Chemistry- rates/orders of reaction
im just a bit baffed about all of this stuff. it's an easy enough concept to grasp and memorise, but when it comes to understanding things i get stuck, because i can never find the answers im looking for online. so i have a few questions about concepts im struggling to understand, if you guys dont mind answering them!
-what actually determines what order of reaction a reactant will be? i understand that 1st order means that as the concentration of [A] increases, the rate increases by the same factor, and so on with 2nd and 3rd order etc. but what is the actual chemistry behind it?
-sort of leading on from the last question, but what makes a reactant zero order? aside from the example of the reverse of the Haber process, which i understand to be zero order due to the need of a catalyst ( and so that reaction is dependant on the presence of the catalyst only). but what about a reaction like 2NO + H2 --> N2O + H2O, where the H2 is also zero order?it is definitely involved in the reaction, so shouldnt an increased concentration of H2 lead to more collisions, therefore a higher rate of reaction (according to GCSE)?
-why are all decomposition reactions 1st order? i keep reading that because there is one reactant involved, the reaction will be 1st order, but considering i dont actually know what makes something 1st and 2nd order, i dont really get that.
im very sorry if these questions actually have very simple answers and im wasting your time! but as you might be able to tell, i havent been left with a particularly great a level chem teacher and im being taught next to nothing
-what actually determines what order of reaction a reactant will be? i understand that 1st order means that as the concentration of [A] increases, the rate increases by the same factor, and so on with 2nd and 3rd order etc. but what is the actual chemistry behind it?
-sort of leading on from the last question, but what makes a reactant zero order? aside from the example of the reverse of the Haber process, which i understand to be zero order due to the need of a catalyst ( and so that reaction is dependant on the presence of the catalyst only). but what about a reaction like 2NO + H2 --> N2O + H2O, where the H2 is also zero order?it is definitely involved in the reaction, so shouldnt an increased concentration of H2 lead to more collisions, therefore a higher rate of reaction (according to GCSE)?
-why are all decomposition reactions 1st order? i keep reading that because there is one reactant involved, the reaction will be 1st order, but considering i dont actually know what makes something 1st and 2nd order, i dont really get that.
im very sorry if these questions actually have very simple answers and im wasting your time! but as you might be able to tell, i havent been left with a particularly great a level chem teacher and im being taught next to nothing
Original post by aeneas_son
im just a bit baffed about all of this stuff. it's an easy enough concept to grasp and memorise, but when it comes to understanding things i get stuck, because i can never find the answers im looking for online. so i have a few questions about concepts im struggling to understand, if you guys dont mind answering them!
-what actually determines what order of reaction a reactant will be? i understand that 1st order means that as the concentration of [A] increases, the rate increases by the same factor, and so on with 2nd and 3rd order etc. but what is the actual chemistry behind it?
-sort of leading on from the last question, but what makes a reactant zero order? aside from the example of the reverse of the Haber process, which i understand to be zero order due to the need of a catalyst ( and so that reaction is dependant on the presence of the catalyst only). but what about a reaction like 2NO + H2 --> N2O + H2O, where the H2 is also zero order?it is definitely involved in the reaction, so shouldnt an increased concentration of H2 lead to more collisions, therefore a higher rate of reaction (according to GCSE)?
-why are all decomposition reactions 1st order? i keep reading that because there is one reactant involved, the reaction will be 1st order, but considering i dont actually know what makes something 1st and 2nd order, i dont really get that.
im very sorry if these questions actually have very simple answers and im wasting your time! but as you might be able to tell, i havent been left with a particularly great a level chem teacher and im being taught next to nothing
-what actually determines what order of reaction a reactant will be? i understand that 1st order means that as the concentration of [A] increases, the rate increases by the same factor, and so on with 2nd and 3rd order etc. but what is the actual chemistry behind it?
-sort of leading on from the last question, but what makes a reactant zero order? aside from the example of the reverse of the Haber process, which i understand to be zero order due to the need of a catalyst ( and so that reaction is dependant on the presence of the catalyst only). but what about a reaction like 2NO + H2 --> N2O + H2O, where the H2 is also zero order?it is definitely involved in the reaction, so shouldnt an increased concentration of H2 lead to more collisions, therefore a higher rate of reaction (according to GCSE)?
-why are all decomposition reactions 1st order? i keep reading that because there is one reactant involved, the reaction will be 1st order, but considering i dont actually know what makes something 1st and 2nd order, i dont really get that.
im very sorry if these questions actually have very simple answers and im wasting your time! but as you might be able to tell, i havent been left with a particularly great a level chem teacher and im being taught next to nothing
Don't waste your time blaming your teacher! Look on the internet: WikiHow- 'How to determine order of reaction' It took me less than 10 minutes to find this. Just take responsibility for your own learning and you will be fine! And don't bother trying to memorise stuff that you don't understand; it does not work when you have to do new exam questions.
Original post by mgi
Don't waste your time blaming your teacher! Look on the internet: WikiHow- 'How to determine order of reaction' It took me less than 10 minutes to find this. Just take responsibility for your own learning and you will be fine! And don't bother trying to memorise stuff that you don't understand; it does not work when you have to do new exam questions.
i do understand how to calculate the order of reaction. like i said, im completely comfortable with the maths. but that doesnt mean im comfortable with just memorising a few concepts without understanding them, and the fact that i dont understand those concepts is why i asked the questions above. i have looked plenty on the internet, but all explanations to the questions i asked explain it whilst assuming i have some sort of prior knowledge (which i dont), and which is why i asked them here. but im sorry for wasting your time!
Original post by aeneas_son
i do understand how to calculate the order of reaction. like i said, im completely comfortable with the maths. but that doesnt mean im comfortable with just memorising a few concepts without understanding them, and the fact that i dont understand those concepts is why i asked the questions above. i have looked plenty on the internet, but all explanations to the questions i asked explain it whilst assuming i have some sort of prior knowledge (which i dont), and which is why i asked them here. but im sorry for wasting your time!
No. You are welcome. Maybe you could ask me more basic chemistry questions about what exact things you don't understand? Which exact bits of the Wikihow do you have a challenge with? And also say what you study style is like? ie how long do you spend studying and how you study?
Original post by mgi
No. You are welcome. Maybe you could ask me more basic chemistry questions about what exact things you don't understand? Which exact bits of the Wikihow do you have a challenge with? And also say what you study style is like? ie how long do you spend studying and how you study?
the most basic question i can think of is what first order, second order etc actually means chemically, not mathematically. like is a 2nd order reactant involved in the reaction twice (in different steps of reaction)? what property actually causes a chemical in a reaction to be 2nd or 1st order.
studying style and time i really couldnt give you an answer to haha. it varies a lot, but i pretty much study consistently with consistent breaks whenever my body needs me to have a break. if i take breaks based on a schedule i find it ruins my rhythm of work, and ive already got those structured study hours in sixth form. im not sure how i study either- pretty much collecting a lot of info from different sources which i understand, laying it out so i remember it, then formulating questions on aspects im unsure about then researching that to further my understanding. when i cant find answers i would ask my teacher, however this year i received the short end of the stick so that wasnt an option (did last year too, but you can get away with a bad teacher for 1 year of gcse chem). hence, i am here
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