How to do this chemistry question? sophmore in high school level...?
Joseph Priestly discovered oxygen in 1774 by heating "red calx of mercury", mercury(II) oxide. The calx decomposed to its elements. The equation is HgO---------> Hg+O2 (not balanced, and the 2 after the O is little and in the bottom corner) What mass of oxygen is produced by the decomposition of 10.8 grams of Hgo? if you could help me in any way I'd give you 10 points ASAP, thank you soo much(:
Chemistry questions ( high school level), please help?
The last occupied energy sublevel in sodium ion (Na+) is: (a) 2s sublevel (c) 2p sublevel (b) 3s sublevel (d) 3p sublevel --------------------- c Yep. If you were asked to determine the concentration of nitric acid (HNO3) experimentally using pipette, burette and conical flask in addition to a standard solution of sodium hydroxide (NaOH) and a suitable indicator, then the point at which the moles of (NaOH) equal the moles of (HNO3) is called: (a) Freezing point (c) End point (b) Equivalent point (d) Boiling point ------------------------b? Yep, but this is found when there is a color change, which is the end point (usually close to the equiv pt) Which of the following contains a polar covalent bond? (a) H2(g) (c) NaCl(s) (b) Br2(l) (d) HCl(g) ------------------ I understand why HCl is a polar covalent bond. I don't know why NaCl isn't one, Is it because it's a ionic bond? Yes - use the guidlines in your book for determining ionic/polar/covalent. It's usually > 2.0 is ionic, and then between o.5 and 2.o is polar, and anything less than 0.5 is covalent. then just subtract the electronegativities of the atoms. Which of the folowing compounds has the highest percentage by mass of nitrogen (N)? (a) NH3 (17.0 g / mole) (c) N2H4CO (60.0 g / mole) (b) (NH4)2SO4 (132.1 g / mole) (d) NH4NO3 (80.0 g / mole) ---------------------------- a, does it mean the atom N or the whole N mass? Whole N mass (which is about 14 17ths in NH3), but since there is only 1 N in the molecule, there is no difference between the whole N mass and the mass of that N atom. What is the molarity of a solution made by dissolving 285 mg of magnesium bromide (MgBr2) in enough water to make 50 cm3 solution? (a) 0.050 mole / liter (c) 0.285 mole / liter (b) 0.010 mole / liter (d) 0.031 mole / liter -------------------------- I don't know this one M = moles/L of solution. So convert the mg to moles using the molar mass. then convert cm3 to L. then just divide. www.mseAcademics.com
High School Chemistry question?
Imagine the paint as a (very flat) "cylinder." The shape of this cylinder doesn't matter as long as it's uniform, and we're covered there since it asks for the average thickness. The volume of a cylinder is the area of its base times its height: V = Ah You are given the volume (1 gallon) and the area of the base (350 square feet). The units have to match up. There are many ways you could go about doing it, but perhaps the simplest would be to convert 1 gallon to cubic feet (1 gallon = 0.133681 cubic feet, from a standard conversion reference). Divide this by the area and you have the height, though it will be in feet. Then convert this answer to millimeters.
Highschool standard chemistry questions please help?
hey guys! hee's the question! i'm so stuck! please help :) 0.50 mol of I2(g) and 0.50 mol of Br2(g) are placed in a closed flask. The following equilibrium is established. I2(g) + Br2(g) IBr(g) The equilibrium mixture contains 0.80 mol of IBr(g). What is the value of Kc? A. 0.64 B. 1.3 C. 2.6 D. 64 thanksss
What are questions about chemistry that I can get my teacher stuck with?
When you learn the Three States of Matter (Solid, Liquid, Gas) ask them how many others there are.There are More than Three States of Matter... Many More
Please..help me.. my high school chemistry?
1.What is the pressure of 45g of H2 gas that is in a 25.6L container at 25˚C? 2.500ml of a gas is collected at 745 mm HG. What will the volume be at standard pressure? 3.The temperature of a 4L sample of gas is changed from 10.0˚C to 20.0˚C. What will the volume of this gas be at the new temperature, if the pressure is held constand? 4. A gas ballon has a voulme of 106.0 L when the temperature is 45˚C and the pressure is 740 mm of Hg. What will its volume be at 20˚C and 780 mm of Hg pressure? 5. Determine the number of moles of Krypton contained i a 3.25 L gas tank at 5.80 atm and 25.5˚C. 6. In question #5, if the gas was changed from Krypton to oxygen, would your answer be the same? Why or why not? 7.Comapare the velocities of argon gas to bromine gas using Graham's Las of Diffusion. 8. A gas occupies 11.2L at 0.860 atm. What is the pressure if the volume becomes 15.0L? 9. What is the molecular weight of a gas which diffuses 1/50 as fas as hydrogen?
Should I take chemistry in high school? Is it hard?
My school requires all students to take Chemistry to graduate, so needless to say I took Chemistry, and you probably should too.Now, Chemistry itself, at the high school level, is challenging but can be rewarding to students who put in the time and effort to learn and grasp the concept rather than regurgitating information on a test much like Biology. I had the privilege of taking Chemistry Honors at my school, and much to my dismay I received the hardest teacher for the class out of four possible teachers. This teacher taught two classes of Chemistry Honors and three classes of AP Chemistry. It was pretty apparent she didn’t give a hoot about her Honors classes and focused more on her AP classes. However, it must be noted that this teacher does not teach well and gives hard, application-based, tests for each chapter.I struggled with this teacher. Whenever I would ask her a question such as “why does the Oxygen in this equation react like that?”, She would simply brush it off stating the answer is really complex, so it’s better just to know that it reacts this way. That is no way to teach a concept; learning the “why” helps a student retain the information much longer.There is something you need to understand, this teacher has a Ph.D. in Chemistry, does that make her qualified to teach a high school chemistry class, sure, but does it mean she should teach it, no.Luckily, I had a couple of my good friends in the class with me so I could always rely on them for help with the homework or late night study sessions before a test. I also had friends in the other class which is two periods before us meaning I could text them to see what was on the test before I took it. I know that is a form of cheating, but honestly, I would have been stupid not to have done that.Truth be told, High School Chemistry is definitely a rigorous course. Many topics have to be covered, and there is a lot of mathematical calculations toward the second half of the course (at least in my school). There is, however, a greater purpose of Chemistry. Even if you are not interested in becoming a doctor or a chemist after college, Chemistry will teach you about how everything works in life. The periodic table will be your best friend!To answer your question, you absolutely should take Chemistry in High School.
High school chemistry Titration
A titration setup was used to determine the unknown molar concentration of a solution of NaOH. A 1.2M HCL solution was used as the titration standard. The following data were collected. Trial 1 Trial 2 Trial 3 Trial 4 Amount of HCL 10.0mL 10.0 mL 10.0mL 10.0mL standard used Initial NaOH 0.0mL 12.2mL 23.2mL 35.2mL Buret reading Final NaOH 12.2mL 23.2mL 35.2mL 47.7mL buret reading QUESTION : calculate the average molarity of the unknown NaOH solution for all 4 trials. Your answer must include the correct # of significant figures and correct units.
Chemistry question?
I was working on the chemistry olympiad, and I do not understand the answer to this question. (http://www.acs.org/content/dam/acsorg/education/students/highschool/olympiad/pastexams/2014-usnco-local-exam.pdf) Question 41. The cell potential for the voltaic cell depicted below is 0.109 V under standard conditions, 1M Ni2+(aq) and 1 M Pb2+(aq). The picture has the Ni2+ (aq) at the anode side with a Ni electrode, a salt bridge, and the Pb2+(aq) at the cathode side with a Pb electrode. Which change will increase the voltage? (A) The 1 M Ni2+ solution is diluted with H2O. (B) A larger Ni electrode is used. (C) 50 mL of 1 M NaCl solution is added to precipitate PbCl2. (D) More 1 M Pb2+ solution is added to that half-cell I chose C because that would decrease the concentration of the products so then it would increase the voltage. However, the answer is A. Can anyone please explain that? Thank you!
What makes chemistry so hard for so many high school students?
What made it hard for me was that it seemed fairly ‘random’ to me. Physics and Maths are all totally logical, to me, but I couldn’t see any logical reason why certain chemicals reacted in certain ways with other chemicals, or why the results behaved in certain ways.Maybe it was the way it was taught, or the way I learn things, but I’m a ‘modeller’ - I model out how things work in my mind. That often lets me predict things from what I know, and means I just need to remember the ‘models’ rather than lots of odd facts. I struggled to do that with Chemistry. Physics was a piece of cake in comparison, as that was all totally logical.The Maths-y bits of Chemistry (questions about moles etc) were all straightforward, it was the ‘what colour is XXXX?’ or ‘what happens when you add XXX to YYY?’ questions which had, to me, random answers that I had to have memorised specifically, as there’s no way to predict, for instance, which copper compounds would be red, blue, green, black, white, etc. I knew copper compounds were likely to be coloured, but how was I supposed to know that Copper(I) hydroxide is yellow, but Copper(II) hydroxide is blue? There was no logical explanation (that we’d been taught).Personally, I suspect that if I’d studied Chemistry beyond A level, then it would have started to make more sense as the reasons for why things happened that way were explained in more detail.