March 28, 2017

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Number of results: 39,315

Biology (Science)
Why is water a polar molecule? Please read: (Broken Link Removed) AND http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/chem/notes/chpt2/polar.htm
September 25, 2006 by Dakota

Please predict what will happen. Im not very good in chem. Iron metal and pb(NO3) Lead metal and Mg(9NO3)2 Copper metal and AL(NO3)3 Lead metal and AgNO3
April 18, 2013 by jim

what is a distribution coefficent?
September 8, 2007 by ~christina~

help with the chem lab. the molecular of a volatile liquid.
November 29, 2007 by Bmt

how many electrons can be contained in all orbitals with n=4??????
May 12, 2010 by Andy

what is the ph of 2.62 x 10 ^-2 M HBr solution? I get 5.94 is that right? thanks andy
May 23, 2010 by Andy

Advice...about chemistry degree Dr.Bob
Based on the question topic posted by Britney below titled:In your opinion (your answer to this reminded me of something) (I posted the same thing there but I thought it was improper to piggyback on that post so I posted this under a new topic) I don't know where to start but ...
March 25, 2008 by ~christina~

Dr bob, can you check my reply to chem question from andy thanx
May 10, 2010 by Andy

What is the conjugate acid of HC5H6O4-?? Is it HC5H6O42-?? thanks andy...
May 23, 2010 by Andy

science: ap chem
is NaH2CO3 soluble and separate into Na+ and H2CO3- ions?
April 19, 2010 by anonymous

science /chem
1250.37986 rounded to four significant figures is ??????
May 12, 2010 by Andy

Why do the d and f block elements have only 2 valence electrons?
February 21, 2011 by missy

chem- science - grd 11
okay so i have to prepare a procedure for the following experiment, except i have no clue what to do question- the science department had 5 different solutions but accidently lost thier labels. devise a procedure to help you determine which liquid is what? *hint- you may use ...
January 7, 2010 by just wondering

How many representative particles are in 2.5 mol H2O2? each mole consists of 6.02*10^23 things. Memorize that.
February 4, 2007 by Dennis

I need help finding information on how the conway microdiffusion is done/how it works. And why the sample is titrated. Thank you
September 12, 2008 by ~christina~

I need help finding information on how the conway microdiffusion is done/how it works. And why the sample is titrated. Thank you
September 13, 2008 by ~christina~

when the following equation is balanced , what is the sum of the co-efficients? AL2(SO4)^3+Ca(OH)2-->Al(OH)3+CaSO4
May 12, 2010 by Andy

Ka/Kb for the acetanilide being told that on the basis of this it will tell me whether a nitrogen or oxygen are protonated... (molecule: 4-bromoacetanilide) Thanks
April 7, 2008 by ~christina~

Sucrose, C12H22O11, is burned to produce carbon dioxide and water. What is the balanced formula and reaction type?
March 8, 2010 by Jacob

Science (Organic chem)
NO and NO2 are the nitrogen oxide gases being produced. Give the balance equation for both.
April 26, 2010 by Dana

Science (Organic chem)
What is the mechanism for the following: 1)KOH in alchohol phenanthrene-9,10-dione -------------> 2) H^+ 9-hydroxy-9H-fluorene-9-carboxylic acid
April 27, 2010 by Dana

what are the other practical applications of Analytcal chem on being a medical technologist?
November 26, 2014 by Arielle

can you please give me some practical applications of qualitative chem and quantitative chem...
November 26, 2014 by Kara

Science organic chem
why should you stop the reflux when the nitrogen dioxide (red gas) is no longer evolving? What is the concept of equilibrium?
April 27, 2010 by Dee

chem science
If a thermometer bulb is not completely immersed in water, what effect will this have on the measured melting point? Will it be higher or lower than actual?
October 12, 2014 by Sarah

chem- drbob222 please help
my original question was: how do i figure this out?? How much heat does your body lose when 2.46 g of sweat evaporates from your skin at 25°C? chem - DrBob222, Tuesday, February 22, 2011 at 10:52pm q = mass water x delta Hvaporization. chem - Rebekah, Wednesday, February 23, ...
February 23, 2011 by Rebekah

Balance the equation; ___Mg+__HCI->__MgCI2+__H2 How many moles of hydrogen gas are produced when 3.0 molesbof magnesium react?
January 24, 2013 by tyneisha

How many moles of sulfate ions are present in 1.2 mol of aluminum sulfate?
November 25, 2011 by roy

Science: Chem
How many milliliters of 0.10 M HCl must be added to 52.0 mL of 0.40 M HCl to give a final solution that has a molarity of 0.25 M?
November 1, 2011 by Lach

Science-AP Chem
Determine the volume (in mL) of 1.0 teaspoon. 1 tablespoon= 3 teaspoons; 1 tablespoon= ½ fluid ounce. Can you help me solve this?
September 2, 2015 by Zef

What is the structural formulae for the equation for the hydrolysis of lactose? It is impossible for us to draw structures on the computer. Here is a web site that may help you. http://www.rpi.edu/dept/chem-eng/Biotech-Environ/IMMOB/lactose.html
February 10, 2007 by Samantha

Chem 101 science
Rank the following samples in number of atoms from least to greatest. a) 2 mol of K atoms b) 48 g of S c) 27 g of Be d) 50 g of Na
August 26, 2010 by Samuel

Can you direct me to a site(s) which can help with college chemistry and statistics? Here are a couple of good chemistry sites that pretty well cover the waterfront. I don't know any stat sites but if you will repost with the subject line of "math" I'm sure someone will help ...
February 19, 2007 by jules

Concerning TLC plates... 1. why should't I allow the solvent to reach the top of the plate? (I assume it's the same as using paper like I did in gen chem but I'm not sure I know why it shouldn't be allowed to reach the top... what would happen?) 2. why sholdn't the spot sample...
September 27, 2007 by ~christina~

According to the reaction below,if 24 moles CO2 were produced,how many moles of C2H6 were reacted? 2C2H6+7O2 -> 4CO2+6H2O
January 24, 2013 by tyneisha

which of the following could not be reduced to a simpler piece of matter? compound, solution, element, mechanical mixture? Your exact answer is at the following site: http://www.syvum.com/cgi/online/serve.cgi/squizzes/chem/elements_compounds_mixtures.html
June 21, 2006 by jenna

another 12 chem Q. (science)
Q, What volume of 0.472 mol/L AgNO3 will precipitate the chloride ion in 40ml of 0.183 mol/L AlCl3? - Answer is 46.6ml, but how to solve this question?
February 4, 2009 by kite

science-gen chem
if 0.969 g of CaCl2 is mixed with 1.111 g of KlO3 how many grams of solid Ca(IO3)2 can theoretically be made? CaCl2(aq) + 2KlO3(aq) ===> 2Kcl(aq) + Ca(lO3)2 (s)
October 27, 2014 by christina

so i posted this question yesturday and got some help. which is the stuff below. can you look at the last thing i said which was the answer i got by doing what DrBob222 said to do and tell me if its correct.(the question is the first section) thanks chem - hannah, A salt ...
November 10, 2010 by hannah

chem chem
hi does anyone know what the VSPER theory is
June 16, 2016 by jake

What is the equation of the hydrolysis of lactose? http://www.rpi.edu/dept/chem-eng/Biotech-Environ/IMMOB/lactose.html
April 8, 2007 by laura

if a car produces 81g of {\rm CO_2}, how many grams of {\rm O_2} are used up in the reaction? the complete chem reaction is C2H6O+3O2--->2CO2+3H2O
October 19, 2012 by tracy

chemistry chem science
A portable CD player that draws 160 milliamperes of current is powered by Ni-Cd rechargable batteries. Compute the mass of Cd consumed when a disk is played for 35 minutes. (enter your answer in grams)
May 2, 2014 by luna

asprin (C9 H8 O4) is produced by the rection between salicylic acid (C7 H6 O3) and acetic anhydride(C4 H6 O3). Calculate the maximum mass of aspirin that can be obtained if you mix 50g of each of the reactants. The chem.equation for the reaction is as f.f C7 H6 O3(s) + C4 H6 ...
May 9, 2011 by allan

Chem Help!
I really need help with this question for my chem H.W. 1) On a summer day in Breckenridge, Colorado, the atmospheric pressure is 525 mm Hg. What is this air pressure in atmospheres? (round to the hundredths place) atm
April 10, 2008 by Lisa

Dr Bob Is it true that only TWO molecules of water are required to balance the equation for the reaction of HCL with Calcium Hydroxide.(calcium chloride is the other product....why??? Thanks andy
May 12, 2010 by Andy

The National Institute of Science and Technology (NIST) kinetics database lists the rate constant, k, of a particular gaseous reaction as 5.78× 10–10 cm3·molecule^–1·s^–1 at 298 K. Convert this constant, k, to torr^-1 X S^-1.
February 27, 2013 by Ann

science help chemisry
I am doing my study guide for chem test - I cant find a good understadable answer for these 3 1. What is your definition of electrolysis? 2. How do you separate pure substances? 3. My book says mayonnaise is homogenous; teacher told the class it was heterogenous??? HELP
October 4, 2009 by sam

Is nursing considered a a science major because I'm taking this course called "CHEM 1001 Chemistry and the World Around Us?" and I studying nursing in college. Please be honest. Thank you! :)
August 3, 2015 by Sam

Chem- bobpursley
What mass of protons would be required to just neutralize the charge of 1.5 g of electrons? my teacher said .0015kg times 1e-/.00091e-27kg times 1pt/1e- times 1.67262e-27 over 1 p chem - bobpursley, Tuesday, September 21, 2010 at 6:48pm That is what I would do also. But I ...
September 21, 2010 by Sara

Hund's rule states that each orbital in a sublevel will contain one electron before another electron will fill an orbital? Why?
February 21, 2011 by missy

the volume of a sample of gas is 650.ml at STP. what volumes will the sample occupy at 0.0degrees celsius and 950.torr??? is it 650.ml?
May 12, 2010 by Andy

chem - br bob is this right
What is the pH of a solution prepared by adding 4.000 grams of NaOH to a 50.00 mL of a buffer that is 2.00 molar both in acetic acid and sodium acetate? (Assume final volume is still 50.00 mL) * chem - DrBob222, Wednesday, April 21, 2010 at 10:52pm * chem - phil, Wednesday, ...
April 21, 2010 by phil

why do plastics have to be separated before recycled? Like different kinds of plastics are separated by why? Im on the organic chem unit right now.
April 8, 2010 by Lena

College science
Im in Chem. but looks like physics.. If a rock climber accidentally drops a 70.5 g piton from a height of 295 meters, what would its speed be just before striking the ground? Ignore the effects of air resistance.
February 1, 2014 by Max

What causes dispersion forces? Disperson forces are caused by an unsymettrical distribution of charge in the molecule, causing a net electric force. http://www.chem.purdue.edu/gchelp/liquids/disperse.html
January 9, 2007 by Dennis

Gen Chem II
Thanks for the information Dr. Bob. Would you be able to work it out so that I can actually see the steps with the numbers and follow from there. The question was on Vitamin K from Sunday at 2:44pm which you answered at 3:45pm. Thanks again. I am looking to get a tutor since I...
February 11, 2013 by Nefret

A secondary alcohol results from the attachment of a hydroxy group to which carbon atom? C | <---GIVEN STRUCTURE C1-C2-C3-C4 A) C1 B) C2 C)C3 D)C4 Answer is C! I have to explain why, but the teacher never taught us anything about organic chem. So please explain!
April 5, 2013 by Anonymous

The pKa of HEPES is 7.55 at 20C and it's MW is 238.31. Calculate the amounts of HEPES in grams and of 1.0M NaOH in ml that would be needed to make 300ml of 0.2M HEPES buffer at 7.2. I'm not sure how to go about doing this problem. Help please.
September 21, 2008 by ~christina~

science(chem) Dr.Bob Question from before
I'm doing an experiment and I'm supposed to have neutral basic and acid samples of solution. I just wanted to make sure that I knew which was which. (If I'm incorrect, please correct me) Acid: 0.7ml 10% H2SO4 + 0.7ml 10% Na2WO4(sodium tungstate) Basic: 0.7ml NaOH + saturated ...
September 20, 2008 by ~christina~

Dr.Bob222 Chem
I believe that you are correct because you have more experience in G-chem then I have. But how does doubling the reaction rate double the k value? Isn't k just a constant for a particular reaction?
February 1, 2013 by Devron

NaClO3 + H2O + HCl=> what form is the Cl in ? I know that a gas is formed but the reaction that I did also had Cl reacting with the reactants so I'm not sure in what form of Cl did my reactant react with the product of the above reaction. Thanks
April 6, 2008 by ~christina~

Science ap chem
For which of the following solutions must we consider the ionization of water when calculating the pH or pOH? (a) 3 × 10−8 M HNO3 (b) 0.10 g HCl in 1.0 L of solution (c) 0.00080 g NaOH in 0.50 L of solution (d) 1 × 10−7 M Ca(OH)2 (e) 0.0245 M KNO3
March 11, 2016 by Anonymous

chem org
dipole-dipole means? and diff between non polar and polar? is it really part of organic chem?
June 28, 2015 by jaydee

Chem 1
Write a chemical equation that shows how acid rain H2SO3 was produced from SO2 gas and water in a zip sealed bag? My chem. teacher never explained how to do this and I have several other questions on this type of subject. If you could help me out it would help me tremendously...
April 9, 2013 by Jess

physics vs. Chem
Doesnt physics seem to be harder than chem? Anyone?
October 24, 2010 by Kavi

Have to answer these in a reflection. Help? How has science evolved over time? How is human ingenuity portrayed in sciences? In what ways have humans shaped science? In what ways has science shaped our lives? What would the world be like without science? In what way has ...
January 14, 2014 by Rag

senior courses
this is a reply to Ms.Sue's question yesterday. my college and career goals are to do with Foods. cooking, culinary arts .. but i don't think that i can chose my next year (12th grade) courses according to that, can i? those are my plans for college right now i'm having ...
April 29, 2009 by y912f

Chem tutorial
Is there a good tutorial on how to read phase diagrams? Thanks from Sheryl I don't know how good this site is but it has a discussion as well as some questions (with hints) at the end. http://www.science.uwaterloo.ca/~cchieh/cact/c123/phasesdgm.html
November 12, 2006 by Sheryl

Determine the moles of aluminum acetate,AL(C2H3O2)3,that can be made if you do this reaction with 12 moles of acetic acid (C2H3O2H) C2H3O2H+AL(OH)3->AL(C2H3O2)3+3H2O
January 24, 2013 by tyneisha

sand bath (chem)
what are disadvantages and advantages of using a sand bath to heat something in chem?
October 21, 2007 by ~christina~

What is another name for cardamist? Please write the formula and a link to its structure. See http://antoine.frostburg.edu/chem/senese/101/consumer/faq/what-is-cardamist.shtml
September 4, 2005 by Nisar

Chem - DrBob222 & drwls
Just want to say thanks to you guys for the help you gave me during the last couple of months. It was all in preparation for the National Chemistry Test and I just received word I have been selected to be in the running for the National Chem Team. Thanks again.
October 8, 2007 by Vic

UV I was just wondering how a solvent would affect the spectra of a compound. Like a polar or nonpolar solvent for example: polar: Methylene chloride Nonpolar: cyclohexane, hexane, or ethanol Thanks
September 7, 2008 by ~christina~

Science, chem
Develop a method to prepare 100 ml of 0.500mol/l aqueous CuSO4x5H2O solution. Include the water molecules that are hydrated to the crystals as given in the molecular formula, in your calculation of the molar mass. show all your calculations. Prepare the solution.
September 8, 2015 by Jennifer

CHEM organic chem
i am really confused! i am doing the production of ethene from fractional distillation and i understand the whole concept of it what i don't get is how i can write a balanced eqn to show how ethene can be produced from C14H30 (tetradecane?!) i did C14H30 ------> C7H14 + ...
November 13, 2007 by AllyKat

CHEM organic chem
i am really confused! i am doing the production of ethene from fractional distillation and i understand the whole concept of it what i don't get is how i can write a balanced eqn to show how ethene can be produced from C14H30 (tetradecane?!) i did C14H30 ------> C7H14 + ...
November 13, 2007 by AllyKat

science chem
As a radio active material gets older, does it emit less, more or a constant level of radiation per second? There is less matter to convert, and it takes the same time per atom. Of course the activity is less.
April 1, 2007 by sean

Science (chem)
How would you make 300ml of a mixture of toluene and hexane in a ratio of 70:30 respectively? ~I really don't know how I would do this...would I do this?: xT + yH= 300ml xT= 300ml- yH then plug that in? That came out funny though since I get 0 in the end... ~Help Please~ Thanks
September 30, 2007 by ~christina~

chem equations
could someone tell me how i could solve this chem equation CH4 + NH3 +O2...> HCN +H20 AND USE THE LOWEST WHOLE NUMBER COEFFICIENT i WOULD BE GRATEFUL FOR ANY POINTERS Try these coefficients. 2,2,3==>2,6 Hi bex heres a little more help for you. Answer is 2CH4+2NH3+3O2--&...
May 6, 2007 by bex

chem grade 11
okay so i have to prepare a procedure for the following experiment, except i have no clue what to do question- the science department had 5 different solutions but accidently lost thier labels. devise a procedure to help you determine which liquid is what? *hint- you may use ...
January 7, 2010 by just wondering

chem grade 11
okay so i have to prepare a procedure for the following experiment, except i have no clue what to do question- the science department had 5 different solutions but accidently lost thier labels. devise a procedure to help you determine which liquid is what? *hint- you may use ...
January 7, 2010 by just wondering

chem grade 11
okay so i have to prepare a procedure for the following experiment, except i have no clue what to do question- the science department had 5 different solutions but accidently lost thier labels. devise a procedure to help you determine which liquid is what? *hint- you may use ...
January 7, 2010 by just wondering

I synthesized Nylon in my lab for organic chem. I need help figuring out the theoretical yield so I can compare it to my product that I synthesized. I looked up the reaction online on Google by typing in "Synthesis of adipoyl chloride and nylon 6.6." I clicked on the first ...
February 16, 2008 by ~christina~

How do I analyze a HPLC result? The lab tech injected the sample into the machine and I have the result paper for the sample injected which was caraway oil. However I'm not sure what to do with this now. It was recorded in volts per minutes. Thanks
November 3, 2007 by ~christina~

If I'm given 0.025 molar solution of Li2SO4(aq) and I have to find the concentration of each ion, how would I go about doing it? THANKS! My work (just li): 0.025M Li2SO4*(2MolLi/1MolLi2SO4)=.....Would that be right? I feel like there has to be one more step...How should I set ...
September 17, 2009 by Ally

Are: Ba(NO3)2, Ti)2, MgI2, and Ca(CH3COO)2 soluble or insoluble in H2O @ 25degrees C? Here is a site that lists the solubility rules. You should know this table; eventually you will want to know it so well that it is memorized. If you still have questions after viewing this ...
October 20, 2006 by K

I was just wondering if it was necessary to remember each branch of chemistry learned. I can't really remember general chemistry and I'm sort of loosing the organinc. I mostly remember the calculations and the starting part of each course, but other than that it's hazy. So, am...
July 26, 2008 by ~christina~

science chem
Please could someone give me a link to a site that explains waht an alkali is? thanks I don't know of a site BUT I probably can find one if you really want it. However, an alkali is simply a base such as NaOH or KOH, or lye. If you still want me to look for a site I shall be ...
March 19, 2007 by sam

science- pka- chem
Please verify that the pka of pyrrole is 6.04 and the pka of imidazole is 6.95. Why are they different? Doesn't pysrrole have one more bonded H in the ring structure than imidazole? I would expect slightly more acidic behavior just on the basis of this.
September 17, 2006 by ERB

Chem 101. Science
Rank the following samples in mass from least to greatest. a) 2 x 1023 S atoms b) 0.25 mol of Cu atoms c) 2 mol of N atoms d) 6 x 1023 Na atoms
August 26, 2010 by Samuel

science (chem)
I have a problem drawing this formula. CH3CH2CH2CH(CH3)CCCH3 The problem is the 2 c's next to each other. I don't know what that's supposed to look like since if it's 1 CH like with the bracketed CH3 it would be connected to that C but I'm confused as to how a carbon can be ...
August 31, 2007 by ~christina~

A piece of an aluminum can was cut into small pieces. Then 0.422 g of the chips from the can was used to prepare potassium alum according to the procedure we used. Calculate the theoretical yield (in g) of potassium alum that could be obtained in the reaction. (Alum MW=474.41 ...
November 24, 2014 by Caroline

chem help
im doing a graph for chem lab with excel. my classmate created a graph with these coordinates: X: 3.50 X10^-3 3.14X10^-3 3.28X10^-3 Y: -11.7 -8.96 -9.75 They got R2=0.998 but i got y = -3074.9x R² = 0.6291 why is it wrong. im desperate please help! screen shot of my graph: ...
October 23, 2010 by ben

Ok, so in my gen chem 1 class, the teacher showed us that ethanol would not dissolve a sugar cube while water dissolves a sugar cube easily. No explanation was given, she just told us we would find out in gen chem 2. Here i am in gen chem 2, and the same thing is shown to us ...
August 31, 2011 by Kevin

Hello, I just started my chem class today and I am totally stuck on this question: Hurriance Katrina had the 2nd lowest ever recorded barometric pressure at 0.920 mb. Convert this pressure to units of… a. atmospheres. b. Inches of Hg. I know i need to convert but I'm not ...
September 2, 2015 by Elizabeth

Using what you learned about science in your coursework thus far, discuss: 1. Why you think scientists probably want to leave what they do open to revision. 2. What are the hard-and-fast rules of science? Are there any? 3. With so few firm rules, how does science avoid ...
October 30, 2010 by ca

How many mg of fluorenone can 0.53mol of sodium borohyride(NaBH4) reduce? ~I don't know how to get this..wouldn't I have to have a reaction equation given to me?? Well I didn't have one for the question given to me so I don't know what to do. I tried looking for the reaction ...
October 7, 2007 by ~christina~

My lab teacher told me to leave my sample mixture of 2-bromobutane and 2-chlorobutane in a solution 1-2ml of sodium bicarbonate. Then I asked after I had wrapped it up, whether there would be a reaction if I left it there for a whole week since that's what I'm doing. He then ...
April 11, 2008 by ~christina~

A 10.0% by mass H2SO4(aq) solution has a density of 1.07 g·cm-3. How many milliliters of solution contain 8.34 g of H2SO4? What mass (in grams) of H2SO4 is in 248 mL of solution? It's been a while since I have had a chem class...so sorry if this seems really easy I just don't...
February 15, 2010 by Cairy

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