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April 17, 2014

Search: How many oxygen atoms are in 2.90g of quartz?

Number of results: 8,231

chemistry
a compound with the molecular weight of 276 grams was determined to be 39.10% carbon, 8.77% hydrogen, and 52.13% oxygen. what is the empiricial formula and the molecular formula for the compound? i do not know where to start!
Saturday, November 28, 2009 at 12:41pm by shelly

Chemistry
1. Write the equation and balance it. 2. Using the coefficients in the balanced equation, convert 5.27 moles ethane to moles oxygen. The arrow is made by ==> or --> Post your work if you get stuck.
Monday, January 18, 2010 at 9:36pm by DrBob222

Chemistry
Calculate the ratio of the effusion rate of oxygen gas (O2) to that of nitrogen gas (N2). Express your answer in decimal form and calculate your answer to at least four sig figs.
Thursday, September 23, 2010 at 11:17am by Mary

Chemistry
In a body of fresh water, a dissolved oxygen concentration of 0.262 or higher is usually needed to maintain a healthy aquatic ecosystem. For a lake to maintain this concentration, what is the maximum water temperature?
Thursday, February 24, 2011 at 2:39am by Amy

Chemistry
In a body of fresh water, a dissolved oxygen concentration of 0.262 or higher is usually needed to maintain a healthy aquatic ecosystem. For a lake to maintain this concentration, what is the maximum water temperature?
Thursday, February 24, 2011 at 2:43am by Amy

Chemistry
In a body of fresh water, a dissolved oxygen concentration of 0.262 or higher is usually needed to maintain a healthy aquatic ecosystem. For a lake to maintain this concentration, what is the maximum water temperature?
Thursday, February 24, 2011 at 2:43am by Amy

Chemistry
What is the volume of 150. mL of oxygen gas at 72.0°C and 110. mm Hg if the conditions are adjusted to 750. mm Hg and 82.5°C? Assume the amount of gas is held constant.
Thursday, April 14, 2011 at 3:48pm by Mary

Chemistry
When a mixture of 10.0 g of acetylene and 10.0 g of oxygen is ignited, a complete combustion of the reactants takes place. What is the limiting reagent of this reaction? How many grams of each of the reactants and products are present at the end of the reaction?
Monday, October 10, 2011 at 7:31pm by Destiny

chemistry
How much heat energy is given off when one kilogram of hydrogen gas at 25C and one atmosphere is combined with enough oxygen gas to make liquid water at 25C?
Friday, March 23, 2012 at 12:17am by Kevin

AP Chemistry
How many moles of butane do we need to produce 10 moles of CO2 by reaction with oxygen? I think the balanced equation is 2 C4H10 + 13 O2 -----> 8 CO2 + 10 H2O
Tuesday, April 30, 2013 at 7:54pm by Timofey

physics
A rigid tank contains 38:0 kg of O2 gas at a pressure of 9:70 atm. If the oxygen is replaced by helium, how many kilogram of helium will be needed to produce a pressure of 8:00 atm?
Monday, May 20, 2013 at 12:43pm by miya

chemistry
How many moles do you have in 25.0 g NBr3? That is 25.0/molar mass = ? How many molecules in that number of moles? Remember there are 6.02E23 molecules in a mole of anything Then multiply that by 3 since there are 3 atoms Br in each molecule of NBr3.
Sunday, February 19, 2012 at 9:12pm by DrBob222

Maths
Given that on average, an atom of gold weighs 3.27×10^−22grams, how much does an Avagadro’s number of gold atoms weigh (take Avagadro’s number to be 6.0221415×10^23).
Sunday, April 21, 2013 at 2:21am by Katie

science
How are the atoms of two different elements always similar to each other? A.They react in the same way. B.They have the same number of neutrons. C.Electrons and protons orbit the neutrons. D.Electrons orbit the nucleus.
Friday, January 24, 2014 at 10:43am by victoria

Chemistry
Could anybody simply explain how exactly Joseph Thomson discovered that atoms were not "indivisible" and that they were actually made of subatomic particles? (electrons) I've been having trouble understanding how exactly it happened, and everything on the internet seems to ...
Tuesday, February 12, 2008 at 8:36pm by Maddie

science
Those molecules containing carbon atoms are known as organic compounds. It's a vital part of life - especially when we talking about living organisms. Biological diversity has its molecular basis in carbon's ability to form a huge number of molecules with particular shapes and...
Wednesday, April 23, 2008 at 7:32pm by Jin

chemistry
It isn't H bonding; there are no H atoms and neither atom is N, O, F. I wouldn't think it's much of a dipole; Br is 2.96 and I 2.66 and that is only a small difference (but perhaps some dipole character). Both I and Br are large molecules with lots of electrons so I would go ...
Friday, September 28, 2012 at 10:50am by DrBob222

chemistry
Why is gas a chemical reaction not detectable by sight? Explain? my answer is because the atoms or molecules of matter in the gaseous state move freely among each other, and are, in most instances, packed more loosely than the molecules of the same substance in the solid or ...
Thursday, October 4, 2012 at 4:47pm by Lea

chemistry grade 12
Read over my earlier post to you. I mentioned that most beginning students made a mistake in not using the same number of atoms; therefore, "you should add a 2 in front of the HIO3." That way the I2 goes from a total of zero on the left to 2HIO3 or 10 total on the right.
Tuesday, November 17, 2009 at 4:29pm by DrBob222

chemistry
We can't draw pictures on the board. S is the central atom. Place 4 F atoms attached to S. Place 8 electrons around each F. Place a O= to S with four additional electrons around O. 40 electrons total.
Saturday, November 15, 2008 at 3:08pm by DrBob222

chemistry
Sterling silver, an alloy of silver and copper, contains 7.5 percent copper by mass and has a density of 10.3 g/cm3. How many copper atoms are in a sterling silver sphere whose radius is 2.0 in?
Monday, August 2, 2010 at 1:12pm by Joseph

Chemistry-Balancing Equations
Most of these just take a little practice. The more you practice the better you get. Here is what I do. First, I make sure to balance O2 LAST because since it is by itself I can put any number there I need. C7H60 + 02-> C02 + H20 Start with C. I see 7 on the left so I know ...
Tuesday, January 12, 2010 at 12:29am by DrBob222

science
when 1 gram of water evaporated the volume of the water vapor increases but the mass remains constant. why does the water remain constant i think because the number of atoms remain constant
Sunday, March 31, 2013 at 1:21pm by jeff

chemistry
It is next to impossible to draw Lewis dot structures on this board due to spacing problems. Put N on a piece of paper. Place three O atoms top, left, and right of the N. You have 24 electrons to add. Do them this way. To the top O, a pair of electrons on the left side, a pair...
Saturday, October 4, 2008 at 10:27pm by DrBob222

chemistry
Potassium nitrate is made by adding potassium chloride to hydrogen nitrate in the presence of oxygen gas. Along with the potassium nitrate, chlorine and water are produced. How would write the equation?
Sunday, February 26, 2012 at 1:49pm by mark

chemistry
Triple Point Clicker Challenge The Lewis structure for nitroglycerin is shown below. 1.00 mL of liquid nitroglycerin is placed in a sealed, reinforced, insulated steel box measuring 1.00 m on each side and filled with argon gas at 15.0 oC and 1.00 atm. The density of ...
Monday, November 10, 2008 at 4:42pm by james

chemistry
Ammonium nitrate decomposes explosively at high temperatures to form nitrogen, oxygen, and water vapor. 2NH4NO3-->2N2+4H2O+O2. Calculate the number of grams of water formed when 25 L of N2 is produced in this reaction (assume STP)
Monday, October 19, 2009 at 10:28pm by Meg

Chemisty
The value of ∆Ho for the reaction below is -1107 kJ: 2Ba(s) + O2(g) → 2BaO(s) How many kJ of heat are released when 15.75 g of Ba(s) reacts completely with oxygen to form BaO(s)? A) 35.1 B) 114 C) 70.3 D) 20.8 E) 63.5
Tuesday, September 17, 2013 at 1:22am by Jenny

Chemistry
N2(g) + O2(g) → N2O5(g) What volume of oxygen gas reacts to yield 750.0 cm3 of N2O5? The reaction conditions are 350°C and 2.50 atm pressure. I balanced the equation 2N2+2O2 = 2N2O5 BUT I AM NOT GETTING THE CORRECT ANSWER, WHAT AM I DOING WRONG?
Sunday, February 2, 2014 at 4:35pm by Harry

Chemistry
N2(g) + O2(g) → N2O5(g) What volume of oxygen gas reacts to yield 750.0 cm3 of N2O5? The reaction conditions are 350°C and 2.50 atm pressure. I balanced the equation 2N2+2O2 = 2N2O5 BUT I AM NOT GETTING THE CORRECT ANSWER, WHAT AM I DOING WRONG?
Sunday, February 2, 2014 at 4:35pm by Harry

chemistry please
or the compound: carbon in the middle with 3 bonds -double bond to oxygen -bond to Mn(CO)5 -bond to CH3 group is the oxidation state of the metal +1? d count 6? total electron count 20? coordination number 7?
Thursday, February 5, 2009 at 7:28pm by mary

Chem repost
or the compound: carbon in the middle with 3 bonds -double bond to oxygen -bond to Mn(CO)5 -bond to CH3 group is the oxidation state of the metal +1? d count 6? total electron count 20? coordination number 7?
Thursday, February 5, 2009 at 9:15pm by mary

chem post
or the compound: carbon in the middle with 3 bonds -double bond to oxygen -bond to Mn(CO)5 -bond to CH3 group is the oxidation state of the metal +1? d count 6? total electron count 20? coordination number 7?
Thursday, February 5, 2009 at 10:12pm by mary

chemistry
The boiling points of air (nitrogen and oxygen) molecules and water molecules are very different. The water molecules tend to stick to each other, so more energy (a higher temperature) is required to separate them and vaporize the liquid.
Thursday, February 18, 2010 at 9:06am by drwls

Chemistry
A sample of .234g of carbon is placed in a closed stainless steel bomb with .502g of of oxygen gas. The mixture is ignited giving of carbon dioxide. How many grams of carbon dioxide should be obtained upon combustion?
Sunday, February 21, 2010 at 1:36pm by Ben

Chemistry
An unknown compound contains carbon, hydrogen, and oxygen. When burned, a 2.000 gram sample of this compound releases 3.451 g of carbon dioxide and 1.059 grams of water. What is the empirical formula of this compound? Thank you very much.
Monday, October 17, 2011 at 9:21pm by Mom

Marine Science
Try here: http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla:en-US:official&hs=HiS&ei=qmb6SousLYu9ngf7pdnzDA&sa=X&oi=spell&resnum=0&ct=result&cd=1&ved=0CAYQBSgA&q=how+much+of+the+oxygen+we+breathe+is+produced+by+pytoplankton&spell=1 Sra
Tuesday, November 10, 2009 at 9:51pm by SraJMcGin

science
Mass is a measure of "amount". They mean the same thing. Therefore the relationship is linear. If you are referng the mass of one atom, or a fixed number (e.g. Avogadro's numbder) of atoms, then of course the "amount" (mass) is proportional to the mass of each atom
Wednesday, October 13, 2010 at 12:22pm by drwls

physics
How many moles of silver do you have? 8/147.87 for each mole of silver atoms, you have avagnumber*47 electrons. number electrons: charge/chargeof one electgron ratio=number added/109
Saturday, March 26, 2011 at 2:11pm by bobpursley

chem1 WORD PROBLEM!!
6. how many grams are in 4 moles of Be (OH)3? 7.How many atoms are in 4 moles of C6H12O6? 8.how many moles are in 12.04x10 23 to the power molecules of hamburgers? 9. how many molecules are in grams of Helium gas (He2)? hint:convert then moles then moecules
Thursday, December 6, 2012 at 6:51pm by tyneisha

chemistry
3. If sulfide ions are in the water going to the foil, there has to be a return path for negative charge to come back to the silver atoms. 4. Has to be in the liquid for sulfide ions to have a path. 5. NO scratches..No rubbing away of the silver.
Thursday, April 11, 2013 at 9:27pm by bobpursley

Science
I am learning how to balance a chemical equation but I don't understand it at all. I read that in order to balance the equation, you need to find the number of atoms. How do I do that? How do you balance a chemical equation?
Thursday, February 16, 2012 at 7:57pm by Michael

Check a chemistry answer
I don't understand why you went through the oxygen link; however, one factor canceled the other so no harm done except for extra work. The only error I see is the molar mass P2O5 should be 141.94 grams instead of 79.995.
Thursday, October 14, 2010 at 10:00pm by DrBob222

Chemistry
moles = grams/molar mass. moles (AH3)4(R2O3)4 = 55.8/478.17 = ?? moles x 6.022 x 10^23 molecules/mole = # molecules present. # R atoms is 8 x # molecules present.
Friday, October 15, 2010 at 1:49am by DrBob222

Chemistry
You did it correctly. The four (4) comes from the fact that there are four atoms to the unit cell; therefore, 4*mass of 1 atom = mass of the unit cell.
Saturday, May 14, 2011 at 11:29pm by DrBob222

grade 9 science
Noble gas atoms rarely react with other chemicals and form compounds. When they do, the resulting compounds are usually unstable and do not last. Some larger noble gases (specifically Krypton and Xenon) do form certain stable compounds.
Wednesday, March 18, 2009 at 2:11pm by Sean

Chemistry
I do it this way. First, do everything except the element of interest. Cu +2 6 O = -12 The only thing left is N. So for the N in the formula, we have -12+2 = -10; therefore, N must be +10 to make everything zero. There are 2 N atoms @ +10 total which makes each N = +5.
Wednesday, April 6, 2011 at 2:17pm by DrBob222

Chemistry
The chemistry? Silicon polymers do not have carbon, they have silicon atoms.
Thursday, April 4, 2013 at 4:03pm by bobpursley

last chem ?
Sodium is +1. O is -2 so the forumla for sodium oxide is Na2O. Actually, sodium + oxygen yields sodium PERoxide which is Na2O2 BUT I suspect sodium oxide may be the answer the prof is looking for. You must be the judge of that.
Wednesday, March 26, 2008 at 5:48pm by DrBob222

chem
Nitrogen(75.5 kPa), oxygen (19.2 kPa), carbon dioxide(0.05 kPa) and water vapor(4.3 kPa) are the usual atmospheric components. What is the total atmospheric pressure in kPa?
Sunday, March 30, 2008 at 5:25pm by joe

Chemistry
A gaseous mixture of and contains 30.8 nitrogen by mass. What is the partial pressure of oxygen in the mixture if the total pressure is 505mmHG ? I am getting .41 * (505/750)= .27 .27 is my answer, is this right.
Friday, September 26, 2008 at 5:49pm by George

Chemistry
With a platinum catalyst, ammonia will burn in oxygen to give nitric oxide, NO. 4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g) ÄH = -906 kJ What is the enthalpy change for the following reaction? NO(g) + 3/2 H2O(g) NH3(g) + 5/4 O2(g)
Saturday, October 18, 2008 at 10:36pm by Glenna

Chem Help
In body of fresh water, a dissolved oxygen concentration of 0.225 mM or higher is usually needed to maintain a healthy aquatic ecosystem. For a lake to maintain this concentration, what is the maximum water temperature?
Saturday, January 31, 2009 at 12:06pm by Sene

chemistry
I'm sure there are several problems but one must be the extreme reactivity of sodium. Sodium must be kept away from oxygen in almost any form and water (or water like materials such as alcohols).
Tuesday, October 12, 2010 at 1:53pm by DrBob222

Chemistry
balance the equation methane+oxygen>>carbon dioxide + water. then, how many moles of methane is in 32 grams? Then, use the mole ratio on the balanced equation coefficents to answer the questions.
Tuesday, November 9, 2010 at 7:24pm by bobpursley

Chemistry
using the balanced reaction equation for the combustion of propane, determine the number ofmoles of oxygen that would react with.50 mol propane and the number of moles of carbon dioxide that would be produced?
Sunday, January 9, 2011 at 7:57pm by Blake

chemistry
The activation energy for the reaction in which CO2 decomposes to CO and a free radical oxygen atom, O, has activation energy of 460 kJ mol^-2. The frequency factor is 2 x 1011 s^-1. What is the rate constant for this reaction at 298 K?
Sunday, March 20, 2011 at 7:57pm by Massiel

science please help!!!!!!
what best describes how wind mechanically weathers and erodes rocks and soils? a it causes water to evaporate b it transports particles c it transports oxygen d it causes water to expand my answer is b,am i right?
Thursday, September 1, 2011 at 6:42pm by LIDIA

chemistry
If the mass is 1.2 grams wouldn't it have a mass of 1.2 grams regardless of how much volume it occupies at STP (or any other set of conditions). Incidentally, I don't think 1.2 g oxygen will occupy 500 cc at STP.
Tuesday, September 27, 2011 at 11:34am by DrBob222

science
The density of liquid oxygen at its boiling point is 1.14 \rm{kg/L} , and its heat of vaporization is 213 \rm{kJ/kg} . How much energy in joules would be absorbed by 4.0 L of liquid ox
Monday, February 27, 2012 at 2:18pm by ashley

Chemistry
No. Oxygen is the most abundant element on earth with Si second and aluminum third. Helium is not in the top ten. The top ten are O Si Al Fe Ca Na K Mg H Ti
Tuesday, October 9, 2012 at 11:58pm by DrBob222

Chem Simple question
Magnesium metal burns in oxygen to form magnesium oxide, MgO. (a) Write a balanced equation for the reaction Why is it 2Mg+O2->2MgO and not Mg+O->MgO
Sunday, September 29, 2013 at 5:28pm by Julie

CHEMISTRY
The oxidation number of oxygen is always -2. Therefore (2×Cl) + (-2×7) = 0, and so Cl = 7, i.e. the oxidation number of chlorine = 7
Tuesday, November 20, 2007 at 8:47pm by Anonymous

SCIENCE
science concept map!! test tubes matter oxygen please please please please HELP!!
Friday, February 1, 2008 at 1:54am by Jenna

science
This is a science question so be prepared. lol How many orbitals does hydrogen (H) have? 1 or 2 or 3 How many orbitals does oxygen (O) have? 1 or 2 or 3
Monday, February 25, 2008 at 10:56pm by JAKE

chemistry
percent O in H2O = (mass O/mass H2O)*100 %Oxygen = (16/18)*100 = ??
Monday, February 15, 2010 at 10:42pm by DrBob222

chemistry
sodium chloride+water+ethanol+oxygen+carbon dioxide+water+sodium chloride=
Friday, February 18, 2011 at 3:49am by towela

math
What is the figure that gives the half-life of the isotope in minutes to 4 significant figures? Exponential regression on a set of data, which gives the amount of atoms of a radioactive isotope remaining after a time X minutes, produced the following output. ExpReg y = a*b^x a...
Friday, May 18, 2007 at 8:01am by claudia

chemistry
using data in table 6.5, calculate the densities of (spherical) atoms of potassium and calcium and compare to the listed densitites of these metals K=39.10 amu, .231 nm (atomic radius) Ca= 40.08 amu, .197nm (atomic radius)
Thursday, October 27, 2011 at 6:55pm by trish

physics
I don't see a question here. In any balanced chemical reaction, the number of atoms of each element present is the same on the reactant and product sides. Furthermore, the mass of each atom is unchanged by the reaction. The total number of electrons also does not change. ...
Friday, March 2, 2012 at 3:44am by drwls

chemistry
a chemical analysis that silicon crystal weighing 100 gm containing 16.5 mg of aluminium which is substitutionally incorporated (the aluminium atoms replaced some of the silicon atom) what is the number of extrinsic charge carriers in this crystals? answer in carriers/cm3
Sunday, April 28, 2013 at 2:51am by himani

8th Grade Earth Science Help?
Which of the following terms refers to the time it takes for one-half of the radioactive atoms in a sample of a radioactive element to decay? - relative age - absolute age - potassium-argon data - half-life** Is my answer correct?
Tuesday, January 14, 2014 at 7:05pm by Rainshine

AP Biology
Explain why if you leave a glass of cold tap water on the counter on a warm day bubbles will appear along the interior of the glass. I think it has something to do with the amount of dissolved oxygen that can be held in the water versus the hot air.
Thursday, October 2, 2008 at 10:40pm by Billy

Chemistry
Oxygen gas reacts with powdered aluminum according to the following reaction: 4Al(s)+3 O2(g) --> 2 Al2O3 (s) How many liters of O2 gas, measured at 789 mm Hg and 35 C, are required to completely react with 2.2 mol of Al?
Friday, April 16, 2010 at 3:39pm by Eileen

chem
Did you do the experiment with KClO3.What happened to the oxygen? Le Chatelier's Principle, stated a little differently than the esoteric manner in which it is portrayed in texts, is this: When a system in equilibrium is subjected to a stress,the reaction will try to undo what...
Wednesday, February 1, 2012 at 9:26pm by DrBob222

Science
Which answer best describes the purpose of the muscles in the human body? A)to protect tissues and form blood B)to remove and use nutrients from food C)to produce movement and provide support D)to combine blood and oxygen needed for movement
Tuesday, April 10, 2012 at 9:15pm by Sally urgenttt

chem
Maleic acid is an organic compound composed of 41.39% C, 3.47% H, and the rest oxygen. If 0.250 mol of maleic acid has a mass of 29.0 g, what are the empirical and molecular formulas of maleic acid?
Monday, June 28, 2010 at 11:19pm by casi

Chemistry
Fungal laccase, a blue protein found in wood-rotting fungi, is 0.390% Cu by mass. If a fungal laccase molecule contains four copper atoms, what is the molar mass of fungal laccase?
Saturday, September 11, 2010 at 5:54pm by Melissa

Chemistry
Compounds that have no formal charge usually are the preferred ones but if a formal charge is necessary we strive for the lower numbers; i.e., a formal charge of +1 on one atom and a -1 on another is better than +4 on one and -3 and -1 on two other atoms.
Sunday, November 27, 2011 at 11:59pm by DrBob222

chemistry
This is ok but you omitted the double bond in CH2=CHCH2CH3. The double bond needs to be there (even though it's a condensed formula). When it's omitted the observer doesn't know if it is a double bond or if you just forget and left out the two H atoms.
Tuesday, February 14, 2012 at 10:12pm by DrBob222

Chemistry
It would be better and more conventionally written as (CH3)3CCH2CH2CH3 the longest continuous chain of C atoms is 5, from the CH3 on the LHS to the CH3 on the RHS. Much easier if you make a model, plasticine and used matches work well if you cdon't have models. So it is a ...
Tuesday, January 26, 2010 at 9:47am by Dr Russ

math
what is the number of each atom in the unit cell of a BCC cystalline structure unit cell. I know its 2 atoms=8/8 +1 Calculate what % of each atom is contained within the unit cell? How do I do this
Wednesday, January 13, 2010 at 10:46pm by Anonymous

science
Matter is anything that has mass and occupies space. What is mass? Anything that opposes a change in motion. examples of matter: atoms, molecules, electrons, protons, neutrons, positrions (actually this is called anti-matter, a form of matter).
Monday, September 17, 2007 at 4:05am by bobpursley

AP Chemistry
Iron has a density of 7.86 g/cm3 and crystallines in a body-centered cubic lattice. Show that only 68% of a body-centered lattice is actually occupied by atoms, and determine the atomic radius of iron.
Saturday, November 14, 2009 at 11:50am by Angie

Chemistry
I would convert 56 g CO2 to moles, convert 9.03E23 atoms to moles, then find mole fraction Ar which will be n argon/total n = XAr. Then pAr = XAr x total P. Don't forget that you hav 3.04 mol CO.
Saturday, January 14, 2012 at 9:25pm by DrBob222

AP Chemistry
iron has a density of 7.86 g/cm3 and crystallizes a body centered cubic lattice. Show that only 68% of a body centered lattice is actually occupied by atoms, and determine the atomic radius of iron
Tuesday, November 27, 2012 at 8:40pm by Shayla

science
Never found in nature uncombined? Alkali metals Alkaline Earth Metals Boron Family Carbon Family Nitrogen Family Oxygen Family Halogen Family Noble Gases
Wednesday, November 7, 2007 at 1:01am by liz

Electrochemistry
How much electric charge is needed to produce 1.000kg of Na metal from the Na+ ions in NaCl? You need one electron per atom. How many atoms are present in 1kg of Na? Use avagradros number. To change to coulombs, remember that 1 electron= 1.6E-19C
Thursday, May 17, 2007 at 10:59am by Jerry

math
Very silly question, but .... amount = 1(1.2)^1200 = 1.041 x 10^95 that is 1041000000....0000 for 96 digits (we don't even have "names" for a number like this. There is nothing measureable requiring that number. The number of atoms in our visible universe is estimated at 10^85...
Thursday, January 12, 2012 at 8:42pm by Reiny

Chemistry
Functional groups 1. are the repeating unit of polymers. 2. are groups of atoms whose chemical prop- erties are pretty much independent of their chemical environment. 3. perform specific biological functions using molecular recognition. 4. are a fictitious concept like ...
Thursday, April 21, 2011 at 11:17pm by Bob

chemistry
What is the percent by mass of H in ethyl alcohol (C2H6O)? The molecular weight of carbon is 12.0107 g/mol, of hydrogen 1.00794 g/mol, and of oxygen 15.9994 g/mol. Answer in units of % Your answer must be within ± 0.1%
Sunday, January 29, 2012 at 7:44pm by tyeisha colley

science cells
Try some of the following links for information: 1. http://search.yahoo.com/search?fr=mcafee&p=do+animal+cells+h+ave+cell+walls%3F 2. http://search.yahoo.com/search?fr=mcafee&p=can+water+%26+oxygen+pass+through+the+cell+wall%3F Sra
Thursday, October 6, 2011 at 2:24pm by SraJMcGin

AP Chem
By the way, I made an error in the problem below. There are TWO atoms per unit cell for the body centered cubic structure; therefore, the mass of a single atom is TWICE 47.88*(1/6.022 x 10^23) etc. In cubic closest packing the volume occupied is about 74%.
Tuesday, January 1, 2008 at 7:25pm by DrBob222

Chemistry
Na has a +1 charge because its in the first group of the periodic table. For the CO3, didn't the teacher give you a sheet of common ions that tells you what the charges are? That was what my teacher did. But if you don't have the sheet, I THINK the reason why it has a -2 ...
Saturday, March 7, 2009 at 2:43pm by Chopsticks

Science
Hello van some one show me how to draw a dot and cross diagramm for 1 lithium atom and 1 fluorine atom(Lif) and also a diagram for 1 magnesium atom and 1 oxygen atom (MgO) Thankyou Paul.
Monday, March 28, 2011 at 4:07am by Paul

Science 7R - HW Qs. Check (PLZ read!)
What is the difference between aerobic and anaerobic organisms? My Answer: Aerobic requires oxygen, anaerobic doesn't. Is my answer to this question is correct. Please reply this post! Thank You!
Thursday, February 2, 2012 at 8:20pm by Laruen

Chemistry
Calcium carbonate decomposes on heating producing potassium nitrate and oxygen. Write a balanced equation for this reaction. Heating 100g of pure potasium nitrae what mass of potassium nitrate would be produced?
Wednesday, March 21, 2012 at 6:32pm by JOJO

AP CHEMISTRY!!!!
Carbon monoxide reacts with oxygen to form carbon dioxide by the following reaction: 2 CO(g) + O2(g) → 2 CO2(g) ∆H for this reaction is −566 kJ/mol rxn. What is the ∆H for CO(g)?
Thursday, October 18, 2012 at 8:47pm by Joe King

Chemistry
Assume that some of the magnesium nitride is not completely converted to magnesium hydroxide and subsequently to magnesium oxide. Will your empirical formula be too high in magnesium or too high in oxygen? Please show any calculations you used to determine your answer.
Saturday, February 15, 2014 at 10:08am by Liliah

Chemistry
How many Mg WHAT? g Mg = 32*0.0045 = ? mols Mg = ?g Mg/atomic mass Mg = y #atoms Mg = y mols Mg*6.02E23 = ??
Wednesday, October 9, 2013 at 4:14pm by DrBob222

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