Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
What is the lewis dot structure for copper?
Thursday, February 21, 2013 at 9:10am

chemistry
why is the graph of the meliting points of hydrocarbons not consistent?
Thursday, February 21, 2013 at 8:30am

Chemistry
The molal boiling-point constant for water is 0.51 degrees C/molal. The boiling point of a 1.00 molal solution of Ca(NO3)2 should be increased by: A.) exactly 1.53 or B.) Somewhat less than 1.53 This is how I worked the problem: Ca(NO3)2 dislocates into 3 mole particles. ...
Thursday, February 21, 2013 at 5:32am

Chemistry
NH4NO3 is frequently used as a fertilizer and in explosive compounds dlta Hf values of this compound nd H20 are -365kJmol-1 and -286kJmol-1 respectively. Calculate the amount of heat released bye the dissociation of 1mol of NH4NO3 according to the following reaction 2NH4NO3--&...
Thursday, February 21, 2013 at 5:20am

Chemistry
20cm3 of 0.500moldm-3 H2SO4 was consumed to neutralize 50cm3 of 0.400moldm-3 NaOH. The temperature of the system is increased by 36 degree C. The heat capacity of the calorie meter was 39 JK-1, and the heat capacityof the solution is 4.2JK-1. Find the enthalpy of ...
Thursday, February 21, 2013 at 5:13am

Chemistry
What is the ionic equation for (NH4)2CO3=2NH3+CO2+H2O
Thursday, February 21, 2013 at 1:45am

Chemistry
20cm3 of 0.500moldm-3 H2SO4 was consumed to neutralize 50cm3 of 0.400moldm-3 NaOH. The temperature of the system is increased by 36 degree C. The heat capacity of the calorie meter was 39 JK-1, and the heat capacity of the solution is 4.2JK-1. Find the enthalpy of ...
Thursday, February 21, 2013 at 1:29am

Chemistry
How many grams of CS2(g) can be prepared by heating 12.9 moles of S2(g) with excess carbon in a 7.00 L reaction vessel held at 900 K until equilibrium is attained? Stoichiometry is 1 to 1
Thursday, February 21, 2013 at 1:07am

chemistry
the concentration of urea (MW=60.0g/mol) in a soltuion prepared by dissolving 16g of urea in 39g of H2O is ____ molal
Thursday, February 21, 2013 at 12:01am

Chemistry
250cm3 of 0.400moldm-3 NaOH and 250cm3 of 0.400moldm-3 HCl is allowed to react in a calorie meter. If the initial temperature of the system is 17.05 degree C and the final temperature is 19.55 degree C,Find the enthalpy of neutralization for the reaction. The mass of the ...
Wednesday, February 20, 2013 at 11:58pm

Chemistry
If calcium carbide has a standard enthalpy of formation of -59.8 kJ/mol and acetylene has a standard enthalpy of formation of 226.73 kJ/mol, what is the standard enthalpy change for the reaction?
Wednesday, February 20, 2013 at 11:48pm

Chemistry
Thanks Dr.Bob On the periodic table, which block has 5 orbitals? Is it s, p or f? Thanks.
Wednesday, February 20, 2013 at 11:16pm

Chemistry
Rank these to highest pH to lowest pH: NH3, KOH, Ca(OH)2, HBr, HBrO I put these in the same order for highest pH to lowest but still get it wrong.
Wednesday, February 20, 2013 at 10:52pm

Chemistry/physics
i have a density of 1.9x 10 (negative cubed)g/cm cubed.and i have a mass of 50.0 g. do i need to convert my density in order to find my volume?
Wednesday, February 20, 2013 at 9:59pm

Chemistry
How many grams of solute are present in 875 mL of 0.180 M KBr?
Wednesday, February 20, 2013 at 9:17pm

chemistry
what is the volume of a 3.00M solution made with 122g of LiF
Wednesday, February 20, 2013 at 9:08pm

Chemistry
A 100 L reaction container is charged with 0.724 mol of NOBr, which decomposes at a certain temperature** (say between 100 and 150 oC) according to the following reaction: NOBr(g) ↔ NO(g) + 0.5Br2(g) At equilibrium the bromine concentration is 1.82x10-3 M. Calculate Kc (...
Wednesday, February 20, 2013 at 8:59pm

Chemistry
You know how when you do calculations for the enhaloy change of a reaction you start sort of like this?: NH3(aq) + HCl(aq) → NH4Cl(aq) 25 mL 25 mL 1.0 mol/L 1.0 mol/L n = c x v = 1 mol/L x 0.025L = 0.025 mol How come you only need the moles of one of the reactants? I ...
Wednesday, February 20, 2013 at 7:38pm

Chemistry. Please help!
Fe3+ + I1- ¨ Fe2+ + I2 1. Balance the equation 2. Which element is being oxidized? 3. Which element is the reducing agent?
Wednesday, February 20, 2013 at 7:32pm

chemistry concentrations
You have combined the following: 7.92mL of 1.122M Fe(NO3)3(aq), 5.02mL of 1.849M NaCl(aq), and 7.09mL of water. What is the concentration of chloride ions in the resulting solution? Assume liquid volumes are additive
Wednesday, February 20, 2013 at 7:14pm

Chemistry
The dye molecule 7-aminocoumarin has an extinction coefficient of 2800M-1cm-1 at 432nm. An aqueous sample of 7-aminocoumarin is placed in a cuvette with a 1.00cm path length and the absorbance is found to be 1.75 at 432nm. What is the molarity of 7-aminocoumarin in this sample?
Wednesday, February 20, 2013 at 7:13pm

Chemistry...
The oxygen gas emitted from an aquatic plant during photosynthesis is collected over water at a temperature of 25 degrees celsius and a total pressure of 762 torr. What is the partial pressure of the oxygen gas? What formula do I need to use?
Wednesday, February 20, 2013 at 7:11pm

Chemistry
Can you check my calculations, please? It's for a lab we did in order to find the the enthalpy of formation of NH4Cl(s). My final answer was -299.4 kJ, while the theoretical, or actual, value is -314.4 kJ. It was the closest value out of everyone in the entire class. I'...
Wednesday, February 20, 2013 at 6:27pm

chemistry
What is the pressure in millimeters of mercury of 0.0115mol of helium gas with a volume of 211ml at a temperature of 25 degrees celsius? Ok so I've come up with many different answers but none are right. You convert the mL to L and the temperature to Kelvin by adding 273 ...
Wednesday, February 20, 2013 at 6:00pm

Chemistry
Question asking about how enzymes affect the rate of a reaction. Check all that apply 1. They shift the reaction equilibrium towards the products. 2. They increase the concentration of the reactants. 3. They lower the activation energy of the reaction. 4. They decrease the ...
Wednesday, February 20, 2013 at 5:26pm

chemistry
If the freezing point of the solution had been incorrectly read 0.3degrees C lower than the true freezing point, would the calculated molar mass of the solute be too high or too low? Explain.
Wednesday, February 20, 2013 at 5:14pm

gen. chemistry
an unknown solid substance weighs 121g. calculate the specific heat if 425.2 cal raise the temperature of the solid from 24.0 degrees C to 55.7 degrees C.
Wednesday, February 20, 2013 at 4:36pm

chemistry
if 5.06 g of limestone decomposes by heat to 4.25 g of calcium oxide and carbon dioxide gas,what is the mass of carbon dioxide gas produced?
Wednesday, February 20, 2013 at 4:32pm

Chemistry help
The Lab experiment we did today was to analyze an antacid tablets to determine the actual content of NaHCO3. Suppose I dropped the tablets into the beaker and some of the reaction mixture splashed out. Would my final calculated mass of sodium bicarbonate in the tablet be ...
Wednesday, February 20, 2013 at 4:15pm

chemistry
calculate the volume of Nitrogen gas to produce 5.6 dm cube of nitric oxide at STP ,N2 + O2 = 2NO
Wednesday, February 20, 2013 at 3:47pm

Chemistry
A thoroughly dried 1.281g sample of Na2SO4 is exposed to the atmosphere and found to gain 0.383g in mass. What is the percent, by mass, of Na2SO4*10 H2O in the resulting mixture of anhydrous Na2SO4 and the decahydrate
Wednesday, February 20, 2013 at 3:38pm

chemistry
Why is Fe3+ likely to precipitate in the presence of oxygen?
Wednesday, February 20, 2013 at 3:32pm

chemistry
Why is graphite more stable than diamond at 25˚C and 1 atm?
Wednesday, February 20, 2013 at 3:31pm

chemistry
What is the density of a 28.87 g irregularly shaped object if the initial volume of water was 24.7 ml and the volume rose to 64.1 ml after the object was added?
Wednesday, February 20, 2013 at 2:39pm

chemistry
What is the density of a block of unknown material with a mass of 13.26 g if the dimensions are: length = 2.2 cm height = 1.7 cm width = 4.1 cm
Wednesday, February 20, 2013 at 2:11pm

Chemistry
Iodine clock reaction If the thiosulfate ion solution was omitted what would appear in the solution? I know that once the thiosulfate ion is responsible and exhaubated the reaction rate stops and iodine is presented in the color blue. In that case, if thiosulfate ion solution ...
Wednesday, February 20, 2013 at 12:03pm

chemistry
how many grams of copper can be heated from 21.5 c to 35.4 c by the heat energy released when 245 g of aluminum cools from 80.5 c to 49.8 c
Wednesday, February 20, 2013 at 10:56am

Chemistry
How many moles of gas must be forced into a 4.8L tire to give it a gauge pressure of 30.8psi at 30 degrees celsius? The gauge pressure is relative to atmospheric pressure. Assume that atmospheric pressure is 14.5L so that the total pressure in the tire is 45.3psi. What formula...
Wednesday, February 20, 2013 at 10:49am

chemistry
hemoglobin is the protein that transports O2 through the blood from the lungs to the rest of the body. in doing so, each molecule of hemoglobin combines with four molecules of O2. if 1.00 g of hemoglobin combines with 1.53 mL of O2 at 37 C and 743 torr, what is the molar mass ...
Wednesday, February 20, 2013 at 10:47am

chemistry
Solid white P melts then vaporizes at high temperatures. Gaseous white P effuses at a rate that is 0.404 times that of neon in the same apparatus under the same conditions. How many atoms are in a molecule of gaseous white phosphorus?
Wednesday, February 20, 2013 at 10:42am

Chemistry
How many molecules of ethane (C2H6) are present in 0.249 g of C2H6? Enter answer in scientific notation.
Tuesday, February 19, 2013 at 11:15pm

Chemistry
1) Frank and Oswalt report a molar absorptivity of 4700 L mol^-1 cm^-1 for thiocyanatoiron(lll) ion. What absorbance would you expect for a soloution that it 1.0e-4 M in thiocyanatorion(lll) ion, if the path length is 1.00 cm? 2) At a given temperature, the equilibrium ...
Tuesday, February 19, 2013 at 9:16pm

Chemistry
Consider the following equilibrium: H2CO3 (aq) ↔ H2O (l) + CO2 (g) Which direction will the equilibrium shift (left or right) if we: Increase the pressure by decreasing the volume of the system: Increase the pressure by adding Argon to the system: Addition of NaOH (aq) ...
Tuesday, February 19, 2013 at 8:55pm

Chemistry
Which of the following mixtures of KCl in water is a saturated solution and which is an unsaturated solution; 1)100g of KCl in 100mL of H2O at 40°C 2)50g of KCl in 100mL of H2O at 70°C 3) 120g of KCl in 100mL of H2O at 60°C My data is: Temperature82°C 58°C ...
Tuesday, February 19, 2013 at 8:55pm

Chemistry- Naming compounds Nomenclature
i am having trouble with this compound. Molybdenum (VI) Chromate I'm have it find its formula and can't seem to get it. Thanks for the help.
Tuesday, February 19, 2013 at 8:39pm

chemistry
A system at equilibrium contains iodine at a pressure of 0.21 and iodine at a pressure of 0.23 . The system is then compressed to half its volume.Find the pressure diiodine of when the system returns to equilibrium.
Tuesday, February 19, 2013 at 8:15pm

Chemistry/geology
Why is Fe3+ likely to precipitate in the presence of oxygen?
Tuesday, February 19, 2013 at 8:03pm

Chemistry/geology
Why is graphite more stable than diamond at 25˚C and 1 atm?
Tuesday, February 19, 2013 at 8:03pm

Chemistry
Given the following functions, answer the questions: Temperature (°C) Kw 0 1.1410−15 25 1.0010−14 35 2.0910−14 40. 2.9210−14 50. 5.4710−14 Is the autoionization of water exothermic or endothermic? (b) What is the pH of pure water at 35°C...
Tuesday, February 19, 2013 at 8:01pm

Chemistry
Use the equation for the synthesis of hydrogen to answer the following. 10 points. C (s) + H2O (l) -> CO (g) + H2 (g) deltaH = + 31.3 kcal/mol carbon deltaS = +32 cal/(mol•K) Calculate the energy change (deltaH) when 5.00 g of carbon is consumed. Calculate the energy ...
Tuesday, February 19, 2013 at 7:01pm

chemistry
assume the true concentration of the acetic acid solution is .175M and calculate the percent relative error in your measurement?
Tuesday, February 19, 2013 at 6:38pm

Chemistry
The density of solid Cr is 7.15 g/cm3. How many atoms are present per cubic centimeter of Cr? As a solid, Cr adopts a body-centered cubic unit cell. How many unit cells are present per cubic centimeter of Cr?
Tuesday, February 19, 2013 at 6:06pm

meghan
Draw and name the product obtained in the following acid-base reactions: 1. 2-isopropylpentanoic acid + NaOH 2. 2-isopropylpentanoic acid + NH3
Tuesday, February 19, 2013 at 6:00pm

Chemistry
What volume in liters would contain 5.30 x 10^24 molecules of hydrogen gas at STP?
Tuesday, February 19, 2013 at 5:41pm

Chemistry (DrBob222)
Hi, here's my (almost) 2-paged lab report introduction (hopefully you remember it from yesterday). I went to class today, and actually a lot of my other classmates' introductions were over 2 pages! Now I'm feeling kind of insecure about mine, and I'm not even ...
Tuesday, February 19, 2013 at 5:39pm

Chemistry
What volume in liters would contain 5.30 x 1024 molecules of hydrogen gas at STP?
Tuesday, February 19, 2013 at 5:39pm

Chemistry
Calculate the density a gas will have at STP if its molar mass is 41.8 g/mol.
Tuesday, February 19, 2013 at 5:38pm

Chemistry
If the pH of a solution is 6, what are the hydrogen- and hydroxide-ion concentrations? The PH of a 0.1 M MCl (M+ is an unknown cation) was found to be 4.7. Write the net ionic equation for the hydrolysis of M+ and its corresponding equilibrium expression Kb. Calculate the ...
Tuesday, February 19, 2013 at 5:36pm

chemistry
Suppose of copper (II) nitrate is dissolved in of a aqueous solution of sodium chromate. Calculate the final molarity of nitrate anion in the solution. You can assume the volume of the solution doesn't change when the copper (II) nitrate is dissolved in it. Round your ...
Tuesday, February 19, 2013 at 4:56pm

Chemistry
Determine if the solubility would increase, decrease, or stay the same: 1) A saturated solution of sugar water is cooled from room temp to 0 degrees Celsius. 2) A solution of ocean water with dissolved oxygen is heated from 10 degrees Celsius to 15 degrees Celsius. 3) A ...
Tuesday, February 19, 2013 at 2:58pm

Chemistry
What is the % M/M concentration of 5.00 mL of methanol in 25 g solution of methanol in water? The density of methanol is 0.791 g/mL. The density of water is 1.000 g/mL. What is the % V/V concentration for the solution? Please show work.
Tuesday, February 19, 2013 at 2:44pm

chemistry
If 53.62 ml of an oil weighs 48.34 g, what is the specific gravity of the oil?
Tuesday, February 19, 2013 at 2:34pm

chemistry
mass of crucible- 26.4574g mass of crucible and hydrated sample- 27.7617g mass of hydrated sample 1.3043g mass of crucible and dehydrated sample- 27.5693g mass of dehydrated sample- 1.1119g mass of filter paper- 0.7089g mass of filter paper and copper- 1.1418g mass of copper...
Tuesday, February 19, 2013 at 1:42pm

Chemistry
Consider the following equilibrium at 395K: NH4HS(s)<-> NH3(g) + H2S(g) The partial pressure of each gas is 0.265 atm. Calculate Kc for the reaction.
Tuesday, February 19, 2013 at 1:34pm

chemistry
Enter the symbol for the element represented by the following electronic configuration. [Ar]4s23d6 ??? How does this work?
Tuesday, February 19, 2013 at 12:09pm

Chemistry
What is the maximum number of electrons that can occupy a subshell with l = 2 ? (Remember that l = 0 denotes an s orbital, l = 1 denotes a p orbital, l = 2 denotes a d orbital, and l = 3 denotes an f orbital.) ?????
Tuesday, February 19, 2013 at 12:03pm

Chemistry
Another proposed mechanism problem: H2O2 + I ---> H2O +IO slow H2O2 + IO ---> H2O + O2 + I fast Which of the following statements in incorrect? a.) IO is a catalyst b.) I is a catalyst c.) The net reaction is 2H2O2 ---> 2H2O + O2 I would choose B, since IO is shown as...
Tuesday, February 19, 2013 at 6:06am

Chemistry
The decomposition of ozone may occur through the two-step mechanism shown below: step 1 O3 ----> O2 + O step 2 O3 + O ---> 2O2 The oxygen atom is considered to be: a catalyst or reaction intermediate? How am I supposed to be able to tell the difference between the two? I...
Tuesday, February 19, 2013 at 5:59am

Chemistry
Which of the following solutes, dissolved in 1000g of water, would provide a solution would the lowest freezing point? .030 mol of BaCl2, CO(NH2)2, CaSO4, CH3COOH, or .030 mol of NH4NO3 Again, the steps needed to determine for the freezing point.
Tuesday, February 19, 2013 at 5:50am

Chemistry
Which of the following solutes in aqueous solution would be expected to exhibit the smallest freezing-point lowering (assuming ideal behavior? 0.1 m NaCl .2 m CH3COOH .05 m Al2(SO4)3 .1 m MgCl2 .25 m NH3 What would be the steps to picking the right option? Because just picking...
Tuesday, February 19, 2013 at 5:44am

Chemistry
Which of the following pure liquids is the best solvent for sodium fluoride? CCl4 C2C6 HCl BCl3 or PCl5 My guess would be either CCl4 or C2C6, I need to know the reasoning behind the correct answer.
Tuesday, February 19, 2013 at 5:39am

chemistry
What is the density of a 16.54 g object if the dimensions of the block are: length = 12.6 mm height = 1.91 cm width = 0.0140 m
Tuesday, February 19, 2013 at 12:32am

chemistry
What is the density of a block of unknown material with a mass of 15.86 g if the dimensions are: length = 2.2 cm height = 1.7 cm width = 4.8 cm
Tuesday, February 19, 2013 at 12:31am

chemistry lab
A volume of water delivered using a buret has a mass of 2.67 g. What was the final volume reading on the buret if the inital volume reading was 0.10 ml? [assume the density of water is 1.00g/mL]ml
Tuesday, February 19, 2013 at 12:30am

Chemistry
CH4(g) + 2O2(g) = CO2(g) + 2H20(g). What volume of O2 is required to react with 2.0 mol CH4 at 50 degrees Celsius and .500 atm?
Monday, February 18, 2013 at 11:51pm

Chemistry
I need help with this lab. Write the equation for the decomposition of the hydrate, CuSO4*XH2O. Mass of crucible and hydrate: 93.000g Mass of crucible and pure salt: 91.196g I need to calculate the following: 1. mass of water in hydrate sample(g) 2. number of moles of water in...
Monday, February 18, 2013 at 11:47pm

chemistry
A factory that specializes in the refinement of transition metals such as titanium was on fire. Provide kinetic-based arguments (concentration and temperature) explaining why water would be dangerous for the firefighters.
Monday, February 18, 2013 at 11:41pm

solid chemistry
H1P2: DECOMPOSITION OF AMMONIUM NITRATE Solid NH4NO3 (ammonium nitrate) decomposes on heating to 400°C, forming N2O gas and water vapor, H2O. (a)Write a balanced chemical equation.
Monday, February 18, 2013 at 11:24pm

Chemistry
Firstly, is this right?: Exothermic reactions have a negative enthalpy change value because the enthalpy of the reactants are greater than the enthalpy of the products *since the reactants have weaker bonds.* (especially the starred part, I'm wondering about) If so, how ...
Monday, February 18, 2013 at 11:24pm

Chemistry
two solutions are prepared using the same solute solution a: 0.27g of the solute disolves in 27.4g of t-butanol solution b: 0.23g of the solute disolves in 24.8g of cyclohexane which solution has the greatest freesing point change? show calculations and explain.
Monday, February 18, 2013 at 11:19pm

chemistry
At 25°C, Kp = 2.910−3 for the following reaction. NH4OCONH2(s) 2 NH3(g) + CO2(g) In an experiment carried out at 25°C, a certain amount of NH4OCONH2 is placed in an evacuated rigid container and allowed to come to equilibrium. Calculate the total pressure in the ...
Monday, February 18, 2013 at 11:19pm

Chemistry
I wrote an introduction for a lab report for the first time, and I was given no samples (my teacher said "feel free to ask your friends who had chemistry last semester if you can see their introductions... none of my friends took it last semester, so I have no one to ask...
Monday, February 18, 2013 at 11:17pm

chemistry
What is the maximum mass of H2O that can be produced by combining 90.8 g of each reactant
Monday, February 18, 2013 at 11:10pm

Chemistry
A sample of metallic element X, weighing 4.315g, combines with0.4810 L of Cl2 gas (at normal pressure and 20.0C) to form the metal chloride with the formula XCl. If the density of Cl2 gas under these conditions is 2.948g/L, what is the mass of chlorine? The amu of chlorine is ...
Monday, February 18, 2013 at 11:09pm

Chemistry
I need to write a balance equation of the decomposition of aluminum carbonate. I know the starting "reactant" is Al2(CO3)3 but would the "product' be 2Al + 3(CO3) ? Thanks
Monday, February 18, 2013 at 10:56pm

Organic Chemistry
I am trying to figure out if I am correct about the solubility of 9-fluorenone in NaOH and diethyl ether and the solubility of benzoic acid in NaOH and diethyl ether 9-fluorenone is soluble in diethyl ether because it can hydrogen bond with water so it is soluble in the ...
Monday, February 18, 2013 at 10:55pm

chemistry
This question id from IB exam,please help! 1)Which compound has the highest lattice enthalpy? A. CaO B. CaS C. LiF D. LiI Explain the reason ?
Monday, February 18, 2013 at 10:43pm

chemistry
1. Electronegativity differences give us a sense of a bond's polarity. Which of the following bonds would you expect to be most nonpolar: C-O, C-Si, C-B, or C-S? Answer my first anwer was C-O C-B C-S my answer C-Si can you explain a little further on what they mean by most...
Monday, February 18, 2013 at 10:29pm

chemistry
if 45 g of calcium carbide reacts with 23 g of water, how many liters of acetylene can be produced, assuming the reaction goes to completion at 60 degrees fahrenheit and 763 mmHg
Monday, February 18, 2013 at 10:06pm

Chemistry
How many grams of magnesium sulfate would you need to make 0.500 L of a 10.0% M/V solution in water? Please show work.
Monday, February 18, 2013 at 8:39pm

Chemistry
Hi! I am doing this chemistry lab of solubility curve of a solid investigation and this is for KCl. The purpose of this lab is to investigate the relationship between the solubility of potassium chloride and the temperature of its solution and to create a solubility curve for ...
Monday, February 18, 2013 at 8:37pm

chemistry
In a certain compound of copper and oxygen, a sample weighing 0.5424g contains 0.4831 g of Cu. How many moles of Cu in the sample? How many grams of Oxygen and how many moles of Oxygen are there in the sample? What is the mole ratio of Cu/O in the sample? What is the formula ...
Monday, February 18, 2013 at 8:36pm

CHEMISTRY
In a certain compound of copper and oxygen, a sample weighing 0.5424g contains 0.4831 g of Cu. How many moles of Cu in the sample? How many grams of Oxygen and how many moles of Oxygen are there in the sample? What is the mole ratio of Cu/O in the sample? What is the formula ...
Monday, February 18, 2013 at 8:35pm

Chemistry
If you want to make 75 mL of a 0.015 M solution of B(OH)3 in water, how many grams of B(OH)3 would you need?
Monday, February 18, 2013 at 7:59pm

Chemistry
Why wouldn't you do this reaction directly in a lab (and would rather use Hess' Law to determine the enthalpy of formation)?: 1/2N2(g) + 2H2(g)+ 1/2Cl2(g) -> NH4Cl(s) I don't think the reactants are that dangerous...? It's still pretty safe to do in a lab, ...
Monday, February 18, 2013 at 7:48pm

Chemistry
Help!!!!!!!!!!!! Fe + CuSO4 --> Cu + FeSO4 2.05g 7.00g 2.46g 151.8g Which reactant was limiting and how does this chemical equation support this? The numbers beneath the names are the masses in grams.
Monday, February 18, 2013 at 7:46pm

Chemistry
The vapor pressure of benzene (C6H6) at 25 degrees C is 95.1 mm Hg. What is the vapor pressure of benzene above a solution in which 5.05 g C6H5COOH (benzoic acid) is dissolved in 25 g C6H6? Answer should be 93.9 mmHg
Monday, February 18, 2013 at 7:17pm

Chemistry
How many milligrams of a mixture containing equal numbers of moles of CH and N2 at 10.0 atm total pressure will dissolve in 1.00 L of water at 20 degrees C? Answer should be 2.1 x 10^2 mg
Monday, February 18, 2013 at 7:12pm

Chemistry
At 25 degrees C and 1 atm gas pressure, the solubility of CO2(g) is 149 mg/100 g water. When air at 25 degrees C and 1 atm is in equilibrium with water, what is the concentration of dissolved CO2, in mg/100 g water? Air contains 0.037 mol % CO2(g). the answer should come out ...
Monday, February 18, 2013 at 7:09pm

Chemistry
Define a.m.u?
Monday, February 18, 2013 at 5:53pm

Chemistry
Why is the enthalpy of the reactants greater than the enthalpy of the products in an exothermic reaction? If it has something to do with the reactants having weaker bonds, why do weaker bonds have higher energy/enthalpy? It doesn't really make sense to me that weaker bonds...
Monday, February 18, 2013 at 5:47pm

chemistry
N2(g)+3H2(g)<=>2NH3(g) +▲H if uou are preparing NH3, hiw does the following increase the yield of NH3? (a) ▲[N2] ▲[H2] (b) ▲T of the chamber storing NH3 (c) ▲P of the system (d) ▲[NH3(g)] * <=> equilibrium * ▲ change
Monday, February 18, 2013 at 5:04pm

chemistry
If 22.4 dm3 of steam react with MgO, calculate the mass of the product that will form.
Monday, February 18, 2013 at 4:52pm

Chemistry
How many cubic decimeters of oxygen are needed to react with sulfur to produce 5.00 * 103 cubic decimeters of sulfur dioxide?
Monday, February 18, 2013 at 4:51pm

chemistry
Calculate the mass of sliver chloride, AgCl, and dihydrogen monosulfide, H2S, formed when 85.6g of sliver sulfide, Ag2S, reacts with excess hydrochloric acid, HcL.
Monday, February 18, 2013 at 4:10pm

chemistry
Greg reacts 5.0 moles of hydrochloric acid(HCL)with 1.5 moles of barium hydroxide(Ba(OH)2).Which reagent is the limiting reagent, and which is in excess?If the reagent runs to completion,how many moles of barium chloride(BaCl2)will be produced? CAN SOMEONE PLEASE HELP ME....
Monday, February 18, 2013 at 4:04pm

Chemistry
Carbon dioxide dissolves in water to form carbonic acid, which is primarily dissolved CO2. Dissolved CO2 satisfies the equilibrium equation: CO2 (g) <----> CO2 (aq) K=0.032 The acid dissociation constants listed in most standard reference texts for carbonic acid actually...
Monday, February 18, 2013 at 3:17pm

Chemistry
At 20.0 degrees celcius, a student collects H2 gas in a gas collecting tube. The barometric pressure is 755.2mm Hg and the water levels inside and outside the tube are exactly equal. What is the total gas pressure in the gas collecting tube?
Monday, February 18, 2013 at 3:04pm

chemistry
I. 1) Calculate the pH of the following solution: 0.1 M HF + 0.2 M NaCN Given: pKa for: HF/F- = 3.2 HCN/CN-= 9.4 2) Calculate the pH of the solution that results upon mixing 20.0 mL of 0.2000 M HCI with 25.0 mL of: a) distilled water c) 0.13 MNaOH e) 0.23 MNaOH b) 0.13 M AgN03
Monday, February 18, 2013 at 2:10pm

Math - Please Help
While rummaging in his great aunt's attic, Bernard found a small figurine that he believed to be made out of silver. To test his guess, he looked up the denisty of silver in his chemistry book and found it to be 10.5 g/cm^3. He found that the figure had a mass of 149 g. To...
Monday, February 18, 2013 at 1:16pm

Chemistry
A solution has a hydroxide-ion concentration of 7.48X10-5 M. What is it's hydronium-ion centration? I have no idea where to begin on this question...
Monday, February 18, 2013 at 1:03pm

Chemistry
How many grams of oxygen are collected in a reaction where 247 mL of oxygen gas is collected over water at a temperature of 25°C and a total pressure of 697 torr? And would i just convert 697 torr into atm and use that for pressure? And how do i find the molar mass of the ...
Monday, February 18, 2013 at 12:36pm

Chemistry
It takes 200. seconds for a sample of carbon dioxide to effuse through a porous plug and 280. seconds for the same volume of an unknown gas to effuse under the same conditions. What is the molar mass of the unknown gas? Enter your answer to 3 significant figures.
Monday, February 18, 2013 at 11:56am

Chemistry
How many grams of oxygen are collected in a reaction where 247 mL of oxygen gas is collected over water at a temperature of 25°C and a total pressure of 697 torr?
Monday, February 18, 2013 at 11:55am

Chemistry
Define a.m.u?
Monday, February 18, 2013 at 10:08am

Chemistry
What is gaseous state?
Monday, February 18, 2013 at 10:05am

Chemistry
how can you prepare 300ml of 15% h2so4 solution
Monday, February 18, 2013 at 8:31am

Chemistry
In a given 1st order reaction A ---> products, the initial concentration of A is 0.40 M. What will be the concentration of A after 15 seconds if the half-life of the reaction is 3 seconds? I found the concentration to be 1.25 x 10-2 M But then how do I find the rate ...
Monday, February 18, 2013 at 7:37am

Chemistry
I have a cyclohexane with a 3 carbon chain coming off of it. and two methyl groups on the second carbon. what is it called :/
Monday, February 18, 2013 at 3:17am

chemistry
AMU ?
Monday, February 18, 2013 at 1:01am

Chemistry
2 SO2 (g)+O2 (g)→2 SO3↑ How many grams of SO3(g) are formed if 8.45 grams of oxygen are used?
Monday, February 18, 2013 at 12:37am

chemistry
Preceed the equation of CuSO4 + Fe
Monday, February 18, 2013 at 12:03am

Chemistry
A 62g piece of ice at 0 degrees celcius is added to a sample of water at 9 degrees celcius. All of the ice melts and the temperature of the water decreases to 0 degrees celcius. How many grams of water were in the sample
Sunday, February 17, 2013 at 11:57pm

chemistry
how much pb can be isolated from 3.5kg of pbco3?
Sunday, February 17, 2013 at 10:32pm

Chemistry
Currently studying for an lab exam. Just have a few question about a typical Iodine Clock reaction lab. In an typical Iodine Clock reaction lab what would be the state of effect of an increase in the initial concentration of persulfate ion and the increase in the initial ...
Sunday, February 17, 2013 at 10:11pm

Chemistry
find the molarity of 150. g H2SO4 solute dissolved into 900. g H2O solvent
Sunday, February 17, 2013 at 9:59pm

college chemistry
Assuming that 9.0\% of the energy output of a 65W lightbulb is visible light and that the average wavelength of the light is 550 {\rm nm}, how many photons are emitted by the lightbulb each second?
Sunday, February 17, 2013 at 8:50pm

Chemistry!
The heat lost or gained by a system is related to its temperature change by a property called its heat capacity. The molar heat capacity of metals at or above room temperature equals 24.92 J K-1mol-1. The temperature of a block of copper metal (molar mass 63.55 g mol-1) fell ...
Sunday, February 17, 2013 at 8:33pm

chemistry
A helium-ﬁlled balloon contains 143 mL of gas at a pressure of 0.99 atm. What volume will the gas occupy at standard pressure?
Sunday, February 17, 2013 at 8:08pm

Chemistry
I'm trying to write a sentence like this: Exothermic reactions have a negative enthalpy change value because the enthalpy of the reactants are greater than the enthalpy of the products since the reactants have weaker bonds.... Why do weaker bonds have higher energy/...
Sunday, February 17, 2013 at 7:30pm

Chemistry
If I have 50 mL of Lead(II) Nitrate, it is possible for me to calculate how many mole is 1 mL of the substance? Thanks
Sunday, February 17, 2013 at 7:19pm

chemistry
gaseous hydrogen and fluorine combine in the reaction above to form hydrogen fluoride with an enthalpy change of -540kJ. What is the value of the heat of formation of HF(g)
Sunday, February 17, 2013 at 6:14pm

Chemistry/Physics
I'm not sure how to do this. Determine the actual ratio of 18O:16O for the following substances. a) Snow falling in Greenland at a temperature of -20 degrees C b) Water vapor in equilibrium with VSMOW c) Pore-water from sediments in the North Atlantic corresponding to the ...
Sunday, February 17, 2013 at 6:09pm

chemistry
How do I do a limiting reactant equation? The questions my teacher gave me are confusing and nothing we ever learned in class.
Sunday, February 17, 2013 at 5:50pm

Chemistry
Determine the direction of the following reaction from the relative strengths of acids and bases: H2S(aq) + C2H3O2-(aq) yields Hc2H3O2(aq) + HS-(aq) The book says this will favor the reactants. I'm confused...shouldn't this be neutral because both reactants and ...
Sunday, February 17, 2013 at 5:07pm

Chemistry
What mass of precipitate will form if 1.50 L of concentrated Pb(ClO3)2 is mixed with 0.750 L of 0.170 M NaI? Assume the reaction goes to completion.
Sunday, February 17, 2013 at 4:52pm

Chemistry
Is this right?: Energy is absorbed in order to break bonds because bond breaking requires energy. Or are these two statements completely separate?: "energy is absorbed when bonds break" and "breaking bonds require energy"
Sunday, February 17, 2013 at 4:30pm

maths
1) A chemistry teacher requires 250 milligrams of a chemical for an experiment. He has 30 grams of the chemical. How many times can he carry out the experiment? 2) A bottle contains 1.5 litres of cola. Hannah drinks 300 ml of the cola and Ben drinks 450 ml.How much of the cola...
Sunday, February 17, 2013 at 2:57pm

Chemistry
At equilibrium, the concentrations in this system were found to be [N2]=[O2]=0.100 M and [NO]=0.400 M. N2 (g) + O2 (g) --> 2NO (g) If more NO is added, bringing its concentration to 0.700 M, what will the final concentration of NO be after equilibrium is re-established?
Sunday, February 17, 2013 at 2:49pm

chemistry
25ml of a solution of na2c03 having a specific gravity of 1.25g ml required 32.9ml of a solution of hcl containing 109.5g of the acid per litre for complete neutralization. Calculate the volume of 0.84N heso4 that will be compltetly neutralized by 125g of na2c03 solution The ...
Sunday, February 17, 2013 at 12:45pm

chemistry
under what condition del(h) becomes del(u)
Sunday, February 17, 2013 at 10:20am

chemistry
what is real gas ?
Sunday, February 17, 2013 at 10:17am

chemistry
Effect of temperature on surface tension an viscosity ?
Sunday, February 17, 2013 at 10:12am

Chemistry
58% Ca3 (PO4) 2 how many phosphorus are in 10 kg bones? Ca3(po4)2+SiO2+C=CaSiO3+P4
Sunday, February 17, 2013 at 10:09am

chemistry
what is molality ?
Sunday, February 17, 2013 at 9:54am

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