CHEMISTRY HELP!!!PLEASE?
Muz, you had better STUDY, and study HARD!!!!
Does hydrochloric acid (HCl) react with copper (Cu)?
Copper will not react with hydrochloric acid. For this type of reaction to occur, the reduction potential of the reactant receiving the electrons must be lower than the reduction potential of the reactant giving up electrons. Why, and why does this reaction even involve electrons in the first place?The net reaction that will occur in this case is as follows:[math]Cu+2HCl\rightarrow CuCl_2+H_2[/math]If you notice, I am using the +2 oxidation state of copper, despite there being several possible states, that is simply because +2 is the most common oxidation state of copper. Why this is the case is the topic for another question. This reaction looks perfectly reasonable, it isn't some crazy out there reaction or anything like that, so let's break it down. It is going to be an electrochemical reaction, so we can use an ionic equation to write it out in a little more useful way.[math]Cu+2H^+\rightarrow Cu^{2+}+H_2[/math]So why did we leave the chloride out? Well, because the chloride is not changing. Remember, in solution ions are not bound together, they are simply floating around surrounded by the solvent, so if they are not changing oxidation states, they really are not relevant in most cases. Now, because this is an electrochemical reaction, we can divide this equation into 2 separate equations called half equations, which will really get to the heart of what we are looking for here.[math]Cu\rightarrow Cu^{2+}+2e^-[/math][math]2H^++2e^-\rightarrow H_2[/math]Now we have the equations that we really need to look at to be able to figure out that this reaction will not occur. By definition, the reduction potential of the hydride is 0 V. The reduction potential of the copper is -0.34 V. This means that the copper is holding onto it's electrons more tightly than the hydride is pulling electrons to it, thus no reaction will take place.Also of note, copper is one of the so called "noble metals." Just like the noble gases are gases that do not readily react, the noble metals do not readily react in a lot of cases. They include other elements such as gold, so this phenomenon is not unique to copper by any means.
How do I study for ICSE 10th chemistry? I have concise book.
First of all, I'm sorry about answering this late. I hope your Chemistry exam went well. However, I choose to answer it anyway, so that my answer proves to be beneficial to others who have the same doubts.Most ICSE schools use Viraf Dalal as their Chemistry textbook which is a pretty good book. I haven't used Selina publications for Chemistry, so certain things that I may talk about may not apply to you. Now, instead of telling you what to do and what not to do, I'll just share with you my timetable when it came to studying Chemistry. Set 1:Periodic Table, Hydrogen chloride, Nitric Acid, Metallurgy and Analytical Chemistry. Break time.Set 2:Chemical Bonding, Ammonia, Sulphuric Acid, Electrolysis and Practical Chemistry. Break time. Set 3:Mole Concept, Acid,Bases & Salts and nomenclature of Organic Chemistry.Break time.And I would do the reactions of Organic Chemistry whenever I feel that my brain is active. That's usually after I get up. But general tips would be:1. Make sure you've read all the chapters at least once. 2. In your exam, when observations are asked due to a particular reaction, you are NOT supposed to say which compound it is because it is an OBSERVATION. It's something that you identify with your 5 senses only. 3. Chemistry papers are generally easy. Try attempting all questions. 4. Don't forget, in the case of electronegativity, Chlorine is more than Fluorine. 5. While calculating empirical formula, make a nice table and be neat with your calculations. 6. Under Chemical Bonding, structure coordinate covalent Compounds like hydronium ion and ammonium ion are important. 7. Know the names of the ores very well, when it comes to Metallurgy.8. Usually definitions are asked from Electrolysis. Or they ask you about Hall-Heroult's process.9. Under HCl, NH3, H2SO4 and HNO3, the industrial method of preparation process is very important! And usually, reactions for balancing come from here.10. Organic Chemistry is easy but lengthy. Always write the full structural formula for any compound for better understanding. That's about it. All the best :)