Q&A - PSLE Science

[Drdj]

Dear Dharma,


Thanks for your explanation. However, since air can be compressed, doesn't it mean 250 cm3 of air can fit into the flask volume of 200 cm3?
Or does it mean that no matter how much air there is, the flask volume is limited??

Dharma:

Drdj:

Dear tianzhu and dharma,

Thanks so much !! Appreciate your detailed explanations !!
Have scanned some further queries from various sources - hope you can help me with them - apologies for the many attachments, as I'm not sure how to do it all in 1 !!
Thanks again

http://www.postimage.org/image.php?v=PqmEHfJ

Air will compress to occupy the max. space in the jar (200cm3)

[Drdj]

Dear Dharma,


My apologies...the question part (c) should read \"Explain the difference between in the results from the two test-tubes\". Thanks.

Dharma:

Drdj:

Dear tianzhu and dharma,

Thanks so much !! Appreciate your detailed explanations !!
Have scanned some further queries from various sources - hope you can help me with them - apologies for the many attachments, as I'm not sure how to do it all in 1 !!
Thanks again

http://www.postimage.org/image.php?v=PqmEJKS

Q46
a) To find out how different temperatures of water in which the test tube containing yeast with sugar solution is immersed affect the amount of CO2 produced by the yeast.

b) 60 degrees celcius.

c) Sorry, I cant read the Qn

[Drdj]

Dear Dharma,


Thanks...for the 2nd question on the right, is it practically possible to push the plunger in, though air can be compressed? If the syringe is upright, that's perfectly fine.

Dharma:

Drdj:

Dear tianzhu and dharma,

Thanks so much !! Appreciate your detailed explanations !!
Have scanned some further queries from various sources - hope you can help me with them - apologies for the many attachments, as I'm not sure how to do it all in 1 !!
Thanks again

http://www.postimage.org/image.php?v=PqmEHfJ

Air will compress to occupy the max. space in the jar (200cm3)

[Dharma]

Drdj:

Dear Dharma,


Thanks...for the 2nd question on the right, is it practically possible to push the plunger in, though air can be compressed? If the syringe is upright, that's perfectly fine.

Dharma:

[quote=\"Drdj\"]Dear tianzhu and dharma,

Thanks so much !! Appreciate your detailed explanations !!
Have scanned some further queries from various sources - hope you can help me with them - apologies for the many attachments, as I'm not sure how to do it all in 1 !!
Thanks again

http://www.postimage.org/image.php?v=PqmEHfJ

Yes

Air will compress to occupy the max. space in the jar (200cm3)

[/quote]

[Drdj]

Dear Tianzhu


I'll try to enlarge them and put the sources in - some are from P6 past year papers, some from P4 assessment books - neither a parent or student, just looking for some help

tianzhu:

Hi Drdj

Could you help to provide the sources of your questions eg ACS P6 Sci Q35 SA2 2008?

It appears to me that the questions are from different levels? Just curious, are you a parent or student?

The scanned image may be slightly blurred and small and it may helpful to refer to the originals from http://www.wendykoh.com. Otherwise, it's very taxing for an old man like me to read.

[tianzhu]

Drdj:

neither a parent or student, just looking for some help

Looks like precious time should be channelled elsewhere, I see no reason why answers are needed when you are not a parent or a student.

But you must have some identity, right.It's very unlikely that you're a teacher.But if you are a private tutor, we take consolation that Dharma and my answers are of decently good standards to be of some use to you as you've requested for them.

Best wishes

[joconde]

Can someone help clarify this Q from my son’s P5 practice paper :


Which of the following statements about cells are true ?

A : All cells are the building blocks of life.
B : Cells cannot be seen by the naked eye.
C : Living things can be made of one cell or many cells
D : All cells are made up of a nucleus, cell membrane and cell wall.

1. A and B only
2. C and D only
3. A, B and C only
4. A, B, C and D

The answer provided by teacher is 2 (unless my son copied the wrong answer).

Why is D true ? Textbook says only plant cells have cell wall. My answer is A and C but this is not in the options.

[turquoise]

joconde:

Can someone help clarify this Q from my son's P5 practice paper :


Which of the following statements about cells are true ?

A : All cells are the building blocks of life.
B : Cells cannot be seen by the naked eye.
C : Living things can be made of one cell or many cells
D : All cells are made up of a nucleus, cell membrane and cell wall.

1. A and B only
2. C and D only
3. A, B and C only
4. A, B, C and D

The answer provided by teacher is 2 (unless my son copied the wrong answer).

Why is D true ? Textbook says only plant cells have cell wall. My answer is A and C but this is not in the options.

D is definitely false. Only plant cells have cell walls and red blood cells have no nucleus.

A & C are true.

I'm not sure about B but my daughter says cells cannot be seen by a naked eye so in her opinion, the correct answer is 3.

[joconde]

turquoise:

joconde:

Which of the following statements about cells are true ?

A : All cells are the building blocks of life.
B : Cells cannot be seen by the naked eye.
C : Living things can be made of one cell or many cells
D : All cells are made up of a nucleus, cell membrane and cell wall.

D is definitely false. Only plant cells have cell walls and red blood cells have no nucleus.

A & C are true.

I'm not sure about B but my daughter says cells cannot be seen by a naked eye so in her opinion, the correct answer is 3.

I just googled and found this : \"The Yoke of an egg is a single cell. That can easyly be seen by the naked eye\".
The sci guide book i bought states this : Most cells can be seen by naked eye.

I take that as implying that there are actually some cells that CAN be seen by naked eye.

So I guess there was probably error in this question.

[turquoise]

joconde:

I just googled and found this : \"The Yoke of an egg is a single cell. That can easyly be seen by the naked eye\".

The sci guide book i bought states this : Most cells can be seen by naked eye.

I take that as implying that there are actually some cells that CAN be seen by naked eye.

So I guess there was probably error in this question.

Probably.