Hi Mr David,

Can you please help me solve the qn below? I’ve been trying really long to figure it out already.

"2.8g of metal M reacts a metal oxide with 0.8g of oxygen to form MO. Metal M also reacts with oxygen to form a second oxide with oxygen in which the metal and oxygen present is in a ratio of 7:3. What is the formula of the metal oxide? "

A:MO2 , B: M2O , C:M2O3 , M3O2

Can someone pleaaase help me solve this qn!! I’ve been trying really long to figure it out already.


"2.8g of metal M reacts a metal oxide with 0.8g of oxygen to form MO. Metal M also reacts with oxygen to form a second oxide with oxygen in which the metal and oxygen present is in a ratio of 7:3. What is the formula of the metal oxide? "

A:MO2 , B: M2O , C:M2O3 , M3O2

Can someone pleaaase help me solve this qn!! I’ve been trying really long to figure it out already.


"2.8g of metal M reacts a metal oxide with 0.8g of oxygen to form MO. Metal M also reacts with oxygen to form a second oxide with oxygen in which the metal and oxygen present is in a ratio of 7:3. What is the formula of the metal oxide? "

A:MO2 , B: M2O , C:M2O3 , M3O2

I’ve been trying to figure this out but I still don’t understand.

Why is dx/dy proven to be 1/(dy/dx)? I know that dx/dy cannot be treated as a fraction because it simply isn’t a fraction. Please help,thanks so much!

Oh... I see. Okay,thanks so much.

HAHAHA. Yeah, qn 10 of chem tutorial?

Can you please help me to solve this question?


10cm^3 of a hydrocarbon C4Hy was allowed to react with an excess of oxygen at 150°c and 1atm. There was an expansion of 10cm^3 in volume. Deduce the value of y.

Is the "expansion" stated in comparison to the volume of the hydrocarbon AND excess oxygen or to the volume of hydrocarbon AND reacted oxygen?

I got accepted into Raffles and I’m in the Science stream.

I’m in a dilemma between taking H2 bio and H2 phys as well as H2 eng lit and H2 econs. I’m taking H2 chem and H2 math for the other two subjects. I do have more interest in bio then in phys but would the heavy content for bio be one to cause regret? The thing is, unlike most of my peers, I really have no idea what I want to do in life(it really irritates the hell out of me sometimes) and hence, I don’t really have anything to base my decisions on. Sigh. Therefore,I’d really like some advice over whether to choose phys or bio…and the same goes for econs and lit.
I was in the triple science stream in secondary school and I didn’t take lit as an o’lvl subject.
Oh and would anyone recommend one to take up the English Language and Linguistic Scholarship and KI? English has always been my strongest subject,if that helps.
I’d really really appreciate any help given! ((:

Thank you for all of your advices and for being so helpful. ((:

Hi,I received my o level results on thurs and I’m left with one day before I submit my JAE form. I’m deciding between raffles or hwa chong,having deliberating for a really long time whether or not I wld be able to fit in and manage. I’m from a neighbourhod schl but I’ve worked rlly hard for my o level results. The thing is, I live in bukit panjang which is in the west and hwa chong is definitely nearer and there’s a direct bus as well. I would,at most take 35mins to reach the schl. As for raffles,it would take me at least one hour. I’m clearly aware that distance is an important factor to be taken into consideration for a jc student. I rlly like the raffles campus though. What should I do? Would distance really affect everything?

Hi,I received my o level results on thurs and I’m left with one day before I submit my JAE form. I’m deciding between raffles or hwa chong,having deliberating for a really long time whether or not I wld be able to fit in and manage. I’m from a neighbourhod schl but I’ve worked rlly hard for my o level results. The thing is, I live in bukit panjang which is in the west and hwa chong is definitely nearer and there’s a direct bus as well. I would,at most take 35mins to reach the schl. As for raffles,it would take me at least one hour. I’m clearly aware that distance is an important factor to be taken into consideration for a jc student. I rlly like the raffles campus though. What should I do? Would distance really affect everything?