Lower Secondary Science

[Vivian22]

Thank you very much Dr. Daniel :goodpost:

[Vivian22]

Hi, I need help with a few Chemistry questions


1) Which of the following shows the number f atoms present in 6 dm^3 of ethene at room temperature and 1 atmosphere?
A) 1.5 x 10^23
B) 3 x 10^23
C) 6 x 10^23
D) 9 x 10^23

2) In 10g of the following halogens, which has the most number of particles?
A) chlorine
B) bromine
C) fluorine
D) iodine

3) An organic compound P reacts with sodium oxide to give a compound with formula C3H5O2Na. WHich of the following is compound P?
A) ethanol
B) propanol
C) ethanoic acid
D) propanoic acid.

Thanks

[Dr.033430Daniel]

Vivian22:

Hi, I need help with a few Chemistry questions


2) In 10g of the following halogens, which has the most number of particles?
A) chlorine
B) bromine
C) fluorine
D) iodine

Thanks

C) Flourine. If you look at the periodic table of the elements you can see the atomic mass of each element. Flourine has the lowest atomic mass for any element on this list, so 10g will contain more particles.

[Dr.033430Daniel]

[quote="Vivian22"]Hi, I need help with a few Chemistry questions


1) Which of the following shows the number f atoms present in 6 dm^3 of ethene at room temperature and 1 atmosphere?
A) 1.5 x 10^23
B) 3 x 10^23
C) 6 x 10^23
D) 9 x 10^23


A.\tEthene has a molecular weight of 28 grams per mole. It has a density of 1.18 kg/m3.
6dm3 = 0.006m3. Multiply that by the density and you get 7.08 grams. Divide this by 28 and you have 0.25 moles. A mole is 6.02 X 10 ^23 atoms. 0.25 moles is 1.5 x 10^23 answer A.

[Chan09]

Are there any recommended sec1 or 2 science guide books that would be useful as I find it hard to know which ones to use as the sec schools vary as I am doing o levels in 2016? The ones I see are from MC or GLM though not sure if school notes are sufficient for lower sec? Tks

[Vivian22]

Thanks again Dr Daniel

[milkbun]

Chan09:

Are there any recommended sec1 or 2 science guide books that would be useful as I find it hard to know which ones to use as the sec schools vary as I am doing o levels in 2016? The ones I see are from MC or GLM though not sure if school notes are sufficient for lower sec? Tks

Do share with me if there's any good ones cos my boy going sec 1 next year.

Anyway, his tutor provides very good notes and materials...so dont really need to worry...but just being kaisu here...tt's why i'm a kaisu parent.

:evil:

[LarryG67]

For science, my son uses these book from popular by the ‘Education Publishing House’ publisher. Quite concise and clear.

[Bookshop]

eyktay:

FOR SECONDARY 1:

1) Without tuition, what are some recommended websites, guidebooks or enrichment materials to recommend?

2) If walking down the Tuition aisle.......any recommended centres or teachers?

MTIA!

Based on customer feedback, my recommendations are as follows:

1) Primary English:
- Casco

2) Primary and Secondary Maths
- Casco
- Shinglee

3) Primary Science
- Casco

4) Secondary Science
- GLM [For practice questions]
- Smashing Exams [For notes]

[Geraldinelim]

thanks for recommending…


I leave it to my tutor. They are the experts. They provide good notes and excellent practice Qs. In fact so close to my girls’ papers…