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Dicentra

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Dicentra last won the day on June 12 2013

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About Dicentra

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    Hive Mind Worker Bee
  • Birthday 03/02/1972

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  1. Based on the wording of the question, the answer would have to be "True". 🙂 You don't need both calcium and magnesium ions to make water hard - in fact, you can have ions other than calcium or magnesium present that would also make water hard. You're correct - it isn't any kind of interaction between calcium and magnesium ions that defines "hardness". Quite often, both calcium and magnesium ions will be present together in a hard water sample because of the geology of the aquifer that the water is coming from (the parent geological formations that would produce hard water would often contain both calcium containing minerals and magnesium containing minerals). You wouldn't need both to be present for the water to be considered hard, though. Hope that helps!
  2. Dicentra

    Outlander

    This might be considered complete and utter sacrilege but... I'm finding I just can't watch any more of Sam Heughan's (Jamie) bad acting. He seems so stiff and unnatural. One is very aware that it's an actor playing a part. Come to think of it, Caitriona Balfe (Claire) is much the same although her acting isn't bothering me as much as Heughan's, for some reason. As repellent as the character of Jonathan Randall is, Tobias Menzies is a fantastic actor. Just my thoughts. 🙂
  3. Carbon Chemistry would only cover one aspect of chemistry - organic chemistry. 🙂 Within that, they would need to do a little explaining of bonding but it isn't going to cover all of the topics that a standard high school chemistry course would cover. In re-reading your question, though, that may not be what you were wondering. 🙂 I don't have any hands-on experience with either curriculum so hopefully someone who does can jump in and give you a comparison. 🙂
  4. Dicentra

    Videos for Pearson Chemistry?

    Did you mean the Prentice Hall Chemistry book? This one? http://www.phschool.com/webcodes10/index.cfm?area=view&wcprefix=cdk&wcsuffix=0000 That link gives you some online quizzes for free. There is a Study.com course that you can try for 30 days for free but I'm not sure if every chapter comes with videos: https://study.com/academy/course/prentice-hall-chemistry-online-textbook-help.html If that isn't the textbook you mean, it might help to get more responses if you can give the exact book. 🙂
  5. My dd will be home on Thursday. We've been to see her perform a few times and she was home for (Canadian) Thanksgiving so I haven't felt like too much time has gone by without a visit. She seems to be loving university and being on her own and I think our relationship has benefited from the time away from one another. 🙂 I wish Thursday would get here sooner!
  6. The teacher may have simply accidentally marked down the incorrect correct answer. 🙂 It's sometimes easy to do with multiple choice questions. Did the teacher stick by the answer when the mistake was pointed out? That would be more worrisome to me. Because yes - energy is released when bonds are formed.
  7. Well, since I don't own a smartphone or a tablet, then I'm already doing it. Can they just pay me the money? 🙂 I have an old Samsung 3S Mini, I think it's called. It has no data. I don't often use it as a phone because the sound is terrible. I sometimes text but will more often use email from my laptop - faster to type. We don't use GPS when driving. DH has a flip phone. I'm not kidding. He says he won't trade it in for an upgrade. Ever. 😄 I do use my laptop all the time for work (online course teaching tends to not really work unless one is... well... online 😉 ) so I couldn't give up computers or the internet. But a smartphone or a tablet? Already there. 🙂
  8. Dicentra

    What should we use for chemistry?

    In a nutshell, that's pretty much it. 🙂 If I were teaching AP Chem out of the AP Chang text (or any AP text, really), I'd add in problems that asked the students to dig deeper and that required them to pull concepts from a couple of different chapters in order to solve the problems. I think that will be the "next step" for students going from my course to AP Chem - using multi-chapter thinking to approach problems. My goal for the Honors Chem course is to give the students a good "first look" at the chapters one at a time (although the exams obviously cover more than one chapter 🙂 ). In Honors Chem, for example, my students would be asked to find a molecular formula by being given experimental mass data - so basically using what they know from Chapter 3. In AP Chem, students might be asked to find a molecular formula by being given experimental data requiring gas law calculations to determine masses and the molar mass - in other words, having to use concepts from both Chapter 3 and Chapter 5 to solve the problem. The AP text will cover much of the same topics as Chang's General Chem text but often make the problems harder (adding in little twists, etc.). Making problems slightly trickier and having more topics are the main differences between Chang's AP text and the non-AP text. 🙂
  9. You're welcome! If it does get stronger, then it's probably something that needs to be looked into. Definitely let me know and we can try to troubleshoot. 🙂
  10. First - congratulations to the boys! 🙂 And yes - if the cupboard had been closed for awhile, the vapors would have built up a bit more from anything that was volatile. I think I can imagine your smell now - it's that "chem lab" smell that all my university chem texts have. It's not really specific to any one compound. Weirdly, I like that smell. But then, I like chemistry. 🙂
  11. The other suggestions are good - selling things (or gifting things) to other homeschool families is probably your best way to go. Regentrude is right about giving the chemicals to a school - they probably can't accept them - but they would probably gladly accept any equipment. If you do end up needing to dispose of the chemicals, talk to your local fire department about hazardous waste disposal. They often have a company that will come in and take away hazardous waste to be disposed of properly so the fire department would probably take the chemicals off your hands and make sure they are disposed of correctly. If some of the chemicals are dilute solutions of ionic salts, those can go down your drain with lots of running water (nothing with heavy metals in it, though). Do not pour organic substances or concentrated acids or bases down your sink - take the organics to the hazardous waste disposal folks and carefully (and correctly) dilute or neutralize the concentrated acids and bases before pouring them down the sink. And no - pouring them down together and letting them neutralize each other in your drain is NOT a good idea. 😉 😄 Some solids could go into regular garbage but others should not - you're welcome to PM me if you aren't sure which are which. 🙂
  12. 😄 It probably is easier to buy a little bit of universal indicator but if you need it today, then we'll work with what you have. Are you making it from anthocyanins (i.e. purple, red, or blue coloured foods)? If so, it should be kind of blue in a neutral solution. A base should turn it yellow, not an acid. This is a nice view of anthocyanin colours in a variety of pHs: Acidic is on the left, neutral in the middle, and basic is on the right.
  13. Is it the Honors kit or the Standard kit, Meriwether? How long have you had the kit (i.e. how old are the chemicals)? In either kit, the only somewhat concentrated solutions you have are the 6.0 M ones - acetic acid, ammonia, hydrochloric acid, and sodium hydroxide. The phenolphthalein will be in a solution of alcohol, as will the iodine and any other indicators, most likely. The other solutions all seem to be quite dilute aqueous solutions that shouldn't have any smell and wouldn't be volatile. Do you have the ammonia and hydrochloric acid in the same tub? If so, they should be separated. I would take the ammonia solution and store it in a different cupboard, if you can, but not near bleach. If a different cupboard isn't an option, just make sure it isn't in the same tub as the hydrochloric acid. If you have the Honors kits, the salicylic acid could be breaking down in high heat and humidity and producing an acrid kind of smell but it's probably unlikely.
  14. Yup - acetone is the compound in nail polish remover. After you aired out your house, @Meriwether, did the smell come back? If it didn't come back, then it probably isn't something that in your house. The smell could have come from outside and was carried in through an open window or through your air exchange system for the house. In terms of storage safety, most things that would be real issues aren't legally available for purchase outside professional or academic labs so you probably don't have any of them. 🙂 If you've got any organic substances (things like acetone or any alcohols, esters, ethers, other ketones, aldehydes), those would be most likely be your culprits. Most non-organic substances wouldn't be volatile enough to give off a strong scent, particularly in the amounts that most homeschoolers would have. This is meant for a lab setting but gives some advice as to where certain families of compounds should be stored in relation to one another: https://www.cmich.edu/fas/fsr/rm/EHS/Documents/chemical storage guidance.pdf Flinn Scientific used to have a whole chemical storage safety section of their catalogue that was basically free info on how to safely store your chemicals but now it looks like one has to buy the info. 😞 In general, store your oxidizers separately (chlorates, nitrates, permanganates), store your strong acids separately, particularly if they are also concentrated, i.e. not diluted (hydrochloric acid, sulfuric acid, nitric acid), and store your organic substances separately from everything else and make sure that the cabinet that they are stored in isn't sealed air-tight. You don't want flammable vapour building up inside the cabinet. 🙂 The one compound that can cause real problems if left to sit is hydrogen peroxide but not at the concentrations that are solid in the supermarket or drug store. If you have any 30% hydrogen peroxide, it can break down in the bottle into water and pure oxygen gas which can then explode if exposed to heat or a spark. I don't think the average person can buy 30% hydrogen peroxide, though, so you're probably OK there. Feel free to PM me with a picture of what's stored in your cabinet (preferably with close-ups so I can read labels 🙂 ) and I can tell you if you've got anything worrisome.
  15. Can you describe the smell? Is it like vinegar? Or solvent-like? Or something else? I might be able to help you narrow it down if you can describe the smell. 🙂
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