Wednesday
May 25, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
Consider a sample of excited atoms that lie 3.211 × 10–19 J above the ground state. Determine the emission wavelength (in nanometers) of these atoms.
Saturday, February 13, 2016 by Bibi

Chemistry
1. As the intermolecular forces between molecules increase in magnitude, do you expect each of the following to increase, decrease or remain the same? My answers: Viscosity: increase Boiling point: increase Vapor pressure: decrease Surface tension: increase Heat of ...
Saturday, February 13, 2016 by Student

science chemistry
A ground state hydrogen atom absorbs a photon of light having a wavelength of 93.03 nm. It then gives off a photon having a wavelength of 396.9 nm. What is the final state of the hydrogen atom? Values for physical constants can be found here.
Saturday, February 13, 2016 by Anisha

Chemistry
Consider a sample of excited atoms that lie 3.211 × 10–19 J above the ground state. Determine the emission wavelength (in nanometers) of these atoms.
Saturday, February 13, 2016 by Anisha

chemistry
a) The combustion of an organic compound in the presence of excess oxygen produced a gas , which makes clear lime water turbid. What element can be identified?  b) A sample of this compound is treated with hot molten sodium metal, the obtained mixture is dissolved in ...
Saturday, February 13, 2016 by angy

Chemistry-Dr.Bob
The solubility of CO2 in water at 25 degrees Celsius and P CO2= 1 atm is 0.034 mol/L. What is its water solubility under normal atmospheric conditions (in air, carbon dioxide is about 380 ppmv assuming that CO2 obeys Henry's Law?
Saturday, February 13, 2016 by Student

chemistry
a) The combustion of an organic compound in the presence of excess oxygen produced a gas , which makes clear lime water turbid. What element can be identified? b) A sample of this compound is treated with hot molten sodium metal, the obtained mixture is dissolved in water and ...
Saturday, February 13, 2016 by angy

chemistry
the reaction of methane and water is one way to prepare hydrogen for use as a fuel: methanw react with water to from carbonmonoxide and hydrogen if you begin with 995g of methane and 2510g of water, 1.which reactant is the limiting reactant? 2.what is the maximum mass of ...
Saturday, February 13, 2016 by dennis

chemistry
what mass of excess reactant remians when the reaction is completed?
Saturday, February 13, 2016 by dennis

chemistry
volume of 0.5 N sodium hydroxide required to neutralize 20 ml of 0.1 N acetic acid ?
Saturday, February 13, 2016 by gurinder

chemistry
Calculate the vapor pressure over the solution, the amount of vapor pressure is lowered at 25°c and 100°c?
Saturday, February 13, 2016 by sgal

chemistry..
(1) The same quantity of electricity is passed through 2voltameters connected in series, one copper voltmeter with copper electrode in a copper(ii) tetraoxosulphate(vi) solution. The other platinum electrode in a dilute solution of tetraoxosulphate (vi) acid. 500cm³ of ...
Saturday, February 13, 2016 by dannystein

Chemistry- Dr. Bob222
What is the final temperature and state of water when 8.50 kJ of energy is added to 10.0 g of ice at 0 degree Celsius. Helpful information: Cs (ice)= 2.1 J/g•C Heat of vaporization (water)= 40.7kJ/mol Ca (water)= 4.184 J/g•C Heat of fusion (water)= 6.02 kJ/mol Cs (...
Saturday, February 13, 2016 by Anonymous

chemistry
Calculate the number of moles of H2O2 required to produce 0.08 moles of HNO3 by the following reaction. 7 H2O2 + N2H4 2 HNO3 + 8 H2O
Friday, February 12, 2016 by levy

chemistry
(1) The same quantity of electricity is passed through 2voltameters connected in series, one copper voltmeter with copper electrode in a copper(ii) tetraoxosulphate(vi) solution. The other platinum electrode in a dilute solution of tetraoxosulphate (vi) acid. 500cm³ of ...
Friday, February 12, 2016 by dannystein

Chemistry
Consider the following reaction: Al + HBr ---> AlBr3 + H2 . When 4 moles of Al reacts with 3 moles of HBr, how many moles of H2 are formed?
Friday, February 12, 2016 by Lev

Chemistry
What is the final temperature and state of water when 8.50 kJ of energy is added to 10.0 g of ice at 0 degree Celsius. Helpful information: Cs (ice)= 2.1 J/g•C Heat of vaporization (water)= 40.7kJ/mol Ca (water)= 4.184 J/g•C Heat of fusion (water)= 6.02 kJ/mol Cs (...
Friday, February 12, 2016 by Neveah

quant chemistry
A standard solution of Mn2+ was prepared by dissolving 0.250 g of Mn in 10 mL of concentrated HNO3 (measured with a graduated cylinder). The resulting solution was quantitatively transferred to a 100 mL volumetric flask and diluted to volume with distilled water. A 10 mL ...
Friday, February 12, 2016 by John

chemistry
Limestone rock contains solid calcium carbonate that can react with acid to give products. In one experiment, 1.452 g of limestone rock is pulverised and then treated with 25.00 mL of 1.035 M HCl solution. After the reaction is completed, the resulting mixture is still acidic...
Friday, February 12, 2016 by Anonymous

Chemistry
Three isotopes of Neon occur naturally: 20Ne (mass = 19.9924 amu) 21Ne (mass = 20.9938 amu) 22Ne (mass = 21.9914 amu) If the percent abundance of 21Ne is 0.2600, what is the percent abundance of 20Ne? How do I set up for these type of problems. I tried just using two and ...
Friday, February 12, 2016 by Karen

Chemistry
How do you Find the mass (in g) of Carbon in 2.980 g Carbon dioxide? I saw the question asked before but couldn't find a solution.
Friday, February 12, 2016 by Karen

Chemistry
How much energy in kJ is needed to heat 7.0L of water from35 degrees Fahrenheit to boiling point 100 degrees Celsius. If the density of water is 1.0g/cm^3 and the heat capacity of water is Cp= 4.184J/g degrees Celsius
Friday, February 12, 2016 by Rosie

Chemistry
How many grams of ammonia NH3 are necessary to react with 1.2X10^24 molecules of oxygen?
Friday, February 12, 2016 by Hillary

chemistry
A certain gas is present in a 11.0L cylinder at 4.0 atm pressure. If the pressure I increased to 8.0 atm the volume of the gas decreased to 5.5L. Find the two constants Ki, the initial value of K, and the Kf, the final value of k, to verify whether the gas obeys boyles law.
Friday, February 12, 2016 by van

Chemistry
It is known that 1.0 L of nitrogen gas reacts with 3.0 L estequilometricamente gas ...? Edit Hydrogen to form 2.0 L of ammonia gas in the same conditions of pressure and temperature. a)What is the final volume of gas? b)5.0 L of N2 + 9.0 L H2. What final volume?
Friday, February 12, 2016 by Anonymous

chemistry
Determine how much heat (in kilojoules) is evolved or absorbed in the reaction of 1.05 g of Na with H2O: 2Na(s)+2H2O(l) →2NaOH(aq)+H2(g),ΔH∘=&#​8722;368.4 kJ
Thursday, February 11, 2016 by Jay

Chemistry
How many sig figs is 820 g of carbon (which has molar mass 12.01) supposed to have when converted to moles?
Thursday, February 11, 2016 by Anonymous

Chemistry
What is the mass of 5mole of li(li=7)
Thursday, February 11, 2016 by Usman

Chemistry
Aspirin can be prepared in the chemistry laboratory by the reaction of salicylic acid with acetic anhydride. What volume of acetic anhydride is required to produce one killogram of aspirin assuming 100%yield
Thursday, February 11, 2016 by kelvin

chemistry
Draw the structures of the three primary (1°) amines with molecular formula C5H13N that contain five carbon atoms in a continuous chain.
Thursday, February 11, 2016 by Hayley

Chemistry
Explain how the presence of several oxygen atoms in a compound containing an -OH group can make the compound acidic. I don't understand this because according to Arrhenius, bases have OH. And it doesn't apply to either Lewis's acid-base theories, or the Bronsted-...
Thursday, February 11, 2016 by Drew

Chemistry
Draw the structures of the three primary (1°) amines with molecular formula C5H13N that contain five carbon atoms in a continuous chain.
Wednesday, February 10, 2016 by Hayley

chemistry
What are the correct IUPAC names for triisopropylmethane and 2,2-dimethylcyclopentane?
Wednesday, February 10, 2016 by Hayley

Chemistry
2NO + O2 yield 2NO2 Suppose that a particular moment during the reaction nitrogen monoxide (NO) is reacting at the rate of 0.074 M/s -1. At what rate is NO2 being formed?
Wednesday, February 10, 2016 by Taylor

Chemistry 101
If a piece of granite weighing 250.0 grams is heated in boiling water to a temperature of 100 C and then placed in a calorimeter containing 400.00 grams of water, the temperature of the water increases from 20.0 C to 28.5 C. what is the specific heat of Granite?
Wednesday, February 10, 2016 by Lilly

Chemistry
List the grams of bleach solution necessary to provide 0.931g of NaClO(laundry bleach is 8.25% NaClO by weight) and the mL of bleach solution that contains the necessary amount... NaClO=74.442 g/mol. Need 0.931 grams of NaClO. Density of NaClO solution is 1.07 g/ml
Wednesday, February 10, 2016 by Niki

Chemistry
the actual yield of a reaction is 55.2g and the theoretical yield is 61.3g calculate the yield
Wednesday, February 10, 2016 by La Jon

Chemistry
The hydrogen gas is collected over water at 25.0°c. The volume of the gas is 246 ml measured at 760 mmhg. calculate the number of grams of h2 collected (vapor pressure of h2=23.76mmhg)
Wednesday, February 10, 2016 by Jocelyn

Chemistry
A gas has a volume of 500 mL at a temperature of -45.0°C. What volume will the gas occupy at 30.0°C? Show your work. What equation should I use for this one? Sorry but my allergies have me feeling drained. Where should i start on this one?
Tuesday, February 9, 2016 by bubble dragon

Chemistry
concentration of H30+ in 0.0250 moldm-3 aqueous epuation of HCL
Tuesday, February 9, 2016 by Archie

Chemistry
Two fixed charges, -4μC and -5μC, are separated by a certain distance. If the charges are separated by 20cm, what is the magnitude of the electric field halfway between the charges? My textbook says that the formula for electric field is (kq)/r^2. But Since I have ...
Tuesday, February 9, 2016 by Emma

Chemistry
If 1.6045g of anhydrous salt remains after heating 1.9045 g of CuC§¤2¡¤xH2O, determine the number of molecules of water of hydration in the original hydrate
Tuesday, February 9, 2016 by Addison

Chemistry
in a neutralization reaction, dilute tetraoxosulphate (vi) acid completely reacted with sodium hydroxide solution
Tuesday, February 9, 2016 by Archie

Chemistry
the ka value of 0.001moldm-3 solution of a weak acid is 1.6*10-6 calculate the ph and the pka
Tuesday, February 9, 2016 by Archie

chemistry
using the Kw for pure water, show that: pH = pKw - pOH
Tuesday, February 9, 2016 by william

AP CHEMISTRY
The equilibrium constant for the reaction PCl3(g) + Cl2(g) ⇀↽ PCl5(g) is 35000 at 760 ◦C. At equilibrium, the partial pressure of PCl5 was 150 bar and that of PCl3 was 8.12 bar. Calculate the equilibrium partial pressure of Cl2. Answer in units of bar. I got ...
Tuesday, February 9, 2016 by Lou

Chemistry
Calculate the mass of Na2C2O4 needed to react with 30mL of 0.050 M KMnO4. The net ionic equation is: 2MnO4- + 5C2O4-2 + 16H+ —> 2Mn+2 + 10CO2 + 8H2O I don't know where to start or how to end up with sodium oxalate. Thanks!
Tuesday, February 9, 2016 by Wayfinders

Chemistry 101
The mileage for a motorcycle with a fuel tank capacity of 22 liters is 35 miles per gallon. The density of gasoline is 0.74 g/cm^3.(dimensional analysis problem) a). How long a trip, in KM can be made on a full tank of gasoline? b). if the price of gasoline is $1.99 per gallon...
Tuesday, February 9, 2016 by Lilly

Chemistry 101
Joe Smith, the chemical engineer from Acme Chemical Company, wanted to determine the final volume in a large glass cylinder is he dropped a 12.52 pound ingot of lead whose density was 11.3 g/cm^3 into the cylinder which already contained 2500. mL of water. What is the final ...
Tuesday, February 9, 2016 by Lilly

Chemistry 101
A student using a 100mL graduated cylinder that contained 50.00mL of water. Th volume of the water increased to 57.50mL. The density of the object was 7.85 g/cm^2. How many grams did the metal object weigh?
Tuesday, February 9, 2016 by Lilly

Chemistry 101
A spherical bass has a diameter of 1.00 inch and a mass of 2.00 grams. Will the ball float or sink water? Remember that if the ball's density if greater than 1.00 g/mL the density of water, the ball will sink. Also remember to use dimensional analysis.
Tuesday, February 9, 2016 by Lilly

Chemistry
An aqueous solution of a molecular compkind freezes at -0.086 degrees Celsius. What is the molality of the solution?
Tuesday, February 9, 2016 by Dalli

chemistry
Predict how the compound Calcium Chloride would react to calcium nitrate, silver nitrate, Silver Nitrate + Ammonium Hydroxide,Silver Nitrate + Sodium Thiosulfate?
Tuesday, February 9, 2016 by jill

AP Chemistry
Determine the pH of an HF solution with a 4.70x10^-2M and 2.20x10^-2M. I tried this by looking up the Ka and putting it over molarity-ka squared. Am I doing something wrong? Can someone please show me the proper way to solve this problem?
Tuesday, February 9, 2016 by KC

Chemistry
Consider the following reaction. 2A(aq) (Two way arrows) B(aq) Kp = 5.48*10^-5 at 500K If a sample of A at 3.10atm is heated to 500K, what is the pressure of B at equilibrium? I know I need to do the ICE table, but am having trouble solving for x once I plug everything in. &...
Tuesday, February 9, 2016 by Ashtyn

Chemistry
For 2 SO2(g) + O2(g) equilibrium reaction arrow 2 SO3(g), Kp = 3.0 104 at 700 K. In a 2.00-L vessel the equilibrium mixture contains 1.21 g of SO3 and 0.183 g of O2. How many grams of SO2 are in the vessel?
Monday, February 8, 2016 by Jonathan Redd

chemistry
How many moles of chlorate ions, zinc ions, and oxygen atoms are present in 0.433 mol of zinc chlorate?
Monday, February 8, 2016 by Kaitlyn

Chemistry
How many moles of carbonate ions, aluminum ions, and oxygen atoms are present in 39.0 g aluminum carbonate?
Monday, February 8, 2016 by Kaitlyn

Chemistry
Boyle's Law says that the volume of a gas varies inversely with the pressure. When the volume of a certain gas is 2 L, the pressure is 1065 kPa (kilopascals). What is the pressure when the volume is 15 L ?
Monday, February 8, 2016 by Marie

chemistry
How the volume of the individual gas particles compared to the distance between each particle?
Monday, February 8, 2016 by Boberto

Chemistry
I have to calculate the heat capacity of a coffee cup calorimeter, but I'm not sure how. I have NaCl and NaOH, they both start at the same temperature, and I have the mass of the solutions used. I'd appreciate the help!
Monday, February 8, 2016 by Dan

chemistry
summarized the atomic structure and discovery of nucleus and protons
Monday, February 8, 2016 by lukman

Chemistry Dimensional analysis
A cyclist rides at an average speed of 18 miles per hour. if she wants to bike 212km, how long in hours must she ride? What I have so far.. 212km(10^3 miles
Sunday, February 7, 2016 by Joey

Chemistry
Calculate the mass of H2O that is produced from the combustion of 13.8 mol of C3H8n propane. C3H8 + 5O2---> 3CO2 + 4H2O known: 13.8mol C3H8 unknown: mass of H2O
Sunday, February 7, 2016 by A

Chemistry
to make a sodium chloride solution of the same molarity as household bleach (as determined in question 1) how many grams of salt would be needed for every 100 ml of solution question 1 answer: 0.871 M
Sunday, February 7, 2016 by Lola

Chemistry
Consider the thermal decomposition of potassium chlorate. 2 KClO3(s) ---> 2 KCl(s) + 3 O2(g) A mixture containing KCl and KClO3 weighing 1.80 g was heated producing 1.40 x 102 mL of O2 gas at STP. What percent of the original mixture was KClO3?
Sunday, February 7, 2016 by Ray

Chemistry
You are given a bottle of dry NaCl. Explain the procedures required to make 900mL of a 0.5M NaCl solution. The formula weight of NaCl is 58.4g/mole.
Sunday, February 7, 2016 by Ana

Chemistry
Construct a cooling curve (looks the same as a heating curve) for a substance with a molar mass of 200 that has a gas phase specific heat capacity of 2.9J/g K, a boiling point of 525 K,a liquid phase specific heat capacity of 3.24 J/g K, a freezing point of 352 K, a solid ...
Sunday, February 7, 2016 by Neveah

Chemistry
Calculate the pressure of the dry gas collected over water at 10 degree celcius and 750mmHg. Given that the vapour pressure of water at 10 degree celcius is 20mmHg
Sunday, February 7, 2016 by Dolapo

chemistry
25ml of 0.01M KIO3 solution were put to react with an excess of KI. 32.04ml of the sodium thiosulfate solution were needed to titrate the triiodide ions that were present . What is the molar concentration of thiosulfate in the solution?
Sunday, February 7, 2016 by vicky

organic chemistry
4. A 300-ml aqueous solution containing 40 g compound A is to be extracted with ether. The solubility of compound A in either at room temperature is 20 g per 100 ml and in water is 13.3 g per 100 ml. calculate the weight of the compound that would be recovered by extraction ...
Sunday, February 7, 2016 by em-em

chemistry
. In the following reaction: Fe2O3 + 3C → 2Fe + 3CO; how many grams of C are needed to react with 16.5 g Fe2O3?
Saturday, February 6, 2016 by john

chemistry
how do i decide which stationary phase to choose if solute i want to separate is relatively non-polar??
Saturday, February 6, 2016 by Anonymous

Chemistry
Equilibrium is established between Br2(l) and Br2(g) at 25.0*C. A 250.0 mL sample of the vapor weights 0.486g. What is the vapor pressure of bromine at 25.0*C, in mmHg?
Saturday, February 6, 2016 by Yvette

Chemistry
An aqueous solution is composed of 7.50 g NaCl (MM = 58.44 g/mol) diluted to 0.100 L. Calculate the osmotic pressure of the solution at 298 K a. 5.83 atm b. 9.22 atm c. 18.3 atm d. 62.8 atm
Saturday, February 6, 2016 by Kat

master chemistry
The rate constant of a chemical equation has increased from 0.100s^-1 to 2.70s^-1 upon raising the temperature from 25C to 45C. Find the activation energy. So far I done 3.30=(Ea/8.314)(-2.11x10^-4)
Saturday, February 6, 2016 by Jay

Chemistry
The vapor pressure of pure water at 10C is 9.2 torr. How many grams of MgCl2 would you need to add to 500 mL of water to drop the vapor pressure to 8.0?
Friday, February 5, 2016 by Andrew Smith

chemistry
I need help in the formula to calculate these types of problems 125ml of 0.43M of HCl + 17ml of 1.8M HCl Calculate the concentrations of solutions resulting from the mixture
Friday, February 5, 2016 by michelle

Chemistry
1,15g of a non-volatile compound is dissolved in 75,0g of benzene. The boiling point of the solution 0,125ºC has a value greater than the corresponding pure benzene. Calculate the molecular weight of the compound.
Friday, February 5, 2016 by Anonymous

Chemistry
Explain how conc. H2so4 catalysis the speed of the reaction between salicylic acid and acetic anhydride.
Friday, February 5, 2016 by Alki

Chemistry
Is the unbalanced reaction for copper + silver nitrate Cu + AgNO3 = Cu(NO3)2 + Ag or Cu + 2AgNO3 = Cu(NO3)2 + Ag?
Friday, February 5, 2016 by Anonymous

Chemistry
A Sample of M2O3 weighing 11.205g is converted to 15.380g of MCL3, where M is the unknown metal, then what is the identity of M?
Friday, February 5, 2016 by Justin

chemistry
What are the names of Calcium in its ionic form the relationship of that element, in its ionic form, with our health? I understand calcium chloride is ionic form of calcium but the others what are others that have a relationship with our health?
Friday, February 5, 2016 by Anonymous

general chemistry
mercury has density of 13.53 g/mL. what is the mass of 345mL of mercury? D=13.53g/mL Mass=345mL 13.53/345=0.039217391 i just do not think i am doing this right
Friday, February 5, 2016 by lisa

chemistry
what is the bond order of oxygen
Friday, February 5, 2016 by kidist

chemistry
what is the mass of an empty 75 mm test tube?
Friday, February 5, 2016 by anonymous

chemistry
A 7.30-L container holds a mixture of two gases at 45 °C. The partial pressures of gas A and gas B, respectively, are 0.410 atm and 0.620 atm. If 0.150 mol of a third gas is added with no change in volume or temperature, what will the total pressure become?
Thursday, February 4, 2016 by grace

Chemistry
What is the principal of seperation of metal ions in qualitative analysis?
Thursday, February 4, 2016 by Ri

Chemistry
suppose 4.52 g H2o and 20.09 g So3 are produced. How many grams of H2So4 decompose? Wouldn't the answer be 24.61?
Thursday, February 4, 2016 by Anonymous

Chemistry
1. How could a chemistry student change NaOH(s) to NaOH(aq)? s= solid aq= aqueous 2.) How could a chemistry student change NaOH(s) to NaOH(l) s= solid l= liquid
Thursday, February 4, 2016 by Anonymous

chemistry
Let I know the equation with symbol of 'iron2oxide from iron fillings'
Thursday, February 4, 2016 by chaw

Social Studies
In what way is geography an integrative science? a. Geography is an integrative science because it examines Earth in both physical and human terms.*** b. Geography is an integrative science because it borrows from physical sciences such as chemistry, biology, meterology, and ...
Thursday, February 4, 2016 by Kaai97

Chemistry- Dr. Bob222
Methanol (CH3OH) is a colorless volatile liquid, formerly known as wood alcohol. It boils at 65.0 °C and has a heat of vaporization ΔHvap = 37.4 kJ/mol. What is methanol’s vapor pressure at 22.0 °C? My answer: 109.5 torr
Thursday, February 4, 2016 by Anonymous

English academy.chemistry
Complete the following reaction 2F2(g) +2H2O(ĺ)=?
Thursday, February 4, 2016 by Anonymous

Chemistry
2F2(g)+2H2O(l)=?
Thursday, February 4, 2016 by Mainu

Chemistry
Complete the reaction- 2F2(g)+2H2O(l)=?
Thursday, February 4, 2016 by Mainu

Chemistry
What happens to the pH of an acidic solution when it is heated
Thursday, February 4, 2016 by Anonymous

Chemistry
Is optimum ph for enzyme 7-14?
Thursday, February 4, 2016 by Ri

Chemistry
How many liters of nitrogen monoxide are produced when 15.0 L of water vapor are also produced (assume STP)
Thursday, February 4, 2016 by Levie

chemistry
1. Identify the strongest intermolecular forces present in each of the following: CH3CH2CH3 C6H5NH2 HF SO2 CH3CH2OH NF3 CH3Cl
Thursday, February 4, 2016 by edwin

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Homework Help: Science