Are there any chem whizzes in here who can help me with these few problems?? I've been staring at them for the past 2 hours and still haven't been able to come up with anything :( Any help would mean a lot to me. Write the correctly balanced formula equations; don't give states, but don't forget the diatomic elements: 1. Name Equation: ammonium iodide + magnesium hydroxide --> magnesium iodide + ammonia + water Formula Equation: 2. Name Equation: potassium + copper(II) nitrate --> potassium nitrate + copper Formula Equation: Show your numerical set-up, including units, and give the answer with its units and the proper number of significant figures: 1. A gallon of pure carbon dioxide gas contains 1.0 x 10^23 molecules of CO2. How many moles of gas is this? (I know it has something to do with avagadro's number) 2. How many phosphoric acid molecules, H3PO4, are in 45.7 g of it? 3. What is the mass of 5.50 billion water molecules? Gosh I hate chem -cry2
1) 2NH4I+Mg(OH)2 ---> MgI2+2NH3+2H2O 2) 2K+Cu(NO3)2 ---> 2KNO3+CU I'm not sure if i did the second formula equation correctly and for the moles questions.....im learning that in chem right now also and im not getting it >.<
Do you know when she will be online? Thanks don!!! Do you mind telling me how you got those answers? -sweat (this is what happens when you miss ONE day of lecture :()
2. How many phosphoric acid molecules, H3PO4, are in 45.7 g of it? 45.7g H3PO4 x (1mol H3PO4)/(98.0g H3PO4) x (6.02x10^23 H3PO4 molecules)/1mol H3PO4 = 2.81x10^23 molecules H3PO4 3. What is the mass of 5.50 billion water molecules? (5.50x10^9 H2O molecules) x (1mol H2O)/(6.02x10^23 H2O molecules) x (18.0g H2O)/(1mol H2O) = 1.64x10^-13 g H2O i hope i did number 3 right...
ammonium iodide + magnesium hydroxide --> magnesium iodide + ammonia + water first you have to translate then balance so...ammonium iodide = NH4I magnesium hydroxide = Mg(OH)2 magnesium iodide = MgI2 ammonia = NH3 water = H2O which gives you.... NH4I+Mg(OH)2 ---> MgI2+NH3+H2O then you balance it........2NH4I+Mg(OH)2 ---> MgI2+2NH3+2H2O
OMG, you guys are awesome! Thanks for the help! One more thing -sweat Do you guys know how to write the electron configurations? How would you write it for the 118th element? I get confused about the sublevels and our quiz on it is like next week >.< I don't even know why I signed up for AP chem...
1. A gallon of pure carbon dioxide gas contains 1.0 x 10^23 molecules of CO2. How many moles of gas is this? hmm, i know that 1 mole of a gas takes up 22.4 litres, but iono about gallons... *checks calculator*.... 4.927311162 gallons. huh.... so i guess its: 1.0x10^23 molecules CO2 x (1mol CO2)/(6.02x10^23 molecules CO2) x (4.93gal CO2)/(1mol CO2) = 0.82 mol CO2 but again, im not sure considering im not familiar with gallons.
This one's actually really simple. You know that a mole consists of Avagadro's # of objects (atoms/molecules), so all you have to do is divide 1.0 x 10^23 molecules of CO2 by Avagadro's #. The conversion factor you should use to setup a problem like this is either 6.02 X 10^23 objects/1 mole or 1 mole/6.02 X 10^23 objects. So start with the given (1.0 x 10^23 molecules of CO2) over 1 and mulitply it by 1 mole over avagadro's #, and that will give you the answer. It should look like this: don and ms-jojo have all the other problems correct Excuse me?
I wonder which person in this thread at this moment was laughing at my hydrogen joke. I'm doing good actually (I know you are just hoping for me to fail ). Can't say the same for Calc though.
Thanks so much guys! You don't know how much this means to me! Managed to get an 81% on my quiz today lol. Now if I could just get some help on a few more problems -sweat We're learning Gas Laws and Stoichiometry of Gases now :( Show your numerical set-up, including units, and give the answer with its units and proper # significant figures. Periodic table molar masses should use atomic weight to 2 decimal places. Use Avagadro's # factor if the "number of particles" is involved. 1. An open empty metal paint-thinner can under 1.00 atm pressure is heated to 712 degrees C over a flame, then is capped air-tight and allowed to cool back down to 22.0 degrees C. Find the new pressure inside the can before it collapses. Use this balanced equation for the next problems: N2 (g) + 3H2 (g) -> 2NH3 (g) (if no P, V, & T, assume STP) 1. Find the volume of hydrogen needed to produce exactly a trillion molecules of ammonia. 2. Find the volume of ammonia that will be produced at 727 torr and 25 degress C from 42 g of nitrogen.
OMG! so much numbers! By the way, in chem, do you have to remember all the freaking elements and stuff? -shock
again, there is a big chance i am wrong.. 1. Find the volume of hydrogen needed to produce exactly a trillion molecules of ammonia. 1x10^12 molecules NH3 x (1mol NH3)/(6.02x10^23 molecules NH3) x (3mol H2)/(2mol NH3) x (22.4L H2)/(1mol H2) = 5.58x10^-11 L H2 but i only know in litres. ><
volume is constant P1 = 1 atm ; T1 = 712°C T2 = 22°C P2 = P1/T1 x T2 = 1 atm / 985 K x 295 K = 0,2995 atm = 30,35 Pa N2 (g) + 3H2 (g) -> 2NH3 (g) mol (N2) : mol (H2) : mol (NH3) = 1 : 3 : 2 2. Volume of Nitrogen --> using PV = nRT, n = m/M Volume of Nitrogen = (42 g x 8.314 J · K-1 · mol-1 x 298 K) : (133.322 Pa x 28 g/mol) = 26 m^3 Volume of Amonia = 3 x Volume of Nitrogen = 78 m^3 I hope it's correct
Wow! I have already forgotten most of my chem. Never thought about asking homework questions on here. Maybe I should see if people can solve my engineering problems.
ms-jojo and takochan...you guys both have different answers for #1 >.<. I'm also a bit confused on how you set up the last problem, takochan. The steps look confusing... :( I understand the first one though All in all, thanks for both your help! The paper isn't due 'till Friday, so I still have 2 more days to complete it. If I somehow manage to figure out the answers I'll post them up here.
