacher's response : Gas particles occupies more space than liquid water particles. Thus all gases are less dense than water.]]> 2017-01-16 12:32:45 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147343861 shameermsh27 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147344077 What method is used for sodium chloride and sulfur dioxide

Teacher's response : 
Sodium chloride is not a gas at room temperature. So not using any of the gas collection methods. Sulfur dioxide is denser than air. Use downward delivery method.]]> 2017-01-16 12:33:45 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147344077 shameermsh27 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147344275 Can all gases make the ballon float? Teacher's response : No]]> 2017-01-16 12:35:10 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147344275 shameermsh27 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147344351 Does the material of the ballon affect how Ling the ballon can float]]> 2017-01-16 12:35:40 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147344351 hongfeng634 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147831043 How do we seal the flask without air getting in? Will air getting in affect the results?

Teacher's response
Yes ]]> 2017-01-18 15:06:00 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147831043 hongfeng634 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147832583 Other then water, is there any other liquid that could replace water?]]> 2017-01-18 15:09:58 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147832583 hongfeng634 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147834162 Why is filter paper used in Paper Chromatography? Instead of Normal Paper

Teacher's response :  
Normal paper does not absorb the solvent as well as filter paper.]]> 2017-01-18 15:14:30 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147834162 hongfeng634 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147836167 Simple Distillation does not work when the boiling point of two substances is less then 25 degrees celsius. Because they do not get separated and purified completely, how so?( why 25 degree celsius?) ]]> 2017-01-18 15:19:50 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147836167 hongfeng634 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147837149 What is the maximum amount of any substances that can be gotten through Crystallisation?

Teachers : Depends on the amount of dissolved substances]]> 2017-01-18 15:22:36 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147837149 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147976618 Is water the only liquid that can be used?]]> 2017-01-19 00:21:29 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147976618 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147976646 Can we use other liquids such as alcohol?]]> 2017-01-19 00:21:51 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/147976646 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/148517957 Is crystalization able to be done at extremely high or low temperatures?

Teacher's response:
Crystallization occurs generally at normal room temperature or lower than that. I am not sure about extreme high temperature and low temperature.  ]]> 2017-01-21 15:25:32 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/148517957 kuansiang1 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/151707061 There is no gas that is denser than water]]> 2017-02-06 01:41:14 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/151707061 kuansiang1 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/151707086 You could use liquid such as oil for gases that are not soluble in oil.]]> 2017-02-06 01:41:31 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/151707086 kuansiang1 https://padlet.com/bgss/measurement_and_experimental_techniques/wish/151708199 25 degree celsius is a rough gauge. If the boiling points of the miscible  liquids are too close together,  there are complications due to evaporation of either liquids, your distillate would not be pure. ]]> 2017-02-06 01:53:47 UTC https://padlet.com/bgss/measurement_and_experimental_techniques/wish/151708199