Q&A - P5 Science

[HAPPYH]

cftan:

Thank you, dioprem. Will clarify with teacher again.

Hi, did you check with the teacher? TIA

[hterbin]

MOE is moving its focus to application based questions more often than questions where answers can mostly be memorised. This serves at more effectively accessing how much does a student understand instead of how much has the student memorised

[guchengyouzi]

Hi Dioprem,

What substances do you have in mind?

[guchengyouzi]

There is a good web site explaining melting and boiling points

http://anhourofchemaday.wordpress.com/? ... nt&submit=

[dioprem]

guchengyouzi:

Hi Dioprem,

What substances do you have in mind?

Do you mean the exceptions where the substances actually have freezing and melting points?

One substance that I know of is agar. Its melts at 85 degrees and solidifies from 31 degrees to 40 degrees. (All temperatures in Celsius.)

[guchengyouzi]

Thanks.

Interesting fact indeed.
This world is full of stranger things than you can imagine.

[susan88]

Please help to answer the following, thanks.


Extracted from 2012 ACS P5 SA1, Q27:
.
Jerome poured 50g of salt into a container of 100 ml of water.
a) What will happen to the water level in the container? Why?
b) What will happen to water level in the container after Jerome stirs the water until all the salt is completely dissolved? Why?

[guchengyouzi]

susan88:

Please help to answer the following, thanks.


Extracted from 2012 ACS P5 SA1, Q27:
.
Jerome poured 50g of salt into a container of 100 ml of water.
a) What will happen to the water level in the container? Why?
b) What will happen to water level in the container after Jerome stirs the water until all the salt is completely dissolved? Why?

a)Water level increases because salt is solid and occupies space.
b)Water level decreases but not back to the original position because the salt is not solid anymore but has turned into solution which occupies less space.

[Hougangdaddy]

Shouldn’t the nucleus of sperm be label and name as it also contributes to the baby blood group?

[Hougangdaddy]

Include picture for my question above. http://i62.tinypic.com/1zg3o12.png\">