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October 1, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry
Calculate the percentage by mass for Carbon in C2H2
Wednesday, September 3, 2014 at 12:46am

Chemistry
When a 1.1 gram ice cube is placed into a 10.0 mL graduated cylinder, the level of water inside the graduated cylinder raises 1.20 mL. What is the Density of the ice cube? My Work: Density = 1.1g/10.0 mL + 1.20 mL? my answer came out to be; Density= .0982 g/mL
Wednesday, September 3, 2014 at 12:17am

Chemistry(Please help)
For a carbon atom that is sp2 hybridized, I understand that the electron configuration would be Yes, 1s2 2s1 2p3 which is a 2s up arrow,and 3 orbtials that are 2p up arrows but then since the four bonds hybridize to form four sp3 hybrid bonds how do I write this? Also for an ...
Tuesday, September 2, 2014 at 11:33pm

Chemistry
Question: how do you dilute something with a huge concentration to the same thing with a smaller concentration? For example: How do you dilute a 36 M solution of NaOH to a 6 M solution of NaOH?
Tuesday, September 2, 2014 at 10:26pm

Chemistry
Analytical Chemistry question: Find the pH and the concentration of each species of lysine in a solution of 0.0010 M lysine*HCL. I know that the pKAs of lysine are (1.77)(CO2H) 9.07 (-NH3) 10.82 ( -NH3) but I am not sure where to go from there.
Tuesday, September 2, 2014 at 9:58pm

Chemistry
How many moles of chlorine atoms are present in 4.8x10^20 molecules of carbon tetrachloride?
Tuesday, September 2, 2014 at 9:47pm

chemistry
Which of the following statements correctly describes energy levels? A. Electrons can never move to a higher or lower energy level. B. In its outermost energy level, oxygen has 4 valence electrons C. The second energy level holds a maximum of eight electrons. D. The greater ...
Tuesday, September 2, 2014 at 9:27pm

Chemistry
What is the osmotic pressure of a solution made from dissolving 60.0g of glucose, C6H12O6, in 450 mL of water at 10.0∘C?
Tuesday, September 2, 2014 at 8:42pm

Chemistry
Suggest why calcium compound produce a coloured flame but magnesium do not?
Tuesday, September 2, 2014 at 8:36pm

chemistry
calculate the mass of a 4.50 m long copper rod that has the diameter of 1.25cm. the density of copper is 8.94 g/ml
Tuesday, September 2, 2014 at 6:40pm

chemistry
calculate the mass of a 4.50 m long copper rod that has the diameter of 1.25cm. the density of copper is 8.94 g/ml
Tuesday, September 2, 2014 at 6:40pm

chemistry
We did not find any results for 'if the solubility of cuso4.5H2O at 30 degree celcus is 25 gram per 100gram of H2O.what is the maximum mass of crystal that will be obtained from 10gram?
Tuesday, September 2, 2014 at 4:19pm

chemistry
medicine you would find in your house?
Tuesday, September 2, 2014 at 3:46pm

chemistry
Suppose you have two 100-mL graduated cylinders. In each cylinder there is 40.0mL of water. You also have two cubes: one is lead(11.3g/ml), and the other is aluminum(2.70g/ml) Each cube measures 2.0cm on each side. After you carefully lower each cube into the water of the ...
Tuesday, September 2, 2014 at 2:11pm

chemistry
2) Calculate the following properties of 2,4,6-trichlorophenol (C6H3Cl3O) at 25ºC: - Diffusion coefficient in water (cm2/s) - Henry’s constant [(atm·m3)/mol] - Henry’s constant (dimensionless) Given information: - Universal gas constant (R) = 0.082 atm&...
Tuesday, September 2, 2014 at 9:14am

Chemistry
When 62.1 moles of calcium acetate are dissolved in enough water to make 585.1 milliliters of solution, what is the molarity of acetate ions? Answer in units of M
Monday, September 1, 2014 at 11:32pm

chemistry
how many mL or .0252M HNO3 are required to neutralize 25.00mL of .0148M of Sr(OH)2? and how did you get the answer!!!
Monday, September 1, 2014 at 9:47pm

Chemistry
Fannie eats a dozen doughnuts every 36 hours. How many doughnut does she eat in a week? I used Dimensional Analysis(which isn't helping at all), but it keeps giving me weird number, like 36 over 2016 or 252 over 2016.
Monday, September 1, 2014 at 9:13pm

chemistry
Block A of an unknown metal has a volume of 125 cm3. Block B of a different metal has a volume of 145 cm3. If block A has a greater mass than block B, what can be said of the relative densities of the two metals? (Assume that both blocks are solid.)
Monday, September 1, 2014 at 7:53pm

chemistry
1.15g of acetylsalicylic ia recovered from an aspirim synthesis reaction that began with 2g of salicylic acid, what would be the percentage yield for the preparation? show your computations
Monday, September 1, 2014 at 6:08pm

chemistry
Show calculations for how you will prepare 250 mL of 0.1 M AgNO3 solution from solid AgNO3 and water Give the reagent amounts and units.
Monday, September 1, 2014 at 4:23pm

Writing
Please give me a score of 1-6 (one being poor and six being excellent). Also, please give me some feedback! Thank you in advance! Essay prompt: What motivates people to change? Essay: Many people know that eating junk food is unhealthy. Yet, they keep eating it because it ...
Monday, September 1, 2014 at 1:13pm

chemistry
bottle of hcl which is 40 mass%and has density of 1.20g /ml. calculate ml to be taken from this bottle to prepare 500 ml solution of 0.2 M
Monday, September 1, 2014 at 10:21am

Chemistry
I am having trouble figuring out the electron configuration for a carbon atom when it is in a molecule such as methane. I know that the ground state configuration for carbon is 1s2 2s2 2p2 but im not sure how to figure it out when it is bonded to other atoms. Thank you for the...
Monday, September 1, 2014 at 12:43am

chemistry
a solution of oh negative ions is added to a beaker of pure water 25 degrees celcius to a final concentration of 137 nM calculate the ph of the solution
Sunday, August 31, 2014 at 6:52pm

chemistry
a solution of oh negative ions is added to a beaker of pure water 25 degrees celcius to a final concentration of 137 nM calculate the ph of the solution
Sunday, August 31, 2014 at 6:52pm

Chemistry
Hey, So a runner wants to run 10.0 km. She knows that her running pace is 7.5 m per hour. How many minutes must she run? Can you explain it?
Sunday, August 31, 2014 at 5:06pm

chemistry
Ethanol glycol has a density of 1.11 g/cm^3. What is the volume in L of 4.1 kg of this liquid?
Sunday, August 31, 2014 at 4:21pm

Chemistry
Suppose that the dot/area representing the longest wavelength of color in this situation was located 21 mm from the baseline, and the dot/area representing the shortest wavelength of color was located 36 mm from the baseline (see Figure 9.4 on page 288 for help). If the ...
Sunday, August 31, 2014 at 2:45pm

chemistry
How do you convert 3.345 kJ to mJ?
Sunday, August 31, 2014 at 11:20am

Chemistry
If 567mL of water are added to a flask which already contains 1.440 L, what is the new volume of water in the flask? My work: 1.400L=1440mL 567mL=0.567L
Sunday, August 31, 2014 at 8:05am

Chemistry
I am unsure how to write hypotheses for my experiments for pH, salinity using tirration(agno3), turbidity, conductivity of water samples. The teacher wants the hypothesis in this format Hypothesis format - If (relationship between independent variable and dependent variable) ...
Sunday, August 31, 2014 at 7:38am

Chemistry
What is the pH of a solution prepared by dissolving 1.23g of 2-nitrophenol (FM 139.11) in 0.250 L? Well so, i calculated the no.moles of 2-nitrophenol, and divided it by 0.250, to get the molarity which was 3.53E-2. Since the molar ratio of dissociation is 1:1, i assumed [H+] ...
Sunday, August 31, 2014 at 7:28am

chemistry calculations
The following equilibrium partial pressures were measured at 750 deg C. PH2=0.387atm,PCO2=0.152atm,PCO= 0.180 atm,and PH2O=0.252atm. What is the value of the equilibrium constant Kp for the reaction? H2+CO2 ====CO+H2O
Saturday, August 30, 2014 at 11:24pm

chemistry calculations
At 25 deg C, Kc is 5.84x10-3 for the dissociation of dinitrogen tetraoxide to nitrogen dioxide. N2O4(g) ==== 2NO2(g) a) Calculate the equilibrium concentration of both gases when 4.00 grams of N2O4 is placed at 2.00-liter flask at 25 deg C. b) What will be the new equilibrium ...
Saturday, August 30, 2014 at 11:20pm

chemistry calculations
At some temperature,the reaction PCl3(g) +Cl2(g) ====PCl5(g) is at equilibrium when the concentration of PCl3, Cl2, and PCl5 are 10, 9.0, and 12mol/L, respectively. Calculate the value of Kc for this reaction at that temperature.
Saturday, August 30, 2014 at 11:16pm

Chemistry
Given this equation. C3H8 + 5O2 -> CO2 + H2O. How many moles of O2 will be needed to comepletely burn 1.75 moles of propane C3H8?
Saturday, August 30, 2014 at 9:14pm

chemistry
How would you convert 77 degrees F to kelvins? Can you explain it please because I don't really understand how to get it to Fahrenheit.
Saturday, August 30, 2014 at 7:34pm

Chemistry Science
calculate the mass of carbon dioxide that would be produced when one gas of tank of gasoline (use octane) is burned in the air. assume an 80 liter gas tank and 0.703 g/ml as the density of octane
Saturday, August 30, 2014 at 12:35pm

chemistry
A student has repeated the hydrolysis experiment with 2-iodo-2-methylpropane as the alkyl halide and found that the time to colour change was too fast to measure easily. Suggest two ways in which the reaction could be slowed down and by what process the slowing is happening in...
Saturday, August 30, 2014 at 8:26am

chemistry
A first order reaction and a separate second order reaction both have the same rate of reaction. What is the effect on the rate of reaction for each reaction if the concentrations of reactants in both reactions are halved?
Saturday, August 30, 2014 at 7:50am

chemistry
Gallium is a metal with a wide variety of uses. Some of its applications include computer memory chips, light emitting diodes and lasers. Radioactive isotopes of gallium are used to image the human body and locate tumors. Naturally occurring gallium consists of two isotopes. ...
Friday, August 29, 2014 at 8:40pm

Chemistry
Write the ionic equation for the reaction of lead 2 nitrate reacting with the acidic solution to form a precipitate
Friday, August 29, 2014 at 5:54pm

chemistry
In the combustion of hydrogen gas, hydrogen reacts with oxygen from the air to form water vapor. If you burn 54.8 g of hydrogen and produce 4.90 × 102 g of water, how much oxygen reacted?
Friday, August 29, 2014 at 5:11pm

Chemistry
How many moles of aspirin C9H8O4, are in a bottle comtaining 450g by weight? (The approx atomic weights are C=12, H=1, O=16)
Friday, August 29, 2014 at 11:34am

Chemistry
How many moles of sodium ions are there in 5.85g NaCl? So far all I have tried to do is 5.85/58.5=0.1 mol of NaCl but I don't understand how you find the number of moles of sodium ions only.
Friday, August 29, 2014 at 8:12am

Chemistry
The level of water in a rectangular swimming pool needs to be lowered 4.00 inches. If the pool is 36.50 ft long and 15.00 ft wide, and the water is siphoned out at a rate of 5.0 gal/min, how long will the siphoning take? 1 ft^3 = 7.48 gal.
Thursday, August 28, 2014 at 6:44pm

chemistry
Please I need help. Many,but not all, compounds are made up of positive and negative ions. Three positive ions A^+, B^2+ and C^3+ could form a total of six different compounds with negative ions, Y^2- and Z^3-. Derive the formulae for six compounds and write them in the table.
Thursday, August 28, 2014 at 5:03am

Chemistry
You want to know if the amount of protein in a female rat’s diet affects the average birth weight of her individual offspring. In a controlled experiment, what would be the dependent (responding) variable? a) amount of protein in the diet b) average birth weight of ...
Wednesday, August 27, 2014 at 8:55pm

Chemistry
Dr. Penny Dollar is a health psychologist interested in getting more people to wash their hands after using the restroom. She places a stack of attractive terry cloth towels in one men’s room and a roll of brown, thin paper sheets in another men’s room in the same ...
Wednesday, August 27, 2014 at 8:54pm

chemistry
You have a protein solution of 3.7mgs/ml You need to load 20ug onto a gel. How much of this solution would you use ?
Wednesday, August 27, 2014 at 7:09pm

chemistry
How would I make 500 ml's of a .35M NaCI solution. MW= 58.44 ( I know how to do the first part) How many micromoles of NaCI would be present in that solution? What would be the percentage of NaCI in that solution?
Wednesday, August 27, 2014 at 7:06pm

Chemistry
How do you cope with a fire on your labatory bench?
Wednesday, August 27, 2014 at 5:30pm

chemistry
A solution of HClO4 was standardized by dissolving 0.4125 g of primary standard grade HgO ina solution of KBR: HgO (s) + 4Br- + H2O → HgBr4 + 2OH- The liberated OH- consumed 46.51 mL of the acid. calculate the molarity of the HClO4
Wednesday, August 27, 2014 at 2:48pm

Chemistry Help!!!!!!!!!!!!!!
1)The equipment you would use for carrying out a simple distillation at reduced pressure (i.e. under vacuum) 2)What could be the advantage of carrying out a distillation under vacuum as compared to atmospheric pressure?
Wednesday, August 27, 2014 at 2:31pm

chemistry
35.6 g of Zn reacts with 87.1 g of Br to produce ZnBr2, the only product, with no reactant left over. How much ZnBr2 could be formed by reacting 156 g of Br? 1. 538 g 2. 45.4 g 3. 382 g 4. 220 g 5. 0.0156 g 6. 0.00262 g
Wednesday, August 27, 2014 at 12:41pm

Chemistry
Trans isomer is more stable than the Cis isomer.why?
Wednesday, August 27, 2014 at 11:05am

Chemistry
How to make 0.086M sodium phosphate when combined with 0.1N HCl has a pH of 6.2?
Wednesday, August 27, 2014 at 8:48am

Chemistry
How much water must be added to 963 g of solid sodium hydroxide needed in order to prepare a 1.50 M solution?
Wednesday, August 27, 2014 at 1:37am

Chemistry
a cap cork stopper from a bottle of liquid is not put down on a desk while you are pouring out some of the liquid why?
Tuesday, August 26, 2014 at 9:14pm

chemistry
glycine and lysine, have the following values of the relevant acid dissociation constants (pKa) glycine, pKa=2.35 lysine,pKa=10.79 For an aqueous solution of glycine alone, calculate the value of pH at which the ratio of the concentration of neutral glycine zwitterions to the ...
Tuesday, August 26, 2014 at 9:10pm

Chemistry
What procedures should you follow to:: 1. report spilling a chemical or breaking equipment? 2. cope with a fire on your lavatory bench? 3. dispose of cracked or broken glassware?
Tuesday, August 26, 2014 at 8:43pm

Chemistry
Why should you use only clean glassware?
Tuesday, August 26, 2014 at 8:31pm

Chemistry Help!!!!!!!!!!!!!!
for the following elements show the allocation of electrons to their orbitals on the basis of the Pauli exclusion principle and Hund's rule. a) Carbon b) Silicon Thanks!
Tuesday, August 26, 2014 at 6:31pm

chemistry
A 1.11 M solution of fluoroacetic acid, FCH2CO2H, is 5% dissociated in water. Calculate the value of the pKa of FCH2CO2H. pKa: ?? I dn't even know how to strt with this
Tuesday, August 26, 2014 at 6:25pm

chemistry
the boiling point increased by 2oC, what is the approximate molality of NaCl. K boiling point(water)= 0.512oC/m
Tuesday, August 26, 2014 at 6:12pm

chemistry
the density of alcohol is 0.79g/ml. find the mass of 15.5ml of alcohol? 15.5ml x 0.79g/ml = mass 12.245g
Tuesday, August 26, 2014 at 5:52pm

chemistry
the freezing point of benzene C6H6 is 5.5000C at 1 atmosphere. In a laboratory experiment, students synthesized a new compound and found that when 10.70 grams of the compound were dissolved in 294.0 grams of benzene, the solution began to freeze at 4.9740C. The compound was ...
Tuesday, August 26, 2014 at 5:41pm

chemistry
pepsin is an enzyme involved in the process of digestion. its molar mass is about 3.50 x 10^-4 g/mol. what is thr osmotic pressure in mm Hg at 30 degree oC of a 0.400g sample of pepsin in 55.0mL of an aqueous solution?
Tuesday, August 26, 2014 at 4:53pm

Chemistry
The relative molecular mass of a molecule of chlorine is 72. Which properties of the atoms in this molecule are the same? 1 radius 2 nucleon number 3 relative isotopic mass Answer: 1 only Can someone please explainnn! Thanks :)
Tuesday, August 26, 2014 at 10:47am

chemistry
The vapor pressure of ethanol is 54.68 mm Hg at 25oC. How many grams of chlorophyll , C55H72MgN4O5, a nonvolatile, nonelectrolyte (MW = 893.5 g/mol), must be added to 207.6 grams of ethanol to reduce the vapor pressure to 53.60 mm Hg ? ethanol = CH3CH2OH = 46.07 g/mol.
Tuesday, August 26, 2014 at 9:45am

Analytical Chemistry
A 500-mL buffer was prepared and it is 0.300 M in nitrous acid (HNO2 , Ka = 4.0 x 10-4) and 0.200 M in sodium nitrite, NaNO2. What will be the pH of this solution after adding 1.00 mL of 6.00 M HCl?
Tuesday, August 26, 2014 at 8:14am

chemistry
a solution is prepared by mixing 1.0 grams of benzen(c6h6) in 100g of water to create a solution total volume of 100ml.calculate the molarity,mass percent,mole fraction and molarity of benzene in the solution
Tuesday, August 26, 2014 at 4:11am

chemistry
At what angle (in degrees) must {111} planes of platinum (Pt) be exposed to a collimated beam of thee X-rays in order to obtain by diffraction monochromatic CrKα radiation.
Tuesday, August 26, 2014 at 2:14am

High School Chemistry
How many kilograms of salt water, (with a density of 1.20 g/cm^3) are needed to fill an aquarium that measures 125.0 ft^3? (Hint: Density can be used as a conversion factor to convert volume to mass.)(Remember to make use of significant figures.) I haven't the slightest ...
Tuesday, August 26, 2014 at 1:57am

Chemistry
Determine for solid manganese (Mn) the following: What is the atomic density (atoms/m) along the [110] direction of the Mn crystal? What are the number of nearest neighbors around an atom in the Mn crystal? Calculate the interplanar spacing (m) between {220} planes in the Mn ...
Tuesday, August 26, 2014 at 12:54am

chemistry
Gallium Arsenide ---------------- The charge carrier density of GaAs at 31o C is 2.25x106 cm-3. What is the charge carrier density (in cm-3) at 175oC? (The bandgap of GaAs is 1.42 eV. ) I am trying with arrhenius relationship but get confused over "charge carrier density&...
Monday, August 25, 2014 at 9:50pm

ap chemistry
A powder has a mass of 40.0g. When the powder is added to 30.0mL of water, the total volume is 45.0mL. What is the density of the powder
Monday, August 25, 2014 at 9:47pm

chemistry
calculate the Henry's law proportionality constant for N2? partial pressure at 1 atm=0.78 atm solubility at 1 atm= 5.3 x 10^-3 mol/L
Monday, August 25, 2014 at 8:16pm

chemistry
the vapor pressure of pure water at 60 c is 157 mmHg. what is the vapor pressure of this solution at the same temperature, in mm Hg?
Monday, August 25, 2014 at 8:05pm

chemistry
calculate the Henry's law proportionality constant for N2? partial pressure at 1 atm=0.78 atm solubility at 1 atm= 5.3 x 10^-3 mol/L
Monday, August 25, 2014 at 7:38pm

Nuhu Bamali Poly zaria Nig
Chemistry volumetric analysis. B is a solution of Na2CO3 containing 5g/dm3. A is a solution of oxalic acid of uknown concentration 25cm3 of 25.25,25.0 and 24.80 respectively (I) Calculate the average volume of acid used (II) The molar concentration of solution A (III) The ...
Monday, August 25, 2014 at 7:33pm

chemistry
Gallium Arsenide ---------------- The charge carrier density of GaAs at 31o C is 2.25x106 cm-3. What is the charge carrier density (in cm-3) at 175oC? (The bandgap of GaAs is 1.42 eV. )
Monday, August 25, 2014 at 7:32pm

chemistry
what is the solubility of N2 at a pressure of 10 atm? partial pressure at 1 atm=0.78 atm solubility at 1 atm= 5.3 x 10^-3 mol/L
Monday, August 25, 2014 at 7:26pm

chemistry help!
The Colorado River is diverted to flood fields. If the river is flowing at 17,600 ft3/s , how long will it take to flood a 5500 acre field to a depth of 2.00 meters? Note that 1 acre=43560ft2.
Monday, August 25, 2014 at 6:55pm

chemistry
The charge carrier density of GaAs at 31oC is 2.25x106 cm-3. What is the charge carrier density (in cm-3) at 175oC? The bandgap of GaAs is 1.42 eV.
Monday, August 25, 2014 at 3:17pm

Chemistry
At 1 atm, how much energy is required to heat 43.0 g of H2O(s) at –22.0 °C to H2O(g) at 169.0 °C?
Monday, August 25, 2014 at 10:37am

Chemistry
what is the symbol for gold
Monday, August 25, 2014 at 10:08am

AP Chemistry
4.50 grams of sodium phosphate is mixed with 3.75 grams of barium nitrate. How many grams of barium phosphate can be produced?
Monday, August 25, 2014 at 2:40am

chemistry
Propylene (or propene in proper IUPAC nomenclature), H2C=CH-CH3, can be reacted by addition polymerization to form polypropylene (PP). The process is initiated with the radical, I*. Choose the image above that properly indicated the location of the unpaired electron, *. What ...
Monday, August 25, 2014 at 1:36am

chemistry
Select the appropriate electron domain arrangement for ICl3 If you are using electron pairs in your structure, they can be noted with (ep). > I choose trigonal-bipyramidal What is the atomic geometry of this molecule? > I think this only wants the atoms without the lone ...
Sunday, August 24, 2014 at 10:47pm

chemistry
a)Rank the following 3 tetrachloride compounds in terms of increasing boiling point: carbon tetrachloride (CCl4), methane (CH4), dichloromethane (CH2Cl2) b) Which molecule ( KI or LiF ) has the higher boiling point? c)Select the single most important reason below to justify ...
Sunday, August 24, 2014 at 10:42pm

Chemistry
Jimmy is riding his bike at a speed of 5.5m/s. How long will it take him to go 2 miles? I tried using Dimensional Analysis, but how could you go from 5.5 miles a second to 2 miles?
Sunday, August 24, 2014 at 9:18pm

chemistry
In an effort to purify the output from a catalytic chemical reaction, C-Cl bonds are to be broken in a gaseous compound by means of LASER radiation. Determine the longest wavelength of radiation still capable of breaking the C-Cl bond. Express your answer in meters. [Given: ...
Sunday, August 24, 2014 at 8:11pm

chemistry
A 35.0g sample of ethylene glycol is dissolved in 500.0g of water. The vapor pressure of water at 32C is equal to 35.7mm Hg. What is the vapor pressure of the water-ethylene glycol solution at 32C?
Sunday, August 24, 2014 at 2:30pm

chemistry
The concentration of CO2 in an unopened soda can is 0.0506 m at 25 C. What is the partial pressure of CO2 gas in the can?
Sunday, August 24, 2014 at 2:24pm

chemistry
Determine the potential (V) by which a proton must be accelerated so as to assume a particle wavelength of 0.0293 nm. ---- This is what I did, dunno if right - wavelength in meters = 2.93*10^-11 m - used DeBroglie relation to find energy lambda = h / mv, v from kinetic energy...
Sunday, August 24, 2014 at 2:08pm

chemistry
The partial pressure of O2 in your lungs varies from 25 mm Hg to 40 mm Hg. What mass of O2 can dissolve in 1.0L OF water at 25.0oC when the O2 partial pressure is 40. mm Hg?
Sunday, August 24, 2014 at 1:59pm

chemistry
Calculate the wavelength (in m) of a photon capable of exciting an electron in Li2+ from the state n= 3 to the state n=5
Sunday, August 24, 2014 at 11:37am

chemistry
a) Calculate the number of moles of nitrogen dioxide, NO2, that could be prepared from 79.0 mol of nitrogen oxide and 82.0 mol of oxygen. 2NO(g)+O2(g)⟶ 2NO2(g) b) Identify the limiting reagent and the excess reagent in the reaction. What would happen to the potential ...
Sunday, August 24, 2014 at 10:20am

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