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daniaridha

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    Female
  • Exams
    May 2015
  • Country
    Canada

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  1. daniaridha

    Stochiometry Question (PLEASE HELP!)

    I would REALLY appreciate some full explanation for this question. The thermal decomposition of sodium hydrogen carbonate, NaHCo3, results in a 73.8% yield of sodium carbonate, Na2Co3. 2NaHCo3=Na2Co3+H2O+Co2 If a 1.68 g sample of sodium hydrogen carbonate is heated, calculate the mass, in g, of sodium carbonate produced.
  2. daniaridha

    Stochiometry Question (PLEASE HELP!)

    I would REALLY appreciate some full explanation for this question. The thermal decomposition of sodium hydrogen carbonate, NaHCo3, results in a 73.8% yield of sodium carbonate, Na2Co3. 2NaHCo3=Na2Co3+H2O+Co2 If a 1.68 g sample of sodium hydrogen carbonate is heated, calculate the mass, in g, of sodium carbonate produced.
  3. daniaridha

    HL/SL Chemistry Question

    Hi, I would really appreciate a full explanation of the process of the following question Chlorine gas is produced by the reaction hydrochloric acid, and the oxidizing agent manganese (IV) oxide, MnO2: MnO2+ 4HCl = MnCl2 + Cl2 + 2H2O At 273.15 K and 100 Pa, 58.34 g of HCl reacts with 0.35 mol of MnO2 to produce 7.056 dm^-3 of chlorine gas. Deduce the limiting reagent, and calculate the theoretical yield of chlorine.
  4. daniaridha

    Stochiometry Question

    A solution of 155 g of potassium iodide, KI is added to a solution of 175 g of nitric acid, HNO3. The acid acts as an oxidizing agent. 6KI + 8HNO3= 6KNO3+2NO+3I2+4H2O A) Deduce which reagent is in excess. B) Determine how many grams of this reactant will remain unreacted. C) Determine how many grams of nitrogen monoxide, NO will be produced.
  5. Hi everyone, if someone could please explain the following question's process to solving the answer it would be highly appreciated 1. Potassium superoxide, KO2, reacts with carbon dioxide, CO2, to produce oxygen and potassium carbonate, K2CO3. Write the balanced equation for this reaction (I already did this- 4KO2+2CO2=3O2+2K2CO3). 28.44 g of KO2 reacts with 22.00 g of CO2. Deduce the limiting reagent, calculate the mass of K2CO3 produced as well as the mass of O2 produced.
  6. Hi everyone, I am trying to revise for my test Monday and I am in need of a little help. Could one please explain the full process of receiving the answer to the following question? It would be GREATLY appreciated
  7. Hi, I would really appreciate some clarification on whether or not I executed the correct process for the following question: Ethyne, C2H2, reacts with oxygen according to 2C2H2+5O2=4CO2+2H2O. What volume of oxygen, in dm3, reacts with 0.40 dm3 of C2H2? Initially, I recognized the ratio of ethyne to oxygen to be 2:5. Then, I cross multiplied 2/5=0.40/x. I received the answer as 1 dm3. Is this correct?
  8. Hi everyone, I would really appreciate some help in solving the following question. I did the process but I wanted to ensure that I achieved the correct answer. Thank you Two aqueous solutions, one containing 5.3 g of sodium carbonate and the other 7.0 g of calcium chloride, are mixed together. A precipitation reaction occurs: Na2CO3+CaCl2=2NaCl+CaCO3 Determine the limiting reagent and the mass, in g, of precipitate formed (theoretical yield).
  9. daniaridha

    Biology HL/SL Help!

    Hi everyone, if anyone could please explain how to calculate the magnification of a scale bar that would be highly appreciated. For instance, if you are given a scale bar represented by a 2 micrometre value, and when I measured the scale bar itself it came to 1.8 cm, and the answer is X 8500, how would would actually achieve that answer? Thanks!
  10. daniaridha

    SL/HL Biology Question

    If someone could please explain the process of how to calculate magnification given scale bars, that would be greatly appreciated! For instance, the length of a scale bar given is 2 micrometres. When I actually measure the length of the bar, it comes to 1.8 cm. The answer is X 8500. How would I receive this answer?
  11. If you could please help explain the process of how to solve this question, that would be greatly appreciated 1. Butane lighters work by the release and combustion of pressurized butane. 2C4H10+13O2=8CO2+10H2O Determine the limiting reagent in the following reaction. a) 20 molecules of C4H10 and 100 molecules of O2.
  12. daniaridha

    SL/HL Chemistry Question (Please Help!)

    This has been extremely helpful!! Below I have written some of my workings. I am just getting a little confused after the point where I stopped at. Could you please guide me from there? Thank you so so much. 1. The equation is already balanced. 2. I found the # of moles in SA and that was 0.021 mol. The # of moles in AA were 0.039 mol. 3. To find the limiting reagent, I used the mole ratios (1:1) and then cross multiplied. I learned that in 0.021 mol of C7H6O3, I need 0.021 mol of C4H603. We have 0.039 mol of C4H6O3 therefore it is in excess. What would I do from there? Sooo... Assuming all of the above is correct (as I haven't checked your working) then I think you've got a bit confused by the limiting reagent bit. Cross multiplying anything is unnecessary. It's really simple. If you need 1 mole SA + 1 mole AA to make 1 mole of Aspirin... And you have 0.021mol SA + 0.039mol AA = ?mol Aspirin Then you've logically got to have made 0.021mol Aspirin, and that's the answer. Yes you've got extra AA but because the ratio is 1:1 then the extra isn't doing anything. Why? Because it's a 1:1 ratio. You have extra AA but it's useless because there's no SA to pair it off with. SA is the limiting factor, so assuming the reaction goes to 100% completion the amount of aspirin has to be equal to the amount of SA. Does that make sense? Thank you so much! This makes sense to me now. You've explained it really well
  13. daniaridha

    SL/HL Chemistry Question (Please Help!)

    This has been extremely helpful!! Below I have written some of my workings. I am just getting a little confused after the point where I stopped at. Could you please guide me from there? Thank you so so much. 1. The equation is already balanced. 2. I found the # of moles in SA and that was 0.021 mol. The # of moles in AA were 0.039 mol. 3. To find the limiting reagent, I used the mole ratios (1:1) and then cross multiplied. I learned that in 0.021 mol of C7H6O3, I need 0.021 mol of C4H603. We have 0.039 mol of C4H6O3 therefore it is in excess. What would I do from there?
  14. daniaridha

    SL/HL Chemistry Question

    Okay, so, I made it to step #4 and I am getting slightly confused. I calculated the limiting reagent to be 0.996 mol of HF because we only have 0.749 mol of HF. Where would I go from there?
  15. If someone could please help me answer this question, that would be great. I am really just trying to learn and understand this process. 1. Acetylsalicylic acid, also known as aspirin, C9H8O4, is synthesized by reacting salicylic acid, C7H6O3, with acetic anhydride, C4H6O3. C7H6O3+C4H6O3=C9H8O4+C2H4O2. a) Calculate the theoretical yield, in g, of aspirin when 3.0 g of salicylic acid is reacted with 4.0 g of acetic anhydride.
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