Or REGISTER
Free Chemistry Help
I provide Free Chemistry Help upto High School Level. Just place your questions at the Free Chemistry Help Forum and they will be answered in no time.
Chemistry Quizzes
 I provide Practice questions in Chemistry to the students on this website. Detailed quizzes with answers have been compiled for all the courses offered here. For Chemistry Quizzes, please click here.
Useful Resources

Important Chemical Reactions

Displacement Reactions and Net Ionic Reactions
What My Students Have to Say

You have made Chemistry so simple for my daughter. She says you are even better than her professor and that her classmates would like to have you as her professor.

Meera, California(parent)

I have gained immense confidence after studying with the tutors on this website. I recommend the tutors here to everyone who needs online tutoring and homework help.

Sarah Hamilton(Math)

My exams had gone off so well after my sessions for MCAT exams with you. I have thoroughly understood Aromatic Reactions, Alkenes and Alkynes after studying with you. Thank you so much. You are the best Chemistry Tutor I have ever had.

Yashika Patel, Boston(MCAT )

You are the best tutor that I have come across in my life. Keep up the good work.

Nick(MCAT)

Dear Uma, We want to thank you for the all hard work you did teaching Felix chemistry: Thanks to your dedicated tutoring he was able to score 760 on his Chemistry SAT test . We are very happy with the test results.

Alex and Katrina Glozman (parents of SAT/AP/general chemistry)

Hi Uma
I got my sat score today. I received a 760 for chemistry. Thank you very much for all your teachings.Under your guidance I will be successful in chemistry..

Felix(SAT Chemistry)

My wife and I will like to thank you for helping our son do so well at AP Chemistry. Although he got a 4, given where you picked him up and the total lack of teaching in his school, the exam outcome was a realistic one.
Mrs. Sharma. my son holds you in very high regard. He describes you as "One of the best teacher in the World " and he says so with a lot of conviction.
As parents we are grateful to you for helping him change his attitude to Chemistry from total fear and intimidation to love for the subject.

Mr P Maitra(Father of AP chemistry student)

Wanted to let you know that Mallika got a 5 on her AP Chemistry exam. Thank you for your efforts.

Radhika Madhusudan mother of AP student

Hello Uma, I just want to let you know that I got accepted to Midwestern University- Chicago College of Pharmacy (my preference) and I also received an invitation to interview at University of Illinois at Chicago College of Pharmacy as well! Both of these schools are the best in my area. I am beyond excited and overjoyed. Of course, it would not have been possible without your assistance and support in organic chemistry. My professors thought that I should pursue advanced organic chemistry or even PhD's- they did not know I worked with a great tutor by my side and that it had made all the difference for me to have met you. My success in my organic chemistry class spilled over to other science classes that I took. I plan to continue working hard and perhaps, very soon, I will need another session with you! Thank you very much again! Sincerely, Cat

Catphuong Nguyen(pharmacy student)

Dear Dr. Sharma, I want you to know that I see you as a mentor. So far, in my life, it has been my mentors who have really helped me, guided me, and I know will mold me even beyond the scope of my career. I will always remember to thank you for all you do. Thank you for all of your help and guidance, Dr. Sharma. Hope you feel better and I will get Sitopladi and Honey :) Kindest Regards, Vinay Sehgal

Vinay Sehgal (organic chemistry student)

Hello Uma, Thank you for your session this morning. My daughter said it was very informative and she learnt well. She said she liked the fact that you asked her questions. Please make sure she understands her basics well, even if it takes more of your time. I have bought a package for 5 hours. As discussed this morning, please schedule the lesson for 8:00 -10:00 am EST tomorrow 3/5. Thank you again for your time and efforts. Vidya

Vidya (mother of Deepika organic chemistry student)

I got my scores-in general chemistry my correct answers were 26 out of 30 questions so my DAT score is 20 out of 30. in organic chem my correct answers were 23 out of 30 questions so my DAT score is 19 out of 30. my average DAT score is 19 out of 30...not bad. we have to see what is the cut off of new york university. it shoud be around 18 or 19 or 20..according to the office people in the university. will come to know in 2013 spring thanks to you for everything..Icouldn't have scored even this much without your help. The overall exam was not that easy..there were some pretty hard questions.specially the PAT section was quite hard when I travel to india this december I will get all the DAT books for you. barrons,kaplan,dat destroyer. thanks again ,will talk when u are free. I was called for interview. will get the result on 3 weeks

Jaspreet (DAT student)

hello uma ji, The cut off of DAT at the new york university has gone down to 17. i have a score of 19 . still waiting for my result. my application got submitted after the deadline due to some reasons. but hoping for the best. hope you are still rocking at ur lectures and wishing you luck as always

Jaspreet(DAT student)

Hi I am Shah here.I am taking regular tutoring from chemtopper for organic I from uma sharma(tutor).Today I appeared in my final examination and my professor just scanned my answers and told me to get enroll in organic II .This is never heard in USA that a professor asking a student to join a course like this.I think this is something awesome in a student's career .I am really thankful to chemtopper and specially to Uma Sharma (my preferred tutor) who really helped me a lot during my examination time.She helped me understanding organic chemistry in much simpler way by her unique way of teaching.I would like to continue with her as my preferred tutor for organic chemistry II.

Shah (2009)(organic chemistry student)

I had been a novice at Chemistry when I joined Organic Chemistry-I. In my first exam I had got ‘F’ grade and was on the verge of leaving Organic Chemistry when I found you. You have made Organic Chemistry so simple for me. I am now the topper of my class having scored 100% in my exams !!!

Kim Dewitt(organic chemistry student)

In my DAT I was in the top 93 percentile of the US for that section, which means I scored higher than 93% of all test takers. it was all thanks to you Can't tell you how much you helped.

Neha Garge(DAT student)

Hello I would like to thank a very articulate tutor Miss Uma Sharma specifically for helping me with Organic chemistry. Her knowledge of subject is amazing. The way she deals with the topics reveals her deep understanding of the subject. Her encouragement to delve deeper into the subject keeps me flocking into her session. She helps me understand my assignments well so that i am able to work independently. She was never lost for words when questioned, and i always had answers. Miss Uma Sharma is indeed an asset as a tutor. I praise her dedication and genuine love for her profession that was evident in the way she taught.

SHAH Colorado, USA(organic chemistry)

Ms.Uma was very helpful. The active teaching when she asks the student gives the student practice and ensures their understanding which I found helpful.

Neije(Moitreyee)IB student

Uma, Qian transfer from 11th grade to 12th grade on chemistry subject, she was assessed 2 days ago. When I got the news, I want to thank you again for being a very good chem teacher.

Helen( Quian's mother)

I was so happy when I heard my daughter passed AP Bio & Chem both with 4s. Her effort has paid off. I credit Chemtopper for tutoring her. My daughter's school wasn't able to offer AP classes, and I wasn't able to find tutors who taught AP in English in China, so I turned to online AP courses, and I found Chemtopper. Chemtopper's team is wonderful; both our Bio and Chem tutors are PhDs and very experienced tutors. We went through all the content in 3 months and passed the exams with satisfactory results.

Helen Feng(Qian's mother)

just to let you know that Aarti got an offer for a Pharmacy course in London ,King's colleges.She is very excited... she got all the offers from UK thanks for all yr help you gave to aarti she feels comfortable with chemistry

Renuka Patel(mother)

Really good. Tutor was well prepared and explained concepts by using different examples. The sessions are saved so they can be revised afterwards as well. ** HIGHLY RECOMMENDED **

Jamal Ahmed IB chem student

HI Uma ji, I got admission into DDS programme at NYU. Thanks a ton for helping me through and motivating me all the time I wish good luck to you . Your teaching will help make students with a strong foundation God bless you

Jaspreet (DAT student)

Dear Dr. Sharma, Would like to finish chapter 3 in tomorrow's session. I make sure to review notes after our sessions and then go back to re-read the Kaplan book. You are absolutely right: without a complete understanding of the topic, it will be very difficult to grasp the material. Thank you for helping me understand the material so thoroughly.

Vinay Sehgal (MCAT student ))

Dear Uma, My wife and I want to thank you once again for the excellent teaching that you provide to our younger son Thomas. Thanks to your dedicated teaching he, while still in 10th grade, was able to score a 5 in AP Chemistry. You helped him build a solid foundation in inorganic chemistry, and now continue to teach him organic chemistry. He is happy to be your student and we are happy you are his teacher. Sincerely, Ekaterina and Alex Glozman

Alex and Katrina Glozman (parents)

Hi Dr. Sharma, I'm reviewing Orgo Part 2. Everything you taught me is coming back very easily. Once again, thank you! Orgo is 25% of the Biological Sciences section and every point counts. Chemistry is 50% of the Physical Science section so I am making sure to keep up in that area too. Hope you have a safe trip. See you soon. Kind Regards, Vinay Sehgal

Vinay Sehgal (MCAT student ))

A great tutor who enjoys chemistry as well as teaching it. Her teaching style is very understandable and easy. Neither have i had such a good chemistry tutor or have I understood chemistry as much as i did before I started classes with Uma. Couldn't ask for a better chemistry tutor!

Sai Muttavarapu-2013

Great job teaching Organic Chemistry specifically mechanisms of reactions. Thank you.

Felix

After the session I finally understood resonance structures of organic compounds. This is a high yield topic on the MCAT. I wish my college professor could teach as well as Uma.

Felix

I'm in the IB program, and having these online sessions to review for my exams are perfect! Thanks a lot!

Dusan

Really good. Tutor was well prepared and explained concepts by using different examples. The sessions are saved so they can be revised afterwards as well. ** HIGHLY RECOMMENDED **

Jamal Ahmed

It's great that you are so patient in explaining things multiple times and giving extra examples to work out to make sure that I understand the points. Thanks for all your help!

Sunitha

Great session, I really like how you're challenged on your knowledge, it keeps you on your toes while learning - thanks!!

Trevor

very good lecture. mrs. uma know where to hit the chord

Jim

the lecture was awesome. never thought i could solve organic chemistry with ease . it has been made possible under the guidance mrs. uma sharma..a wonderful teacher who has a very fine understanding of the needs of her students .

Jaspreet

I can tell you, the help is so valuable. I was ranging from 74-82%, everything is 90+ now waiting for the chem marks to be posted from last week. amazing tutoring in chemistry

Trevor Poole


LiveZilla Live Help
Important Chemical Reactions

(1) Sulphur Sulphuric acid

S+O2SO2

2SO2+O2 2SO3

SO3+ H2O H2SO4

(2) Calcium Calcium Hydroxide

2Ca +O2 2CaO

CaO+H2OCa(OH)2

(3) Nitrogen Nitric Acid (HNO3) + Nitrous Acid (HNO2)

N2+O2 2NO

2NO +O 22NO2

2NO2+H2O HNO2+HNO3

(4) Nitrogen Ammonium Hydroxide

N2 NH4OH

N2+3H2 2NH3

NH3+H2ONH4OH

(5)Sodium Sodium Hydroxide

Na NaOH

2Na + 2H2O 2NaOH +H2

or 4Na +O2 2Na2O

Na2O+H2O 2 NaOH

(6) Iron Ferric Hydroxide

Fe Fe(OH) 3

2Fe+3Cl 2 2FeCl 3

FeCl3+3H2OFe(OH)3+ 3HCl

(7) Iron Ferrous Hydroxide

Fe + 2HCl(cold and dilute) FeCl2

FeCl2+2H2OFe(OH)2+ 2HCl

(8) Copper Copper Sulfate

Cu + Conc H2SO4 CuSO4 + 2H2O + SO2

Chemical reaction to distinguish between Mixture and Comound

Fe +S+2HCl FeCl2+S+H2(blue flame pop sound)

FeS+2HClFeCl2 +H2S( rotten smell gas )

Important reactions for the preparation of Oxygen (O2)

Decomposition reactions

Decomposition of red Mercuric oxide

2HgO 2Hg+O2

Decomposition of hydrogen peroxide

2H2O2 H2+O2

Decomposition of potassium chlorate

2KClO3 2KCl +3O2

Decomposition of silver(I) oxide

2Ag 2O 4Ag+O2

Decomposition of lead oxide

2Pb 3O4 6PbO 2

Red Litharge

2PbO2 2PbO+O 2

Combustion reactions

CxH2y + (x+y/2)O2xCO2+yH2O

(easy way of balancing a combustion reaction of hydrocarbons )

CH4 +2O2 CO2 +2H2O

methane

C2H6 + 7/2O2 2CO2 +3H2O

ethane

C10H20 + 15O2 10CO2 +10H2O

decene

C6H14 + 19/2O2 6CO2 +7H2O

hexane

C2H2+5/2O2 2CO2+H2O

ethene

Oxidation of Iron or combustion of iron

4Fe+3O2 2Fe2O3

Oxidation of glucose or burning of food

C6H12O6 + 6O2 6CO2 +6H2O + heat

Reaction of oxygen with nitric oxide

2NO+O2 2NO2

Reaction of Magnesium to form magnesium oxide

2Mg + O2 2MgO

Formation of Sulfur trioxide or combustion of sulfur trioxide

2SO 2+O2 2SO3

Oxidation of Ammonia

4NH 3+ 3O 2 2NO2 +   6H2O

Oxidation of Aluminium

4Al +3O2 2Al2O3(white)

Combustion or oxidation of H2S

2H2S+3O2 2SO2+2H2O

Oxidation of Zinc

2Zn +O2 2ZnO (Yellow when hot white cold)

Oxidation of Carbon disulfide

CS2+3O2 CO2+2SO2

Oxidation of lead

Pb+O2 2PbO (Yellow)

Oxidation of Zinc sulfide

2ZnS+3O2 2ZnO+2SO2

Oxidation of copper

Cu+O2 2CuO (black)

Oxidation of mercury

2Hg +O2 2HgO (red)

C2H2OH 7O2

Catalytic nature of water

4Fe + 3O2 2Fe2O3

H2OH2 +1/2 O2

4P + 5SO2 2P2O5 + 5S

 

Example of hydrated Compounds with Common names and Formulae

Barium chloride dihydrate BaCl2 .2H2O

Calcium sulphate dihydrate or Gypsum CaSO2.2H2O

Copper nitrate trihydrate Cu(NO3)2.3H2O

Copper II chloride tetrahydrate CuCl2.4H2O

Copper II sulphate pentrahydrate or Blue vitriol CuSO2.5H2O

Calcium chloride hexahydrate or CaCl2.6H2O

Iron (II) sulphate heptahydrate or Green vitriol FeSO4.7H2 O

Zinc sulphate heptahydrate or White vitriol ZnSO4.7H4O

Magnesium sulphate heptahydrate or Epsom salt MgSO4.7H2O

Sodium carbonate decahydrote or Washing soda Na2CO3.10H2O

Sodium sulphate decahydrate or Glauber's salt Na2SO4.10H2O

Efflorescence ---- When exposed to air lose their water of crystallization and transformed to powder substance .for example Na2CO3.10H2O

Deliquescent crystals ----When exposed to air lose their water of crystallization and transformed to saturated solutions.

For example CuSO4.5H2O ,when exposed to air at ordinary temperature it absorbs water from air and becomes a saturated solution.

CaCl2,6H2O, MgCl2. 6H2O , NaOH, KOH, ZnCl2, Zn (NO3)2,Cu(NO3)2

Hygroscopic Substances absorb moisture without dissolving in water

CaCl2 , MgCl2 , H2SO4,CaO, P2O2, CuO ,silica gel alcohol.

List of some Important Solvents

•  S in Carbon DiSulfide CS2

•  Paraffin wax in turpentine

•  Rubber in benzene

•  Iodine in Ethylalcohol

•  Paint in turpentine

•  Niter in water

•  Nail Polish in Acetone

•  Rust in oxlalic acid

•  Chlorophyll in Methylated sprint

•  Oil in Petrol

Flame tests :

As Arsenic Blue

B Boron Bright green

Ba Barium Pale/Apple green

Ca Calcium Brick red

Cs Caesium Blue - [Violet (color)Violet]

Cu(I) Copper(I) Blue

Cu(II) Copper(II) (non-halide) Green

Cu(II) Copper(II) (halide) Blue-green

Fe Iron Gold

In Indium Blue

K Potassium [[Lilac (colour)|Lilac](violet]

Li Lithium Pink-Red

Mg Magnesium Bright white

Mo Molybdenum Yellowish green

Na Sodium Intense yellow

P Phosphorus Pale bluish green

Pb Lead Blue

Rb Rubidium Red-violet

Sb Antimony Pale green

Se Selenium Azure blue

Sr Strontium Red

Te Tellurium Pale green

Tl Thallium Pure green

Zn Zinc Bluish green

Copper Compound Lithium Compound Potassium Compound Sodium Compound

Home I How it works I FAQ I Contact Me I Free Homework Help I Quizzes I My Blog
High School Chemistry
College Chemistry
Test Prep Chemistry
Physics
Math
Biology
website security
Copyright 2001-2014 chemtopper.com - All Rights Reserved