Help me please!!! Chemistry students only...?
starting HCl moles = .05mol excess HCl moles in 250cm^3 = .02105mol HCl moles reacted with 1.5 g of CaCO3 sample, (starting HCl moles )minus (excess HCl moles )=.05mol - .02105mol = .02895 mol equation: CaCO3(s) + 2HCl(aq) --> CaCl2(aq) + H2O(l) + CO2(g) mole ratio = HCl 2:1 CaCO3 divide by 2 ,( .02895mol / 2 = .014475mol of HCl) grams of CaCO3 = .014475 * 100g = 1.14475g of CaCO3 CaCO3 % = (1.14475g / 1.5g )*100 = 96.5 %
Organic Chemistry help...?
Cyclohexanol is treated with H2SO4 to produce compound A which decolourises bromine in CCl4. Compound A is treated with reagent Y to produce 1,2-cyclohexanediol. Which of the following statements is correct? A could be cyclohexene and Y could be dilute/cold KMnO4 b. A could be cyclohexene and Y could be H2O c. A could be cyclohexane and Y could be dilute/cold KMnO4 d. A could be cyclohexane and Y could be H2O e. B could be cyclohexene and Y could be B2H6/H2O2 followed by OH-
Chemistry Help- Alka Seltzer Problem!?
Hiya, i need help with this question that im am totaly stumped! 1. Find the percent of mass lost by the Alka Seltzer. given: initial mass of Alka Seltzer = 3 grams Alka Seltzer = NaHCO2 (not sure if thats important or not!) mass of CO2 released = 0.704 grams After this im lost please explain the steps take to get the answer please and thank you!
Chemistry question.?
Hiya, I know the answer to this question I was just wondering if somebody could give me an explanation so I could understand it better. Thank you! What is the coefficient for water when the following equation is balanced? As(OH)3[s] + H2SO4[aq] = As2(SO4)3[aq] + H20[l] The answer is "6".
Chemistry help! electron pairs, lone pairs, electronic and molecular geometry?
Lewis Structure: Count number of valence electrons per each atom (that's the number of their group). Br - 7(1) Cl - 7(5) Add together = 7+35 = 42 Choose the atom with the least amount of atoms to be your central atom. All of the other atoms will come off of this atom. Cl Cl Br Cl Cl Cl Make bonds of two electrons each between the central atom and the atoms coming off it. (I can't really show this in type, but it would take away 10 electrons) So, there's 32 electrons left. Use the rest of the electrons to fill the octet of the atoms coming off of the central atom. So, distribute 6 electrons to each Cl. This gives each Cl 3 lone pairs and leaves you with 2 electrons to use. Since the octet of each Cl is used up already, put the extra lone pair on your central atom. (It is okay for Br to expand its octet.) So you have five atoms and one lone pair coming off of Br. Electron pairs = 5 (number of bonds coming off of Br) Lone pairs = 1 The electronic geometry is the general shape of the compound. It has five atoms and one lone pair coming off it. This is basically six things (six pairs of electrons) coming off of Br. Check out your notes or the internet for a list of VSEPR electronic shapes. This one is octahedral. Molecular geometry is more specific. It differentiates between molecules and lone pairs. There's five molecules and one lone pair, which makes it square pyramidal. Good luck on the rest of your homework.
Can I change my honours subject from physics to chemistry in Lady Brabourne College?
Thanks for A2A.Well, yes you can change your honours subject from physics to chemistry. However, for that to happen you are supposed to apply in the Department of Chemistry for admission just as you did for physics. Please note that you can move to the Chemistry department on if you get admission in the department the same way in which you got a seat for physics.Getting a seat in the Department of Physics don't assure a direct transfer to any other department.Hope that helps!Good luck!
Chemistry help! have a FINAL tomorrow and im screwed! Please help!?
1. What is the mass of 2.22 mol (NH₄)₂S step: 2.22 mol (NH4)2S x(68.14 g (NH4)2S/ mol)= 151 g (NH4)2S 2. How many moles in 80.0g CH₄? step: 80.0 g CH4 x(mol/ 16.04 g CH4)= 4.99 mol CH4 6. Give the formula: nitrogen triflouride ANS: NF3 14. What is the oxidation #: Cr in Cr₂O₇^-2 step1: Cr2O7= ^2- (has an charge) step2: O=7(-2)= -14 step3: ask yourself, what mines 14 and = -2 Cr=2(6)= 12 12- 14= -2 15. What is the oxidation #: Mn in KMnO₄ step1: KMnO4=no charge ( 0 ) step2: K= 1+ O=4(-2)= -8 ,,, -8+ 1= -7 so Mn will be 7+ 7- 7= 0 (no charge) 35. What is the molarity of an unknown NaOH solution if it took 9.50 mL to titrate 10.00 mL of .175M HCl? step1: NaOH + HCl = NaCl + H2O step2: 0.01000 L x(0.175 mol HCl/ L ) x(mol NaOH/ mol HCl)= 0.00175 mol NaOH step3: 0.00175 mol/ 0.00950 L= 0.184 M hope these help...try to do the rest, it'll help you out for your final...have fun B.C
How many marks can I get on the NEET by solving the previous year’s AIPMT papers?
I you should read Ncert thoroughly for biology and chemistry ( Ncert + coaching class notes) , physics (pradeeps fundamentals of physics /whatever you prefer + coaching class notes). After this solving previous years question papers will be helpful in a way to get accustomed to the exam pattern and will learn to how to manage time during actual examination. Take mock tests regularly it will definitely help you to build up confidence.By doing this much sincerely can fetch you around 500+ easily.All the best.
Balancing symbol Equations?
Hiya x This is my science hw and Im so stuck! "In the Fractional Distillation Column, the "Napatha" Fracion is often used to make useful materials. This involves the cracking of hydrocarbons in the napatha fraction. For example: decane -> hexane + ethane Describe how cracking is carried out...." Also: "Why does ethene have different chemical properties from decane and hexane?" Thank you! Have a good new year! < :)