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Here is a set of chemistry related questions? 1.) Calculate the theoretical number of moles of HCl equivalent to 1 mole of a.) NaHCO3 b.) CaCO3 c.) AlCO3 2.) How many milligrams of NaHCO3 are in a 500-mg tablet if 40.00mL of 0.120 MHCl is required to neutralize the sample. 3.) An antacid preparation of Na2CO3 claims that a 3.00 gram tablet contains enough antacid to neutralize full stomach acid (0.100M HCl). Assuming that the average stomach contains 0.750L of acid, calculate the moles of NA2CO3 in the antacid. Refute or defend the claim. Guys..really need your help for my assignment..thank you in advance for answering :) I also need some sample calculations so I can review how you did came up with the answer :) tnx

HPV replied: "1. Carbonates (CO3 2-) and bicarbonates (HCO3-) are weak bases that react with acids to form a salt, CO2, and water. That's why they're used as antacids for the stomach. Write out the balanced equation to see what the mole ratio of acid to base is. a) NaHCO3 + HCl ==> NaCl + CO2 + H2O Here the balanced equation tells us that one mole of acid reacts with one mole of NaHCO3. b) CaCO3 + 2HCl ==> CaCl2 + CO2 + H2O Here you need TWO moles of acid for every one mole of CaCO3. c) The correct formula for aluminum carbonate is Al2(CO3)3. Al2(CO3)3 + 6HCl ==> 2AlCl3 + 3CO2 + 3H2O In this case it takes SIX moles of acid to react with one mole of Al2(CO3)3. ================================================== 2. NaHCO3 + HCl ==> NaCl + CO2 + H2O moles HCl = M HCl x L HCl = (0.120)(0.04000) = 0.00480 moles HCl The balanced equation tells us that there is a 1:1 mole ratio of HCl to NaHCO3. So moles HCl = moles NaHCO3 = 0.00480. 0.00480 moles NaHCO3 x (84.0 g NaHCO3 / 1 mole NaHCO3) = 0.403 g NaHCO3 = 403 mg ================================================== 3. moles of stomach acid (HCl) = M HCl x L HCl = (0.100)(0.750) = 0.0750 moles HCl The balanced equation is Na2CO3 + 2HCl ==> 2NaCl + CO2 + H2O There are TWO moles of HCl for every one mole of Na2CO3. 0.0750 moles HCl x (1 mole Na2CO3 / 2 moles HCl) = 0.0375 moles Na2CO3 0.0375 moles Na2CO3 x (106 g Na2CO3 / 1 mole Na2CO3) = 3.98 g Na2CO3 SOOOOO, the stomach acid would require 3.98 g of Na2CO3 to neutralize it. A 3.00-g tablet WON'T DO THE JOB!!!"

Somu replied: "1a) NaHCO3 + HCl ------->NaCl + H2O + CO2 1 mol NaHCO3 reacts with 1 mol HCl Ans: 1 mol b) CaCO3 + 2HCl => CaCl2 + CO2 + H2O 1 mol CaCO3 reacts with 2 moles HCl Ans: 2 moles c) Are you sure it is AlCO3 and not Al2(CO3)3 ? 2)40.00 ml of 0.120 M HCl = 40.00 x 10^-3 L of 0.120 M HCl = 40.00 x 10^-3 x 0.120 mol HCl = 4.800 x 10^-3 mol HCl NaHCO3 + HCl ------->NaCl + H2O + CO2 1 mol HCl reacts with 1 mol NaHCO3 Therefore 4.800 x 10^-3 mol HCl reacts with 4.800 x 10^-3 mol NaHCO3 Molar mass of NaHCO3 = 23+1+12+16*3 = 84 g/mol Therefore 4.800 x 10^-3 mol NaHCO3 = 4.800 x 10^-3 * 84 g NaHCO3 = 403.2 x 10^-3 g NaHCO3 = 403.2 mg NaHCO3 Ans: 403.2 mg 3) No. of moles of HCl = 0.750 * 0.100 = 0.075 Na2CO3 + 2HCl = 2NaCl + H2O + CO2 The above equation shows that the number of moles of Na2CO3 is half of the number of moles of HCl. Therefore, no. of moles of Na2CO3 is at least 0.075/2 = 0.0375 This is the "at least" value because the tablet may contain Na2CO3 more than required to neutralize the HCl. Molecular weight of Na2CO3 = 106 g/mol Therefore, mass of the tablet should be at least 0.0375 * 106 = 3.975 g But the tablet is only 3.0 g. Therefore the claim is wrong. Ans: Number of moles of Na2CO3 = 0.0375 or more The claim is wrong because given mass the tablet cannot contain so many moles of Na2CO3"

How many representative particles r there in 1.45 g of a molecular compound wit a gram molecular mass of 237 g its for a chemistry final review and i dont remember how to set up the problem. HELP PLEASE!

Dr.A replied: "1.45 g / 237 g/mol = 0.00612 moles"

E~Z replied: "Ima student too kidd... Im studying too and if I remember right this is how.... your should know that you use dimensional anaylsis (sp?) right?? put the given info in the first box then to get rid of grams you need 1.45g in the box to the bottom right of the given information. Then you put 1 mole above 1.45 and then place 1 mole again in the box to the bottom right of the this 1 mole. Then put 6.02 x 10^23 above the final one mole... multiply to tops and bottoms then divide like normal. If im wrong anyone dont be mean just put the right answer. 237g..I..1mole...I..6.02X10^23 _____I________I_________________________ .........I1.45g......I...1mole Any units that are diagnal from top to bottom right like the g's (237g and 1.45g) and the moles (1 mole and 1 mole) will cancel - only the units not the numbers u need the numbers to do the calculations............................... i got 9.84 x 10^25. If this is not wat you ment... srry for wastin your time. Hope I helped (1 mole = 6.02 x 10^23 particals = Molar Mass (g)) Sorry bout the equation ( dont worry bout the periods and connect the lines to make kinda sorta boxes!)"

Help with my chemistry midterm review? I swear I'm not lazy. I'm only asking because I genuinely cannot figure out the answer and I've already tried. It's only a few questions on the first side of my review sheet. 3.SI base unit of temperature= K, Kelvin length= m, meter mass= kg, kilogram density= pressure= Pa, pascal 13.How would you separate these mixtures? Sand and sugar= Two colorless liquids= Coffee grounds and water= Sand and saltwater= Iron filings and sands= 16.Sterling silver, brass, bronze, and steel are all examples of alloys, homogeneous mixtures that exhibit properties of ________. 22. ____ is the process (not requiring energy) by which unstable nuclei lose energy. 23.The ______________ ___________ is the set of frequencies of the electromagnetic waves emitted by the atoms of an element. Part of it I just can't figure out, and part of it is just my brain not working right due to stupidity/sleepiness. You don't have to answer all of them because I realize this isn't your chemistry homework, it's mine, and I hate it when people are too lazy to do their own homework, too, but this isn't laziness, it really isn't, it's just me not knowing. But if you can help out, I will be must obliged! Thank-you very, very much!! Hayley. : )

aaj replied: "OK Hayley, such a nice way of asking I can`t resist! 3. Density is actully a derived unit kg/m3 13. Sand and sugar, dissolve sugar in water, filter to get sand, evaporate water to obtain sugar. Two colourless liquids assuming differing boiling temperatures use distillation apparatus. Filter to remove coffee grounds, (which reminds me time for coffee) Filter to remove sand, heat to obtain sea salt Use a magnet 16 properties that are different to pure metal, usually superior for intended use. 22. Gamma emission 23. Emission spectrum Stange mix some are so easy some intermediate GL"

Need help with calculating the mass of solids at different concentrations!? I'm going back to school and trying to review some chemistry problems. I'm lost on the following: calculate the mass of solid needed for 100 ml of a solution that is 0.7 m in chloride anion, using magnesium chloride. I'm looking to see how you set this up to find this answer, and what solutions and amounts you would prepare if doing this in a lab. I want to get a baseline to go by just to see how to do problems such as these. Thanks!

That guy replied: "assuming the equation is MgCl2 <-> Mg2+ +2Cl- you have the conc of cl, and the volume of the solution..... using C=n/V you can find the number of moles of chlorine.... note that the mole ratio is 2:1 btn cl- and mgcl2.....so divide the moles by 2 you have the moles of MgCl2, you can find the mass by * it by MW"

reallyloudzoy replied: "I'm taking it that you need to know how to prepare 100 mL of a 1 molar solution using magnesium chloride. 1- Find the molecular formula of magnesium chloride (you will be adding this to water, and it's a salt that will dissociate to provide those chloride anions, Cl-. = MgCl2 2- Consider the appropriate reaction equation, and balance. = MgCl2 ---> Mg2+ + 2Cl- (noting that a molecule of magnesium chloride dissociates into 1 Mg cation and 2 chloride anions.... this is important since you KNOW the target amount of Cl-, you WANT the amount of MgCl2 solid you'd need to dissolve to achieve the .7M Cl- concentration. 3- Find the number of moles MgCl2 required. Since MgCl2 --> Mg2+ + 2Cl- then moles MgCl2 = 2 * moles Cl Where # moles Cl- may be found from the concentration: Concentration * Volume = Moles .7 mol / L * (100mL / 1000) = .07 moles Cl- = 2Cl- From the in step 3, you can plug in Moles Cl (note that the half comes from dividing out that 2, since to get 2 Chloride you only need 1 molecule of MgCl2). 1/2 Moles MgCl2 = .07 =0.0035 4- Convert Moles to Mass using molecular weight. Moles * Molecular Mass = Mass (note: the molecular mass of anhydrous MgCl2 is 95.211 grams per mole) So .0035 * 95.211 = Mass MgCl2 required. Hope that helps a bit!"

Trevor H replied: "Molar mass MgCl2 = 24.305+35.453+35.453 =95.211g/mol Look at the dissociation of MgCl2: MgCl2 Mg 2+ + 2Cl- 1mol of MgCl2 will give you 2mol of Cl- ions You want a solution that is 0.7M in Cl- ions Therefore your solution must be 0.35M in MgCl2 0.35M MgCl2 = 95.211*0.35 = 33.324g MgCl2 per 1000ml solution But you want 100ml only 100/1000*33.324 = 3.324g Answer: dissolve 3.324g MgCl2 in 100ml solution and [Cl-] = 0.7 Note: If you work in MOLAR solutions, remember to write 0.7M. If you write 0.7m, this has another meaning. In this problem I have assumed that you want 0.7M solution."

chemistry easy review help please?!? okay so i cant find a good way to answer this specifically without rambling on.. differentiate between an observation and an interpretation. give 3 sets of examples that illustrates the differences between observations and interpretations. can you please help me with this, and thank you so much for talking the time to read this!

cinger replied: "observation: ice melting interpretation: ice is gaining heat. observation: sun is setting interpretation: earth is spinning observation: baking soda/vinegar volcano exploding interpretation: chemical reaction producing C02 gas by reacting bicarbonate in baking soda with acetic acid in vinegar. NaHCO3 (aq) + CH3COOH (aq) ----> CO2 (g) + H2O (l) + CH3COONa (aq)"

Chemistry help please I am so upset Im crying because my mom wont let me go to sleep until I figure this out? I would appreciate any help I can get , I am going to list five of the problems that I dont get, I understand the other 15. This is a review for my chemistry test and I got a D on the first one because I didnt understand some problems so this time I want to make sure I know how to get these answers so that I do well on this test because its really important to me! Any help at all would be greatly appreciated! Thank you in advance and if theres anything I can do to help you just let me know in your responce and i'd be happy to give advice ect.. 1. Calculate the wavelength in both nm and angstroms associated with 1 mole of electrons in the hydrogen atom falling from level 4-->1. In what part of the electromagnetic spectrum does this wavelength fit? 2. Calculate the deBroglie wavelength for an alpha particle moving at a velosity of 15% the speed of light. Express this wavelength in meters, nanometers and picometers. 3. Write the valance configuration for the following: Br, Zn, Cl 1-, Ba 2+, and Al. 4. Write a complete set of quantum numbers for all the "d" electrons in an atom of vanadium. 5. Using the noble gas core technique, write the electron configuration for atoms of Cs, Mg, S, I and Sc.

Jacki replied: "chemistry is a tricky subject. i didn't do well in high school , in college i got a tutor and it helped a lot. I would suggest getting a tutor and you should succeed in your college studies, getting the answers on the computer doesn't teach you as well as a tutor or extra help from your teacher would good luck."

PLeasee help me with chemistry problems I am having a really hard time with a few questions Pretty please help? I would appreciate any help I can get , I am going to list five of the problems that I dont get, I understand the other 15. This is a review for my chemistry test and I got a D on the first one because I didnt understand some problems so this time I want to make sure I know how to get these answers so that I do well on this test because its really important to me! Any help at all would be greatly appreciated! Thank you in advance and if theres anything I can do to help you just let me know in your responce and i'd be happy to give advice ect.. 1. Calculate the wavelength in both nm and angstroms associated with 1 mole of electrons in the hydrogen atom falling from level 4-->1. In what part of the electromagnetic spectrum does this wavelength fit? 2. Calculate the deBroglie wavelength for an alpha particle moving at a velosity of 15% the speed of light. Express this wavelength in meters, nanometers and picometers. 3. Write the valance configuration for the following: Br, Zn, Cl 1-, Ba 2+, and Al. 4. Write a complete set of quantum numbers for all the "d" electrons in an atom of vanadium. 5. Using the noble gas core technique, write the electron configuration for atoms of Cs, Mg, S, I and Sc.

oswaldeugene replied: "good morning jackie the two of us are on the same ship! i don't understand chemistry either! let's figure these chemistry questions one on one right now! really! i am almost in tears myself! please write back to me okay. here is my email address. "

Chemistry oh boyyy need urgent help for test? So I'm working on doing a review for a stoich test, and I managed to set up the equation of CaCO3+ 2HCl----> CaCl2 + CO2 + H20 And the question says calculate the mass of carbon dioxide which would be produced by the complete reaction of 2.77 of calcium carbonate in excess acid. So I understand the calcium carbonate is the limiting reactant..but how do I go about doing this problem ? :/

jpsazii replied: "1.22 g CO2 I'm assuming that the 2.77 is in grams (as opposed to moles). First, you need to convert from grams of CaCO3 to moles of CaCO3; to do this, you need the molar mass of CaCO3. Ca: 1 x 40.08 g/mol = 40.08 g/mol C: 1 x 12.01 g/mol = 12.01 g/mol O: 3 x 16.00 g/mol = 48.00 g/mol ===================== CaCO3 = 100.09 g/mol Then use this as a conversion factor: (2.77 g CaCO3) x (1 mol CaCO3)/(100.09 g CaCO3) = 0.0277 mol CaCO3 Next, use a mole ratio to compare moles of CaCO3 to moles of CO2. Using the balanced chemical equation, you see that CaCO3 and CO2 are present on a 1:1 basis. (0.0277 mol CaCO3) x (1 mol CO2)/(1 mol CaCO3) = 0.0277 mol CO2 Next, you need to convert from moles of CO2 to grams of CO2. To do this, you need the molar mass of CO2. C: 1 x 12.01 g/mol = 12.01 g/mol O: 2 x 16.00 g/mol = 32.00 g/mol ===================== CO2: 44.01 g/mol Then use this as a conversion factor: (0.0277 mol CO2) x (44.01 g CO2)/(1 mol CO2) = 1.22 g CO2 I hope this helps!"

How does temperature affect the absorption of light (of a solution)? This is my experiment for chemistry. I am going to mix kool aid with water and have one experiment set at room temperature...one at a cooler temperature and one at a warmer temperature and see how it affects the absorbance of light....I have to do a literature review and I can't seem to find anything on this. Can anyone help me? Please list your resources if you can.

Himo replied: "since there 's no answers yet, you may try to Google it!"

Can someone explain quantum numbers once and for all? I've never understood quantum numbers. I'm taking AP Chemistry and questions like "How many electrons in a ground-level P atom would have sets of quantum numbers beginning 3, 1...?" keep showing up as review problems on our tests. Thanks in advance for the help.

supastremph replied: "n = primary quantum number, start with 1. l = orbital quantum number, starts with 0 and goes to n - 1. m = magnetic q. #, goes from -l to l in unit steps. so we start with (n,l,m) for n=1 (1,0,0) the "1s" shell, it holds two electrons. for n=2 (2,0,0) the "2s" shell, (2,1,-1), (2,1,0), (2,1,1) the three "2p" shells. You then continue this process until you have enough of shells to accomodate all of the electrons for a given element. If you look at a periodic table, you can see P is full up to the 3d shell, and you need to put 3 electrons in it, so following Hund's rule that would be one in (3,1,-1), (3,1,0) and (3,1,1)"