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June 25, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
A solid sample is 81.0 g sodium per 1,000,000. g substance, and contains 1.92 × 10 ^21 sodium atoms, calculate the mass (g) of the sample.
Sunday, October 27, 2013 by Ale

chemistry
Based on the calculations above, which of the following equations is the one represented by this experiment? Justify your answer by comparing the moles of iron consumed and the moles of copper produced to the coefficients in the equation of your choice. (16 points) Fe + CuCl2...
Saturday, October 26, 2013 by john

Chemistry
Given the reaction 2 Na2 02 (s) + 2 H2o(i) —- 4 NaOH(s) + 02(g) triangle H= -109 KJ determine the following reactions. 16 Na2o2(s)+ 16 H2o(i)———- 32 NaOH(s) + 8 O2(g) 2 NaOH(s)—-+ 1/2 o2(g)——-Nao2(s)+ H2o(I)
Saturday, October 26, 2013 by Grace Peterson

Chemistry
What is the change in internal energy of a system that does 7.02 kj of work and absorbs 888 j of heat?
Saturday, October 26, 2013 by Grace Peterson

chemistry
An aqueous solution of copper (II) sulfate is a thermodynamic system under study. What typer of system is this if the solution is contained in a beaker on a laboratory table?
Saturday, October 26, 2013 by Grace Peterson

Chemistry
What volume of nitrogen gas can be produced from he decomposition of 37.6 L of ammonia with both gases measured at 725 degree celsius and 5.05 pressure? In the reaction in 71 what total volume of gas at 667 celsius and 11.3 atm can be produced by the decomposition at 1.19 X 10...
Saturday, October 26, 2013 by Grace Peterson

general
What are some great sites to help you with chemistry problems?
Saturday, October 26, 2013 by Grace Peterson

Chemistry
How many liters of Co2(g) can be produced in the reaction of 5.24 L and 2.65 L O2 (g) if all these gases are measure at the temperature and pressure?
Saturday, October 26, 2013 by Grace Peterson

Chemistry
How many liters of o2(g) measured at 22 degree and 763 Torr are consumed in the complete combustion of 2.55 L of dimethyl ether measured at 25 degree celsius and 748 Torr.
Saturday, October 26, 2013 by Grace Peterson

chemistry
In the formation of smog, nitrogen and oxygen gas react to form nitrogen dioxide: N2(g)+2O2(g)→2NO2(g)How many grams of NO2 will be produced when 2.1L of nitrogen at 840mmHg and 28∘C are completely reacted? I know that you use the equation n=PV/RT to get the number...
Saturday, October 26, 2013 by ellie

chemistry
A typical bathtub can hold 106 gallons of water. Calculate the mass of natural gas that would need to be burned to heat the water for a tub of this size from 56 ◦F to 87 ◦F. Assume that the natural gas is pure methane (CH4) and that the products of combustion are ...
Saturday, October 26, 2013 by maria

CHEMISTRY
Round this to three sig figs. 0.03335 Is it 0.0334? Is the rule: odd number goes up and even number stays the same? 3 is odd and is next to five...
Saturday, October 26, 2013 by Anonymous

chemistry
Why do acids and bases conduct electricity?
Saturday, October 26, 2013 by Sam

CHEMISTRY
In my lab report, I am asked to "Find the solubility of Ca(OH)2 in H2O as the temperature increases. Explain (in terms of energy) the reasons for this trend." From what I have found, Ca(OH)2's solubility goes down, but I have no idea why! It isn't a gas... it...
Saturday, October 26, 2013 by June

chemistry
4.86 mole Mg:0.112 mole O: smaller value
Saturday, October 26, 2013 by jen

Chemistry....
Wouldn't it be 3*0.234 instead of 2* 0.234? since....2Al3+ +3SO4 2- ----> Al2(SO4)3 4.) A solution is prepared by dissolving 25.0 g of aluminum sulfate in enough water to make 125.0 mL of stock solution. A 10.0 mL aliquot (portion) of this stock solution is then ...
Friday, October 25, 2013 by Anonymous

chemistry
a 100 W electric heater operates for 10 minutes to hear the gas in a cylinder. At the same time, the gas expands from 1 L to 14 L against a constant atmospheric pressure of 4.246 atm. What is the change in internal energy in Joules of the gas?
Friday, October 25, 2013 by maria

Chemistry (reposts#6)
!A 100.0 mL aliquot of 0.200 M aqueous calcium hydroxide is mixed with ! 100.0 mL of 0.200 M aqueous aluminum nitrate. a.)! Write a complete molecular equation for this reaction, including phases b.)! Write a net ionic equation for this reaction, including phases. c.) !For ...
Friday, October 25, 2013 by Anonymous

Chemistry (reposts#2)
A solution is prepared by dissolving 5.00 g of ferric chloride in enough water to make 500.0 mL of stock solution. A 50.0 mL aliquot (portion) of this stock solution is then removed and added to 75.0 mL of water. Calculate the concentrations of all ions in the final solution.
Friday, October 25, 2013 by Anonymous

Chemistry(reposts #1)
A solution is prepared by dissolving 5.00 g of stannic nitrate in enough water to make 250.0 mL of stock solution. A 15.0 mL aliquot (portion) of this stock solution is then removed and added to 75.0 mL of water. Calculate the concentrations of all ions in the final solution.
Friday, October 25, 2013 by Anonymous

Chemistry (URGENT)
Hello! Does anyone know where to find the solubility of Ca(OH)2 in water as temperature changes? I need this information to answer the discussion in a lab report.
Friday, October 25, 2013 by June

CHEMISTRY
Ion Concentrations 1.) A solution is prepared by dissolving 5.00 g of stannic nitrate in enough water to make 250.0 mL of stock solution. A 15.0 mL aliquot (portion) of this stock solution is then removed and added to 75.0 mL of water. Calculate the concentrations of all ions ...
Friday, October 25, 2013 by Anonymous

CHEMISTRY
This is regarding to the super long post. Dr.Bob, did you actually check all of my answers? Do you want me to make several small posts now? By the way I don't understand how #1 is wrong!!!!!
Friday, October 25, 2013 by Anonymous

CHEMISTRY
******* Please check. Also check sig figs. Ion Concentrations 1.) A solution is prepared by dissolving 5.00 g of stannic nitrate in enough water to make 250.0 mL of stock solution. A 15.0 mL aliquot (portion) of this stock solution is then removed and added to 75.0 mL of water...
Friday, October 25, 2013 by Anonymous

chemistry
Balance the following oxidation-reduction reactions, which occur in acidic solution, using the half-reaction method. (Use the lowest possible coefficients. (a) H2O2(l) + Pb(s) → H2O(l) + Pb2+(aq) (b) O2(g) + Mn(s) → H2O(l) + Mn2+(aq)
Friday, October 25, 2013 by Anonymous

chemistry 1
How do you write balanced equations A. Neutron emission by 88Br B. Electron absorption by 116Sb C. Positron emission by 184Hg D. Alpha emission by 229Th E. Neutron capture by 200Hg
Friday, October 25, 2013 by Alexus

chemistry
Balance these nuclear equations. Can some please help I dont understand these at all 1. 35/17 Cl + 1n -> 35/16S + _____ 2. 229/90 Th -> 4/2 He + ______ 3. 20/8 O -> 20/9F + ________ 4. 54/26Fe + 1n -> 1H + _______ 5. 104/47Ag -> 0/-1e + ______ 6. ________ + 0/-...
Friday, October 25, 2013 by jasmine

chemistry
Consider the HF solution with the concentration of 5% (w/v). Calculate its concentration in the molarity. Use four significant figures in your answer
Friday, October 25, 2013 by Anonymous

Chemistry
Okay, I have some confusion on a lab question for chemistry. The question was if you were preforming a microscale extraction of a 0.2 g of benzoic acid/fluorenone mixture (About 6 mL of dichloromethane and 2 mL of NaOH were added through out this experiment up until the final ...
Friday, October 25, 2013 by ramire2

CHEMISTRY URGENT
Does anyone have a "Chemistry in Context 6th edition" by mcgraw and hill book? I don't have one and my homework is in there. Page 30, questions 5,6 & 7. If you could, type out the questions for me that would be a HUGE help.
Friday, October 25, 2013 by michelle

Chemistry
Calculate the mass of AgCl that will dissolve in 100ml of 2 M NH3 ksp AgCl = 1.7x10^-10 and Kf of Ag(NH3)2 = 1.6x10^7
Friday, October 25, 2013 by Michelle

Chemistry
what's the density of a cube of an unknown substance if mass is 45.2g and the side of a cube is 3.2cm?
Thursday, October 24, 2013 by Nick

Chemistry
Using molar volume (STP) or the ideal gas law equation, determine the molar mass, g/mole, of each of the following:1.)11.1g of a gas that has a volume of 1.50L at STP. 2.) 0.742g of a gas that has a volume 860mL at 1.28atm and 18∘C. 3.) 2.42g of a gas that has a volume 1...
Thursday, October 24, 2013 by anonomous

chemistry
A 0.286g sample of carbon dioxide, CO2, has a volume of 585mL and a pressure of 495mmHg . What is the temperature, in kelvins and degrees Celsius, of the gas?
Thursday, October 24, 2013 by ellie

chemistry
Assign oxidation states to all atoms in compound. C2H2O4 i already know the other 2 but how do i find C C - ? H - +1 O - -2
Thursday, October 24, 2013 by Anonymous

AP Chemistry
The standard enthalpy of formation of Mn2O3 is −962.3 kJ/mol. How much heat energy is liberated when 6.5 grams of manganese are oxidized by oxygen gas to Mn2O3 at standard state conditions? Answer in units of kJ
Thursday, October 24, 2013 by Gabriella

chem
A 1L flask is filled with 1.25 g of argon at 25 degrees celcium. A sample of ethane vapor is added to the same flask until the total pressure is 1.45 atm. What is the partial pressure of argon in the flask? Chemistry - DrBob222, Tuesday, October 5, 2010 at 9:00pm mols Ar = 1....
Thursday, October 24, 2013 by kris

Chemistry
Identify the following chemical equations by type. 1. If an electric discharge produces 500 cm3 of ozone (O3), how many cm3 of oxygen (O2) are required? 3O2(g) ---> 2O3(g) 2. When 2.75 dm3 of O2 react with an excess of glucose (C6H12O2), according to the reaction below, ...
Thursday, October 24, 2013 by UnName

chemistry
Two 50mL beaker. One contains 50mL of 1.0M PbSO4 and the other contains 10mL of 0.1M Pb(NO3)2 added with 40mL of .10M KI. What is the Ksp of PbI2?
Thursday, October 24, 2013 by denny

chemistry
Two 50mL beaker. One contains 50mL of 1.0M PbSO4 and the other contains 10mL of 0.1M Pb(NO3)2 added with 40mL of .10M KI. What is the Ksp of PbI2?
Thursday, October 24, 2013 by slamj

Chemistry
A 23.16 ml volume of an H2A acid solution of unknown concentration with 2 drops of phenolphthalein required 14.24 ml of 0.135 M NaOH to reach the endpoint. What is the molar concentration of the acid solution?
Thursday, October 24, 2013 by Joy

Chemistry
Which of the following compounds is neutral in aqueous solution? A. CaCl2 B. AlCl3 C. NH4Cl D. CaO E. Na2CO3 F. CO2
Thursday, October 24, 2013 by Joy

Chemistry
What mass of Carbon dioxide is produced from the complete combustion of 4.60x10^-3g of methane?
Thursday, October 24, 2013 by Savannah

chemistry
Determination of Kf of Cu(NH3)4 (aq) with given 10mL of 6M NH3 mix with 40mL of 1M Cu. This is what I have so far: nCu= .040L x 1= .040mol nNH3= .010L x 6= .060mol Cu^2+ + 4NH3 -> Cu(NH3)4 .040 .06 0 -.040 4(-.040) +.040 0 -.1 .040 [Cu(NH3)]= .040/(.010+.040)=.80M for Kf=[...
Thursday, October 24, 2013 by slamj

Chemistry
When a pair of copper wires are connected to the (+) and (–) terminals of a 9–V battery and immersed in a solution containing I- ions, one of the wires becomes coated with I2. Besides simply wiping off the wire, how else could you remove the I2 coating?
Wednesday, October 23, 2013 by Anonymous

Chemistry
The negative terminal of a battery has an excess of electrons. If a wire connected to the negative terminal of a battery is placed in an acidic solution and bubbles were produced at the wire. Would the observed bubbles be consistent with oxidizing water to O2 or reducing H+ to...
Wednesday, October 23, 2013 by Anonymous

Chemistry
K2Cr2O7, H2O2 and KMnO4 are all oxidizing agents. Common products of their reduction are Cr3+, H2O and Mn2+. Identify the change in oxidation number for the involved elements.
Wednesday, October 23, 2013 by Anonymous

Chemistry
You have a metal tank containing 74.0 moles of nitrogen gas at a pressure of 15.0 atm. If the pressure is measured at a temperature of 25.0 °C, then the volume of the tank must be ___ liters
Wednesday, October 23, 2013 by Daud

chemistry
A 30 mL sample of .165 M propanoic acid is titrated with .300M KOH. Calculate the pH at each volume of added base: 0 mL, 5 mL, 10, equivalence point, one-half equivalence point, 20 mL, 25 mL. Use calculations to make a sketch of the titration curve.
Wednesday, October 23, 2013 by Anonymous

chemistry
A 0.286g sample of carbon dioxide, CO2, has a volume of 585mL and a pressure of 495mmHg . What is the temperature, in kelvins and degrees Celsius, of the gas?
Wednesday, October 23, 2013 by rose

Chemistry
What is the volume in liters of 3.0moles methane gas, CH4, at 12∘C and 1.48atm ?
Wednesday, October 23, 2013 by rose

Chemistry Hess's Law
(1) 2 Ni(s) + O2 (g) --> 2NiO(s) delta H= -479.4 kJ (2) Ni(s) + Cl2(g) --> NiCl2(s) delta H= -305.3 kJ Using equations 1 and 2 and Hess's Law, determine the amount of moles Nickel (ii) Chloride that was combusted given the following: volume = 15.45 L pressure = 2.29 ...
Wednesday, October 23, 2013 by Brian

chemistry
A microwave oven heats by radiating food with microwave radiation, which is absorbed by the food and converted to heat. Suppose an oven's radiation wavelength is 12.5 cm. A container with 200 mL of water was placed in the oven and heated. How many photons are required to ...
Wednesday, October 23, 2013 by Katie

Chemistry
Is a more negative corrosion potential more susceptible to corrosion or a less negative corrosion potential?
Wednesday, October 23, 2013 by John

HELP!! Chemistry
1. Calculate the density of a material that has a mass of 52.497 g and a volume of 18.5 cm3. 2. A student finds a rock on the way to school. In the laboratory he determines that the volume of the rock is 29.7 cm3, and the mass in 139.943 g. What is the density of the rock? 3. ...
Wednesday, October 23, 2013 by _Unknown

chemistry
What is the change in enthalpy for an isothermal, isentropic compression of an ideal gas from 2 atm to 12 atm?
Wednesday, October 23, 2013 by Carl

Chemistry
What would happen to the values of the pigments if we were to increase the relative concentration of acetonein the developing solvent?
Wednesday, October 23, 2013 by Kieu

chemistry
Iron reacts with chlorine to form iron(iii)chloride. A)How many chlorines react with 1.86g of iron? B)What mass of iron(iii)chloride is produced?
Wednesday, October 23, 2013 by Ava

Chemistry
List a series of test that would determine the order of activity (least active to most active) for the following metals: Zn, Mn, and Ag.
Tuesday, October 22, 2013 by Sam

Chemistry
Solutions of potassium carbonate, copper(II) chloride, and lead(II) nitrate are each added to a beaker. Will any compound(s) precipitate from solution? Write a balanced net ionic equation for any precipitation reaction that occurs. I have gotten this so far: K2CO3(aq) + CuCl2(...
Tuesday, October 22, 2013 by Ali

Chemistry
How many atoms of nitrogen are in the same amount of ammonia? Use molar mass.
Tuesday, October 22, 2013 by anonymous

chemistry
What mass of magnesium chloride is formed in the reaction between 7 g of Mg and 7.9 g of Cl2
Tuesday, October 22, 2013 by anonymous

chemistry
if 5.2 grams of bismuth react under certain conditions with 10.0 g of oxygen what is the empirical formula of the bismuth formed
Tuesday, October 22, 2013 by Katie

CHEMISTRY
What volume of 0.400 M Hg(NO3)2 is needed to precipitate all the I- ions from 250.0 mL of 0.300 M FeI3 There will be a follow-up questions so pay attention to my post!
Tuesday, October 22, 2013 by Anonymous

Chemistry- DrBob222
I completed this question like you told me to. Are the answers correct? Is my method for finding the molecular formula correct? 2.4g of a compound of carbon, hydrogen and oxygen gave on combustion, 3.52g of CO2 and 1.44g of H2O. The relative molecular mass of the compound was ...
Tuesday, October 22, 2013 by Ava

ap chemistry
Suppose that coal of density 1.5 g/cm3 is pure carbon. (It is, in fact, much more complicated, but this is a reasonable first approximation.) The combustion of carbon is described by the equation C(s) + O2(g) −! CO2(g) H◦ = −394 kJ What is the value of q...
Tuesday, October 22, 2013 by gabriella

ap chemistry
How much heat is required to heat 19 g of solid silver from 100 ◦C to liquid silver at 961◦C? The specific heat of solid silver is 0.235 J/g ·◦ C, and the heat of fusion of silver at its melting point of 961◦C is 11.3 kJ/g. Answer in units of kJ
Tuesday, October 22, 2013 by gabriella

ap chemistry
Consider the specific heats CH2O(s) = 2.09 J/g ¡¤◦ C. CH2O(§¤) =4.18 J/g ¡¤◦ C. CH2O(g) = 2.03 J/g ¡¤◦ C. The heat of fusion for water is 334 J/g and the heat of vaporization for water is 2260 J/g. Calculate ...
Tuesday, October 22, 2013 by gabriella

ap chemistry
Consider the specific heats H2O(s) =2.09 J/g ¡¤◦C,H2O (§¤) = 4.18 J/g ¡¤◦C, and H2O(g) = 2.03 J/g ¡¤◦C. The heat of fusion for water is 334 J/g and its heat of vaporization is 2260 J/g. Calculate the amount ...
Tuesday, October 22, 2013 by gabriella

ap chemistry
When 0.515 g of compound X is burned completely in a bomb calorimeter containing 3000 g of water, a temperature rise of 0.243◦C is observed. What is Urxn for the combustion of compound X? The hardware component of the calorimeter has a heat capacity of 3.12kJ/◦...
Tuesday, October 22, 2013 by gabriella

ap chemistry
A sample of 1.67 grams of Z is dissolved into 500 grams of water which is in a Styrofoam coffee cup. The temperature is monitored and is found to rise from 25.594◦C to 26.041◦C. What is Hsolution for substance Z? Assume no heat is lost/gained by the cup itself...
Tuesday, October 22, 2013 by gabriella

Chemistry
An 80.0 g sample of a gas was heated from 25 degree C to 225 degree C. During this process, 346 J of work was done by the system and its internal energy increased by 7495 J. What is the specific heat of the gas? J/(g∗C)
Tuesday, October 22, 2013 by Nate

ap chemistry
Calculate the energy required to heat 827 g of mercury from 37 ◦C to 42 ◦C. The specific heat capacity of Hg(§¤) is 0.138 J/g ¡¤◦ C. Answer in units of calories
Tuesday, October 22, 2013 by gabriella

Chemistry
In a constant-pressure calorimeter, 65.0 mL of 0.330 M Ba(OH)2 was added to 65.0 mL of 0.660 M HCl. The reaction caused the temperature of the solution to rise from 23.85 °C to 28.35 °C. If the solution has the same density and specific heat as water, what is ΔH ...
Tuesday, October 22, 2013 by Nate

Chemistry
If you have iron(II) oxide(s) + oxygen(g) ---> Iron(III) oxide(s), Would the answer be FeO3 + O2 ---> FeO3 for a skeleton equation?
Tuesday, October 22, 2013 by Daisha

Chemistry
Make sure the water’s Mass is still set to 1.0 kg and its Temp is 25 °C. Set the cylinder’s Height to 500 m. How does doubling the mass affect the temperature change of the water?
Tuesday, October 22, 2013 by Kaylee

Chemistry
A calorimeter contains 50.0 mL of water; both are at 21.2 degrees C. Then the 50.0 mL of water at 57.6 degrees C is added to the calorimeter. At equilibrium, the final temperature of the water and the calorimeter is 33.3 degrees C. Calculate the heat capacity, C, of the ...
Tuesday, October 22, 2013 by Jay

Chemistry
The protective action of ozone in the atmosphere comes through ozone's absorption of UV radiation in the 230 to 290 nm wavelength range. What is the energy, in kilojoules per mole, associated with radiation in the wavelength range?
Tuesday, October 22, 2013 by Bobby

college chemistry
exactly 11.2 ml of water at 23°c are added to a hot iron skillet. all of the water is converted into steam at 100°c. the mass of the pan is 1.5 kg and the molar heat capacity of iron is 25.19 j/(m·°c). what is the temperature change of the skillet
Tuesday, October 22, 2013 by eboni

Chemistry
Help! If I have 0.0031 absorbance/sec, how would I convert this to absorbance/minute? Thanks
Tuesday, October 22, 2013 by Anon

Chemistry
What does a change in the color of precipitate over time when a mixture of two solutions is combined with a reagent indicate?
Tuesday, October 22, 2013 by Cecilia

Chemistry
what is the resultig pH if 0.005 mol of NaOH is added to 100.0mL of buffer containing 0.010 mol acetic acid (CH3COOH,pKa = 4.74)and 0.010 mol sodium acetate (NaCH3COO)? (Assume the final volume is 100 mL) So i worked it out, i just need to double check the pH. Let me know what...
Tuesday, October 22, 2013 by Kyle

Chemistry...
What volume of 0.400 M Hg(NO3)2 is needed to precipitate all the I- ions from 250.0 mL of 0.300 M FeI3? Is the answer 93.8mL??
Tuesday, October 22, 2013 by Anonymous

chemistry
A tuning fork produces a sound of musical note middle C. It moves back and forth 256 time each second. what is the frequency of the tuning fork?
Monday, October 21, 2013 by Anonymous

chemistry
a tuning fork produces a sound of musical note middle C. It moves back and forth 256 time each second. What is the frequency of the tuning fork?
Monday, October 21, 2013 by Grace

chemistry
balance the following ionic equation: Sn(2+)(aq)+ Mn(2+)(aq)----- Mn(5+)(aq)+ Sn (s)
Monday, October 21, 2013 by joanne

Chemistry
The energy (in joules) of an electron energy level in the Bohr atom is given by the expression: En = -2.179E-18/n2 J where n is the quantum number that specifies the energy level. What is the frequency in Hz of the radiation emitted when an electron falls from level n = 3 to ...
Monday, October 21, 2013 by Steve

Chemistry
What kind of reaction is this (redox, precipitation, acid-base, or complex ion formation reaction)? 1. 3 Ca(s) + 2 Al^3+(aq) -> 3 Ca^2+(aq) + 2 Al(s) 2. LiHCO3(s) + heat -> Li2CO3(s) + CO2(g) + H2O(g) Complete the reaction: Ni(s) + 2 Na^+(aq) -> ?
Monday, October 21, 2013 by Fred

Chemistry
The energy (in joules) of an electron energy level in the Bohr atom is given by the expression: En = -2.179 x 10-18/n2 J where n is the principal quantum number for the energy level. What is the frequency in Hz of the electromagnetic radiation absorbed when an electron is ...
Monday, October 21, 2013 by Andy

chemistry
When a photon of light hits the surface of a metal, a photoelectron may be emitted. Some of the photon's energy is required to free the electron from the surface. The remaining energy becomes the kinetic energy of the photoelectron. The minimum energy for the emission of ...
Monday, October 21, 2013 by Kristen

Chemistry
When 1.00 kg lead (specific heat = 0.13 J g -1 C -) at 100.0 C is added to a quantity of water at 28.5C, the final temperature of the lead-water mixture is 35.2 C. What is the mass of water present?
Monday, October 21, 2013 by Bob

CHEMISTRY
The concentration of Pb2+ in a sample of wastewater is to be determined by using gravimetric analysis. To a 100.0-mL sample of the wastewater is added an excess of sodium carbonate, forming the insoluble lead (II) carbonate (267.2092 g/mol) according to the balanced equation ...
Monday, October 21, 2013 by Anonymous

CHEMISTRY
The concentration of Pb2+ in a sample of wastewater is to be determined by using gravimetric analysis. To a 100.0-mL sample of the wastewater is added an excess of sodium carbonate, forming the insoluble lead (II) carbonate (267.2092 g/mol) according to the balanced equation ...
Monday, October 21, 2013 by Anonymous

CHEMISTRY
The concentration of Pb2+ in a sample of wastewater is to be determined by using gravimetric analysis. To a 100.0-mL sample of the wastewater is added an excess of sodium carbonate, forming the insoluble lead (II) carbonate (267.2092 g/mol) according to the balanced equation ...
Monday, October 21, 2013 by Anonymous

Chemistry
How much heat, in kilojoules (kJ), is required to raise the temperature of 2.50kg Hg(l) from -20.0 to -6.0C? Assume a density of 13.6g/ml and a molar heat capacity of 28.0 J mol -1 C -1 for Hg(l). Please helpppppp .... thanks in advance
Monday, October 21, 2013 by Bob

chemistry
Al(NO3)3+ NaCl
Monday, October 21, 2013 by Anonymous

Science, Chemistry
A cylinder containing 11.0L of helium gas at a pressure of 165atm is to be used to fill birthday balloons to a volume of 2.50L per balloon and at a pressure of 1.10atm. What is the maximum number of balloons that can be inflated at a constant temperature? (remember that 11.0L ...
Monday, October 21, 2013 by Theresa

chemistry
oxidation of 1,methyl-propanone with the presence of KMnO4 & conc H2SO4 under heat.
Monday, October 21, 2013 by sree

chemistry
n an experiment, Ann mixes concentrated sulfuric acid with water in a reaction test tube. The walls of the test tube turn hot. What type of reaction has occurred?
Monday, October 21, 2013 by brittany

chemistry
If 2.0 Grams of anhydrous sodium sulfate are mixed with 2.0 grams of calcium chloride dihydrate and 2.0 grams of calcium sulfate dihydrate are collected, what is the percent yield? DO NOT ROUND A NUMBER IF USED IN A SUBSEQUENT CALCULATION
Monday, October 21, 2013 by Anonymous

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