questions

  1. C

    Questions related to precipitation of Fe3+ and Al3+ by Ca(OH)2

    I have a problem to resolve for my upcoming exam. A liquid containing 1mol/L of cobalt (Co2+) as cobalt sulfate is contaminated with iron and aluminum and should be purified by removing these impurities by adding slaked lime (Ca(OH)2). The concentration of individual impurities in the treated...
  2. A

    Moles as Intermediate Questions

    What mass of CuBr is found in 4 L of 0.432 mol/L solution ? I n the boxes below place the following information: the moles of CuBr the molar mass of CuBr the mass of CuBr What mass of KNO3 is found in 0.44 L of 1.55 mol/L solution ? I n the boxes below place the following information: the moles...
  3. R

    Hi im new and have a few chemistry questions

    Why are the following stuctures known as hydrocarbons? (CH3-CH3) (CH2=CH2) (CH2=CH-CH3) (CH2=CH-CH2-CH3) What is compound CH3-CH3 and why is it saturated? Many thanks in advance
  4. N

    Two questions about basic chemistry

    For the first question, I think it obvious that hydrogen gas evolves, but I'm not sure whether it is endothermic or exothermic, of course, Aluminum is more active than Hydrogen. As for the second question, I think it was solved by the law: Concentration1 / number1 = Concentration2 / number2...
  5. S

    Lab Safety Questions

    Hi Everyone. My name is Thomas and I am in my first ever chemistry class at my city college. Happy to be a part of the forum; I find forums to be very useful. A bit of an embarrassing question(s) that was not covered in class but presented on a Lab Safety quiz. I came here because I was unable...
  6. K

    Strange fun with food coloring questions

    When opening an old container of food coloring, a bit of the dried coloring dropped into some water, and immediately began zipping around the surface. I recreated this by putting several drops of food coloring on a piece of plastic wrap, and putting it in the sun to dry. Flexing the plastic...
  7. C

    Cutler questions

    Hello, My name is Dan and I am a bladesmith and cutler from the UK. In my line of work I often come across historical references to chemicals and/or chemical processes that are a bit of a mystery to me. Unfortunately chemistry in general is and always has been a mystery to me, so any help is...
  8. K

    Difficult Stoichiometry Questions?

    Hello, The title really says it all. I was just wondering if anyone could help me by sharing any difficult stoichiometry questions which you may know of. These questions can range from Redox, Solution, Equilibrium constant reactions, Gas-Law problems, Classical-Stoichiometry, Limiting-reagent...
  9. P

    Organic chemistry questions

    I'm taking organic chemistry online and it's such a struggle. The Powerpoints show examples only of problems with no explanation and I am having a hard time. I am on unit 4 out of 5 so I'm almost done but I'm so confused about a few things: 1. I was asking to draw...
  10. P

    Organic chemistry questions, so confused.

    I'm taking organic chemistry online and it's such a struggle. The Powerpoints show examples only of problems with no explanation and I am having a hard time. I am on unit 4 out of 5 so I'm almost done but I'm so confused about a few things: 1. I was asking to draw...
  11. P

    We want to continue the production of questions

    Play no more than a small window into what the new year will bring? On the one hand, we want to continue the production of questions in a rate and quality that we have, which means expanding the most popular and exciting stories to bring some conclusions. We will also cast a critical eye on our...
  12. L

    Some chemistry questions I need help with

    1. a)You put [H2] = 0,70M, [I2] = 0,70M and [HI] =1,50M. And the K value is 49. Decide the equilibrium concentrations. H2 + I2 <-> 2HI b) Which concentration HI gets inserted if the iodine concentration at a new equilibrium is 0,42Molar. The K value is still 49. c) What happens with the...
  13. J

    Help!! Solubility/Acids and bases questions

    Hi, I am currently working on some chemistry homework and struggling hard. The questions deal with solubility and acids and bases. There are three questions in particular that I do not know how to do. 1. What would be the solubility of nickel (II) hydroxide in a 0.05M solution of strontium...
  14. K

    Two Questions I need help

    10 mL of 0.1M HCl was added to 90 mL of water. 10 mL of that solution was added to another 90 mL of water. The student diluted the sample as above another 4 time(s). What is the pH of the solution? 10 mL of 0.1M NaOH was added to 90 mL of water. 10 mL of that solution was added to...
  15. C

    Dilutions questions

    I have an issue where I think I'm just confusing myself with a simple question. Here are the directions I'm following : "Apply 200 ul of 1 nM Fluorescein(375g/mol) in 0.01 M NaOH solution to wells." Assuming total volume is 1L - 10mL NaOH with 990mL H20 should give .01M NaOH I can't...
  16. D

    More AP Chem Questions

    Please someone tell me HOW to do these. NOT the answers!!! I really have no idea whatsoever! :( 1. A gas sample is held at constant pressure. The gas occupies 3.62 L of volume when the temperature is 21.6°C. Determine the temperature at which the volume of the gas is 3.45 L. 309 K 281 K...
  17. M

    A Few Questions OchemII lab

    I'm studying for my lab final, and am doing some practice /review problems. 1. The yield of triphenylmethanol is 30%. Give 2 reasons why the yield is low. Assume no mistake is makde, glass is dry, and oxygen side rxn is regligent. (Shows a grignard rxn). Okay, so I put that 1. although the...
  18. S

    Just a few quick chemistry questions :)

    Hello, I have attempted these answers and will post below how I answered them, but can somebody please clarify if I was correct or incorrect? Thank you! Q1) REFER TO ATTACHMENT IMAGE - Which solution contains the LOWEST CONCENTRATION SPECIES of 'HA'? I had Solution 3 because there is no HA...
  19. D

    These questions need well qualified knowledge. Can you please hep me?

    1) a) 1,3-butadiene is one of the precursors used to produce adipic acid and hexamethylene diamine in petrochemical industry. Write the reaction pathways involved. b) Adipic acid and hexamethylene diamine are the monomers of a type of nylon. Write its repetition unit and succinctly present the...
  20. F

    Questions for my Upcoming Exam

    I cannot answer them... don't understand these questions and exams are just around the corner: Question 1: Investigation of the rate of reaction between HCl acid and pure Magnesium, in which the following curve (Above is obtained) The reaction is exothermic: Explain why, using your...