Grade 9 science, Chemistry?
all of us be conscious of that as quickly as gasoline burns, it produces carbon dioxide and water vapor, so we'd say: gasoline plus air (oxygen, actual) yields carbon dioxide plus water vapor (plus potential)
Grade 9 chemistry help?
When you balance chemical equations, you can only add coefficients to the reactants and products. All you havve to do is make the number of each element in the equation equal to the same elements on the other side. Guessing works, and as you keep doing them, balancing becomes easier and easier. Fe + S8 --> Fe2S3 Find the GCF of 8 and 3 for sulfur and add appropriate coefficients to balance those: Fe + 3S8 --> 8Fe2S3 Now there are 16 irons on the right side and one on the left. Balance it: 16Fe + 3S8 --> 8Fe2S3 CuO --> Cu + O2 First, balance the oxygens: 2CuO --> Cu + O2 Then =, balance copper: 2CuO --> 2Cu + O2 Cu + AgNO3 --> Ag + Cu(NO3)2 Balance the nitrates: Cu + 2AgNO3 --> Ag + Cu(NO3)2 Balance silver: Cu + 2AgNO3 --> 2Ag + Cu(NO3)2 try the last one by yourself:) Guessing will work out eventually for simple reactions. For ionic compounds, the overall charge of the compound must be zero, so all you have to do is have a number of each element to make the charge of the compound neutral. Na- + F+ both are plus one and minus one charges, so a 1 to 1 ratio works. Na + F --> NaF K+ + S2- K only has half the charge of S, so twice the amount is needed to neutralize the compound. K + 2S2- --> K2S Ni2+ + SO4(2-) these are 1 to 1 ratio in charge. Ni + SO4 --> NiSO4 Al3+ + O2- this one is harder. you need to find the GCF of the charges and make the charges equal that number. In this case, the GCF is 6. 2Al3+ + 3O2- --> Al2O3 try the last one on your own. Symbols of ions are the element symbol with its charge. Count the amount of ions in the compound for its amount. Na2CO3: there are 2 Na, 1 C, and 3 O. You know that Na has a charge of +1 and O has 2-, so the charge of C must be 2, to counter the -2 charge of the compound without C. Names of salts are the name of the metal and the "ide" of the nonmetal. Na2S: sodium sulfide Al2O3: aluminum oxide NaCl: sodium chloride try the last two:)
Grade 9 chemistry help?
A. It is a physical change because the water is still water, and the copper is still copper sulfate. It has just been diluted. B. The steel wool added into a copper solution will result in the steel wool tuning into copper metal. Chemical change because the steel wool is no longer steel wool. It's copper. I'm not sure about "C", but here is what I think: Na2CO3 + CuSO4 ---> Na2SO4 + CuCO3 Chemical. The sodium carbonate is now sodium sulfate, and the copper sulfate is now a copper carbonate. They are no longer the same substance. D. Magnesium and hydrochloric acid is most certainly a chemical change. If they are mixed in water, the H2O + HCl will dissolve some of the water and leave H2 gas behind. The Mg will completely be dissolved. The substances have completely changed their composition, thus they are chemical.
A2A,See,for boards you can simply go with S.chand publication by lakhmir singh and manjit kaur. Theory of this book is written in a very convenient way,so here is the book,For competitive examination- Pearson's publication is a great book . Remember this series is indispensable for only those students who intends to crack the exams such as KVPY,NTSE, IIT-JEE and several Olympiads . You can buy it from online or your nearby stores,Pearson's books are not for those students whom are procrastinating nature for their studies.Study hard.:)Thanks.
Grade 9 science help: chemistry!?
Atoms will tend to take on the same electron configuration as the elements nearest NOBLE gas. Take Beryllium. It is a metal so it will LOSE electrons to look like its nearest NOBLE gas which is element number Helium. In order to do that it must LOSE 2 electrons and therefore take on a +2 charge. Nitrogen is element number 7. Its nearest NOBLE gas is Neon.. In order to look like Neon it will ACCEPT 3 electrons for a total of 10, just like NEON. It's charge is now -3 S is number 16 with 16 electrons. the nearest NOBLE gas is Argon with 18 electrons. Therefore S will Gain 2 electrons for a total of 18 and have a -2 charge.
Grade 9 chemistry question?
True or false 1. False, mercury is liquid at room temp 2. True 3. True 4. True 5. False 6. False Multiple choice 1. a 2. a 3. a Boiling water - Water boiling, is a physical change and not a chemical change because the simplest way to put it is that physical change is something you can reverse such as melting or freezing of ice, where as chemical change is not reversible. But you can reverse the evaporation which eventually becomes water again (rain). So water boiling is in fact a physical change. Burning candle wax - Burning of any type is a chemical change (unless we are talking about the "burning" that goes on in stars). You are taking two or more substances and combining them to create one or more new compounds and releasing energy in the process. In the case of burning wax, you are combining oxygen with paraffin. The reaction creates carbon dioxide, water and some soot + a release of energy. This is a chemical reaction. The energy released does also melt the wax, which is a physical change, but this is not directly involved in the burning itself.
Grade 9 Chemistry, Formulas Easy?
nicely, ClBr is an quite no longer likely candidate because of the fact nonmetals like Cl2 Br2 F2, etc regularly do no longer clearly bond with one yet another. ClBr might even have an universal charge of -2 and may well be an ionic molecule. it rather is totally no longer likely that a reaction like that would happen. In single replace reactions you turn one ion with a undeniable form of charge with yet another with the comparable charge. Br has a charge of -a million and Cl has a charge of -a million. they may well be switched interchangeably. So enable's say in case you had Li + NaBr, the consequence may well be: Li+ NaBr --> Na +LiBr. Na has a charge of +a million and Li has a charge of +a million so as that they may well be switched interchangeably. Switching Cl and Na would not paintings because of the fact one is valuable and one is unfavourable. you may't change oppositely charged ions with one yet another in single replace reactions.
In what grade do they begin to teach you chemistry?
Chemistry is generally taught in the tenth grade, during your sophomore year of high school. There are exceptions to this, though. If you pass the biology regent in eighth grade you may be allowed to skip bio in ninth grade and move straight to chem, and if you fail chemistry in tenth grade you may have to retake it during your junior year. Me, I'll be taking chemistry next year, when I'm a sophomore. -- Rosie ♥
Some questions on grade 9 chem!?
1.Which one of the followin is incorrect? a-Coolin is prducd durin meltin b-temp. chngs steadily on heatin c-meltin point of ice is 0C d-once meltin starts, temp stays at 0C until all da ice hs meltd 2.meltin is a-endothermic process b-exothermic process c-both d-none 3. whn heat is suppld 2 a solid substncs, a-the kinetic energy of partcles increases b-the potential energy of partcles increases c-the potential energy of partcles decreases 4.Why does water become cold f v add some ice cubes to it?(2-3 lynz) 5. Particles of a liquid- a- are most orderd b-move randomly c-hav large intermolecular spaces d-can slip and slide ova each othr 6.Which pair will nt exhibit diffusion? a.hydrogen , oxygen b. oxygen and water c. salt, sand d. sugar , water 7. The solid tht wld sublime on heatin a. wax b. solid CO2 c. ice d. butter 8. Buttr may b evaporatd by a.heatin &compression b.heatin,decmpression c.coolin and decmpression d. coolin nd comprsion
Estonian schools teach chemistry as follows:A bit here or there up to year 7, usually in the context of nature studies or geography or some other main subject.Introduction to chemistry and physics in year 7. You get two lessons per week and this sets you up nicely to study chemistry and physics in years 8 and 9.Chemistry and physics begin on their own in year 8, twice a week, and continue until you finish middle school at the end of year 9.High school chemistry usually is made up of three mandatory courses (foundations of chemistry, inorganic chemistry and organic chemistry, which includes alkanes, alkenes, alkynes, aromatic compounds, haloalkanes, alcohols, ethers and amines but not carbonyl compounds or carboxyl acid derivatives) but some schools teach a fourth or fifth, organic chemistry and a choice course which can be chemistry of elements or life chemistry or something of that natureSo you get pure chemistry starting from year 8, if you attend a school in Estonia.