Saturday
February 25, 2017

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Define electronegativity and then describe the trends in electronegativity within groups and across periods in the periodic table. Provide examples of the elements with the highest electronegativity value within a group and an example of an element with the highest energy ...
Thursday, October 27, 2016 by PLEASE HELP

Chemistry
A fictitious element X is composed of 78.0% of the isotope X-50, 15.0% of the isotope X-51 , and 7.0% of the isotope X-52. Estimate the atomic mass of element X. Show your work.
Thursday, October 27, 2016 by Gxlden

Chemistry
why are most elements on the periodic table found as compound in nature?
Thursday, October 27, 2016 by Briana

CHEMISTRY
WRITE A BALANCE EQUATION BETWEEN PHOSPHORIC ACID AND SODIUM HYDROXIDE USING METHYL ORANGE
Thursday, October 27, 2016 by QUEEN

Chemistry
How to find mmol? this is for dilantin by multistep synthesis lab. using 350 mg of benzoin = mmol? using 160 mg NH4NO3 = mmol?
Wednesday, October 26, 2016 by Denaiel

Chemistry
The solubility of KI in ethyl alcohol is 2.00 grams of KI in 100.0 grams of this alcohol. From this information, calculate the molarity of this solution.
Wednesday, October 26, 2016 by Anonymous

AP Chemistry
A typical bathtub can hold 94 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 59 ◦F to 101 ◦F. Assume that the natural gas is pure methane (CH4) and that the products of combustion are ...
Wednesday, October 26, 2016 by David

Chemistry
A gallon of isopropanol (IPA) weighs 6,55 lbs. Since 1 lb=453.6 grams, calculate how many moles of ethanol (MM=60.1 grams per mole) are in a gallon of this substance.
Wednesday, October 26, 2016 by Anonymous

Chemistry
What is the standard concentration of FeSCN^2+ if 18mL of 0.200M Fe(NO3)3 were combined with 2mL of 0.0020M KSCN?
Wednesday, October 26, 2016 by Victoria

Chemistry
20cm3 of 0.1m sulphuric acid was required to react with 50.0cm3 of a solution of sodium hydroxide
Wednesday, October 26, 2016 by Aliyah

Chemistry
Standardization of iodine solution was prepared using 10.0 mL of a standard, 1.00 mg/mL, ascorbic acid solution. Titration with the iodine solution required 35.80 mL to reach the end point. What is the molarity of the iodine solution?
Wednesday, October 26, 2016 by Rachael

Chemistry
Homework question? Colmanite [Ca2B6O11 * 5 H20] is a salt whose boron content gives glass high clarity. You are a buyer for an optical fiber manufacturer and want pure material. You have just received a Certificate of Analysis for a lot that is 12.8 +- 1.2% (i.e;11.6 to 14.0...
Wednesday, October 26, 2016 by Timmy

Chemistry
Note- I do not want the answers. I just need to know how to set up each.. The combustion of isopropyl alcohol (Molar Mass=60.1 g/mole) is described by the following balanced equation: 1 C2H8O + 9 O2 (g) -> 6 CO2 (g) 8H2O (l) + 4012 kJ of heat energy a) How much heat energy ...
Wednesday, October 26, 2016 by Hanna

Chemistry
What is the mass of water produced when 5 moles of hydrogen burn in the presence of excess oxygen?
Wednesday, October 26, 2016 by Flaka

Chemistry
Some pieces of jewelry react with compounds in sweat. The reaction can leave stains on your skin. Not all jewelry has this effect. Use the activity series of metals to explain this observation. please help
Tuesday, October 25, 2016 by HolfBrincl

Chemistry
A certain mixture of helium, He, and krypton, Kr, has a mass of 10.0 g and occupies a volume of 20.0 L at 25.0EC and 1.20 atm. What is the mass of He in the mixture?
Tuesday, October 25, 2016 by john

Chemistry
describe the preparation of 12 mL of a 0.050 M solution of each of the halogens, using the reactions in the preceding question. Available to you are solid Ca(OCl)2; 0.20 M solutions of NaCl, NaBr, NaBrO3, and CuSO4; a 0.40 M solution of NaI; a 0.50 M solution of H2SO4; ...
Tuesday, October 25, 2016 by Jana

Chemistry
In a three reactions system the first two reactions are endothermic with DeltaH values of 138kj and 241kj. if the final reaction is exothermic what is the minimum value of DeltaH3 that would make the overall reaction exothermic? explain your reasoning. i beleive the minimum ...
Tuesday, October 25, 2016 by Anonymous

Chemistry
Silicon carbide (SiC) is made by reacting sand (Silicon dioxide, SiO2) with powdered carbon at high temperature. Carbon monoxide is also formed. What is the percent yield if 51.4kg of SiC is recovered from processing 100.0kg of sand? What mass (in kg) of carbon would be needed...
Tuesday, October 25, 2016 by Ray

chemistry
Calculate the molarity of 12.5g of sucrose (C12H22O11) in 80mL of solution. 12.01 x 12 = 144.12 1.01 x 22 = 22.22 16.00 x 11 = 176.00 ------------------- 342.34 12.5g ----- / 342.34 = 0.003/80 = 4.56 80mL
Tuesday, October 25, 2016 by kiki

chemistry
For each pair of compounds, predict which species will have the higher molar entropy at 298 K and 1 bar. Be sure to state your reasons for your choice. 1. N2(g) vs. F2(g) 2. ICl (g) vs. BrF(g) 3. 6Li(s) vs. 7Li(s
Tuesday, October 25, 2016 by Dylan

Chemistry
How to prepare 250ml of 2.5m solution of HCL
Tuesday, October 25, 2016 by Zoe

Chemistry
What is the solvent in70% of alchol solution?
Tuesday, October 25, 2016 by Ridwan darebo

chemistry
Calculate the mass of oxalic acid needed to prepare 150 ml of 0.442 M C2H2O4.
Tuesday, October 25, 2016 by Anonymous

Sciene ( Chemistry )
The heat of neutralisation of LiOH and HCL at 25 degree celsius is 34.868 kJ/mol.The heat of ionisation of LiOH will be ?
Tuesday, October 25, 2016 by Diksha

Chemistry
What is NaOH?
Tuesday, October 25, 2016 by Grace

chemistry
What is the wavelength of radiation whose frequency is 5.93 x 10^14 s-1
Tuesday, October 25, 2016 by E

Chemistry
A 250 g mass of material has a temperature of –45˚C. Its specific heat is 0.36 J/gˑ˚C. How much heat energy is required to raise its temperature to 10˚C? (its melting point is 23 ˚C)
Monday, October 24, 2016 by Leandra

Chemistry
Calculate the mass of water produced when 9.53 g of butane reacts with excess oxygen
Monday, October 24, 2016 by Anonymous

Ap chemistry
Calculate the concentrations of all ions present in the following solutions of strong electrolytes : 2.0 times 10-3 M AL2(SO4)3
Monday, October 24, 2016 by Tiffany

Chemistry pH, acids, and bases
Trichloroacetic acid (CCl3CO2H) is a corrosive acid that is used to precipitate proteins. The pH of a 0.050 M solution of trichloroacetic acid is the same as the pH of a 0.040 M HClO4 solution. Calculate Ka for trichloroacetic acid. I just don't know where to start. How can ...
Monday, October 24, 2016 by Ryan

Chemistry - acids & bases
4. Calculate the pH of each of the solutions and the change in pH to 0.01 pH units caused by adding 10.0 mL of 2.37-M HCl to 320. mL of each of the following solutions. Change is defined as final minus initial, so if the pH drops upon mixing the change is negative. c) 0.115 M ...
Monday, October 24, 2016 by Ellen

Chemistry
What is the pH of distilled water supersaturated with CO2 at 100psi?
Monday, October 24, 2016 by Kato

Science (Chemistry) (Yield)
Using your mass of Mg (0.101g), and assuming all of the Mg burns in oxygen and forms the theoretical predicted product, calculate the theoretical yield of magnesium oxide. I wrote out the equation and it turned out to be: 2Mg+O2->2MgO I have my mass of Mg but how do I get ...
Monday, October 24, 2016 by Ray

Chemistry
SO CONFUSED PLEASE HELP!!! A certain radio wave has a wavelength of 7 inches. a. convert the wavelength of this radio wave into meters. (1 meter = 39.37) b. find the frequency of this radio wave.
Monday, October 24, 2016 by Clarissa

Chemistry
Illustrate how to prepare a 1:3 solution of 0.5M hydrochloric acid
Monday, October 24, 2016 by Adoma

Chemistry
calculate the volumes of acetone and ethanol that was used to mix together in order to produce 1 litre (1000ml) of equimolar mixture. helpful notes are, ethanol Mr=46 and a density (20 degrees C)=0.789g/ml, acetone Mr=58 and density (20 degrees C)=0.793g/ml
Monday, October 24, 2016 by Mara

Chemistry
In a three reactions system the first two reactions are endothermic with DeltaH values of 138kj and 241kj. if the final reaction is exothermic what is the minimum value of DeltaH3 that would make the overall reaction exothermic? explain your reasoning. i beleive the minimum ...
Monday, October 24, 2016 by Anonymous

chemistry
How much heat (in kilocalories) is evolved or absorbed in the reaction of 1.60 g of Na with H2O? 2Na(s)+2H2O(l)→2NaOH(aq)+H2(g), ΔH = -88.0 kcal (-368 kJ)
Monday, October 24, 2016 by Anonymous

chemistry
For each pair of compounds, predict which species will have the higher molar entropy at 298 K and 1 bar. Be sure to state your reasons for your choice. 1. N2(g) vs. F2(g) 2. ICl (g) vs. BrF(g) 3. 6Li(s) vs. 7Li(s)
Monday, October 24, 2016 by Joseph

Chemistry
0.4 moles ofpcl3 and 0.3 moles of pcl3 added to access ofC2H5OH then maximum no of moles obtained
Monday, October 24, 2016 by Abdul

Chemistry
0.4 moles of pcl3 and 0.3 moles of pcl3 added to access ofC2H5OH then maximum no of moles obtained
Monday, October 24, 2016 by Abdul

Chemistry
Na2CO3(aq)+ 2HNO3(aq)--> 2NaNO3+H2O(l)+CO2(g) how do I get net ionic?
Monday, October 24, 2016 by Anonymous

Chemistry
Zn(s)+HCl(aq)--> ZnCl2(aq)+H2(g) net ionic??
Monday, October 24, 2016 by Megan

Chemistry
How many moles of nitric oxide are formed from 0.60 mole of nitrogen dioxide
Monday, October 24, 2016 by Sienna

Chemistry
HCl(aq) + LiOH(aq)--> H2O(l) + LiCl(aq) Did I do this right? I need help on finding the net ionic equation
Monday, October 24, 2016 by Rachael

Chemistry
You have 2m^3 of a mineral ore sample. It has a mass of 1x10^4 kg. Calculate the density of the ore sample and express your results in g/cm^3 with appropriate scientific notation.
Monday, October 24, 2016 by Please Help

chemistry
Why do some reactions go to completion while others reach a state of equilibrium?
Monday, October 24, 2016 by lauren

Chemistry
How many grams of ethanol must be added to 500.0 g of water to make a solution that freezes at 0.00 degrees fahrenheit? The molal freezing point depression constant for water is 1.86 degree celsius over moles.
Monday, October 24, 2016 by Lucy

Chemistry
5.58g of Fe reacted with 3.0g of oxygen. How many moles of Fe were used?
Sunday, October 23, 2016 by Alyssa

Chemistry
In a three reactions system the first two reactions are endothermic with DeltaH values of 138kj and 241kj. if the final reaction is exothermic what is the minimum value of DeltaH3 that would make the overall reaction exothermic? explain your reasoning. i beleive the minimum ...
Sunday, October 23, 2016 by Anonymous

Chemistry
Balance the following redox reaction in basic solution. H2(g)+Fe3+(aq) ---> H2O(l)+Fe2+(aq)
Sunday, October 23, 2016 by Anonymous

Chemistry need asap
Situation: The Production of Nitric Acid can be achieved by the following process: Nitrogen monoxide gas(NO) + diatomic oxygen gas+ water (liquid) ===> Nitric Acid (aq) a. Show complete balanced reaction for process What I have: 4NO+ 3O2+ 2H2O > 4HNO3 b. The lab ...
Sunday, October 23, 2016 by John

Chemistry
When 26.16 g of iron is heated in the presence of excess chlorine gas, they will react to form 76.08 g of a compound called ntaining these 2 elements. If the molar mass of this compound is 644 g/mil find the molecular formula.
Sunday, October 23, 2016 by Josh

chemistry
proof that the energy of the first spectra line in Lyman series E =3/4Eo Eo=2.18×10-18
Sunday, October 23, 2016 by mesfin Gebre

Chemistry (atoms)
How many atoms of oxygen, O, are in 0.0595 moles of water?
Sunday, October 23, 2016 by Ray

Chemistry
0.3975 g of an oxide of divalent metal on reduction with hydrogen gives 0.090 g of water. The atomic weight of metal is: a) 63.5 b) 24 c) 55.5 d) 40
Saturday, October 22, 2016 by Avy

Chemistry, que 10
How many atoms are present in one formula unit of calcium hydrogen carbonate Ca(HCO3)2? Could someone explain to me why the answer is 11? Thank you.
Saturday, October 22, 2016 by Cheezel

Chemistry
The principal quantum number (n): 1) specifies the subshell of the orbital. 2) specifies the principal shell of the orbital. 3) specifies the 3-D shape of the orbital. 4) specifies the maximum number of electrons. 5) none of the above
Saturday, October 22, 2016 by Beth

Chemistry
According to the quantum-mechanical model for the hydrogen atom, which of the following transitions would produce light with longer wavelength: 3p to 2s or 4p to 2s? A) The 3p to 2s transition would produce light with longer wavelength. B) The 4p to 2s transition would ...
Saturday, October 22, 2016 by Sue

Chemistry
What happens to an atom when it absorbs energy? 1) The atom stores the energy for later use. 2) The atom re-emits the energy as electromagnetic radiation. 3) The extra energy increases the speed of the electrons in their orbitals. 4) The extra energy increases the oscillation ...
Saturday, October 22, 2016 by Beth

Chemistry
Calculate the wavelength, in nanometers, of the spectral line produced when an electron in a hydrogen atom undergoes the transition from the energy level n = 2 to the level n = 1.
Saturday, October 22, 2016 by Joseoh

Chemistry
Find the frequency if given energy 6.3x10^-19 Do I use the formula E=hf? 6.3x10^-19=6.626x10^-34(f) Then do I divide E and H?
Saturday, October 22, 2016 by Anonymous

Chemistry
calculate the mass ratio of 25% cacl2 solution and water to prepare 500 g of a 5% salt solution
Saturday, October 22, 2016 by Regan

Chemistry
What pressur would the propane gas sample have at 75Ml
Saturday, October 22, 2016 by Teela Lange

Chemistry
A chemist reacted 0.05 mol of sodium with water to form 50cm3 of sodium hydroxide what was the mass of sodium reacted Na+h2p-Noah+h2
Saturday, October 22, 2016 by Maria

Chemistry
A Solution Has A PH Of 3.4.What Is Its Hydrogen Ion Concentration?
Saturday, October 22, 2016 by Ola

Chemistry
The heat of combustion of C2H4 at 27 C at constant prssure is -333.3 Kcal. What will be the heat of combustion at constant volume considering the water to be in liquid state? (R=1.987 cal)
Saturday, October 22, 2016 by Sidharth

Chemistry
In a reversible reaction PCl5 ↔ PCl3 + Cl2, the value of K is 2.5. What will the partial pressure of Cl2 be?
Saturday, October 22, 2016 by Sidharth

chemistry
A Li2+ ion had its electron in an excited state. When the electron relaxed to the ground state (n = 1) a photon of light was emitted with an energy of 1.884×10−17 J. What energy level was the electron in before it transitioned to the ground state?
Friday, October 21, 2016 by malina

Chemistry
The principal quantum number (n): A) specifies the subshell of the orbital. B) specifies the principal shell of the orbital. C) specifies the 3-D shape of the orbital. D) specifies the maximum number of electrons. E) none of the above
Friday, October 21, 2016 by Katelyn

Chemistry 2
The mechanism for the reaction of nitrogen dioxide with carbon monoxide to form nitric oxide and carbon dioxide is thought to be the following. NO2 + NO2 NO3 + NO Slow NO3 + CO NO2 + CO2 Fast What would be the overall balanced equation to this reaction?
Friday, October 21, 2016 by Alanna

Chemistry
The specific heat of a metal was found to be 0.38 J/g*°C. When 0.5007 g of this metal was heated in a stream of chlorine gas, it produced 1.0586 g of a metal chloride, MClx. a. Determine the formula of the metal chloride and the accurate atomic weight of the metal. b. What is...
Friday, October 21, 2016 by Anonymous

Chemistry
The compound copper(II) nitrate is a strong electrolyte. Write the reaction when solid copper(II) nitrate is put into water:
Friday, October 21, 2016 by Liz

chemistry
A 45-kg person drinks 390. g of milk, which has a "caloric" value of approximately 3.0 kJ/g. If only 17% of the energy in milk is converted to mechanical work, how high (in meters) can the person climb based on this energy intake? [Hint: The work done in ascending is given by ...
Friday, October 21, 2016 by Dani

chemistry
A 77.40 kg piece of copper metal is heated from 19.6°C to 337.3°C. Calculate the heat absorbed (in kJ) by the metal.
Friday, October 21, 2016 by Dani

chemistry
A sheet of gold weighing 11.4 g and at a temperature of 15.6°C is placed flat on a sheet of iron weighing 24.2 g and at a temperature of 54.9°C. What is the final temperature of the combined metals? Assume that no heat is lost to the surroundings. - (11.4)(0.129)(Tf – 15.6...
Friday, October 21, 2016 by Dani

chemistry
A 0.1219-g sample of solid magnesium is burned in a bomb calorimeter that has a heat capacity of 1769 J/°C. The calorimeter contains exactly 271 g of water, and the temperature increases by 1.126°C. Calculate the heat given off by the burning Mg, in kJ/g and in kJ/mol.
Friday, October 21, 2016 by Dani

CHEMISTRY
write the orbital notation for the following set of quantum numbers n=1, l=0, m=0
Friday, October 21, 2016 by DAVID CHIRISWA

CHEMISTRY FOR ENGINEERS
What is the frequency and wave number associated with light of wavelength equal to 6000 angstrum
Friday, October 21, 2016 by DAVID CHIRISWA

Chemistry
Prepare 0.03 mole fraction solution of NaOH in water Total volume of solution is 100ml
Friday, October 21, 2016 by Faisal

Chemistry
You add 7.326g of solid CaCl2 to 45.5 mL of water in a coffee cup calorimeter and measure as the temp. Increase from 22.6 C to 41.5 C. Specific heat water is 4.184 J/ g.C and the density of water is 0.9977 g/mL. Find the mass of water. PLEASE HELP ME!!!
Thursday, October 20, 2016 by Dania

Analytical chemistry
Calculate to four decimal places the mass of purely dry MgCO3(Magnesium Carbonate) required to make 1L of a 1000 ppm Mg stock solution.
Thursday, October 20, 2016 by cindy

chemistry
How we make 0.02ppm solution in 25ml?
Thursday, October 20, 2016 by Usama munir

Chemistry
i need help making an acrostic poem using the word nonmetal
Thursday, October 20, 2016 by Josh

chemistry need help
Balance the following equation in an acidic and basic medium * Cr^(+3)+BrO^(-)--->CrO4^(2-)+Br^(-)
Thursday, October 20, 2016 by booob

CHEMISTRY
A lamp of marble chips was dropped in excess 0.1mol/dm hydrochloric acid and observed for sometime. (a) State what you would see. (b)Describe how the rate of reaction changed with time. (c)Explain why the reaction stopped after sometime. (d)The reaction was rather slow.State ...
Thursday, October 20, 2016 by BELDEN

chemistry
For the following reaction Co(g)+H2o(g)=Co2(g)+H2(g) If the initial concentrations of Co and H2o are 1.00 mol in a 50 L vessel, what is the number of mole of each species at equilibrium, if the equilibrium constant Kc= 0.85 at 1000 C? please can any one explain how to do this ?
Thursday, October 20, 2016 by b.k

Chemistry
I have a 0.6573g mixture of NaHCO3 and Na2CO3. Calculate the mass of NaHCO3 and Na2CO3 in the unknown mixture.Also calculate the mass of NaCl formed in the reaction of the mixture and HCl.
Thursday, October 20, 2016 by Sam

Chemistry
A 75.0g sample of liquid contains 17.5% by mass of H3PO4 (molar mass = 98.0g/mol). If 215.0mL of Ba(OH)2 is needed to completely neutralize the acid, determine the concentration of the Ba(OH)2 solution used
Thursday, October 20, 2016 by Biplob

Chemistry
Determine the mass of urea, CH2N2O, required to make 250mL of a 0.235 M solution
Thursday, October 20, 2016 by Lauren

Analytical chemistry
Calculate to four decimal places the mass of pure dry CaCO3 required to make 1 L of a 1000 ppm Ca stock solution.
Thursday, October 20, 2016 by Angel

Chemistry
Heat from burning a fuel is absorbed by a copper calorimeter. The calorimeter has a mass of 81.34 g and contains 200.0 g of water initially at 21 degrees Celsius. a) How much heat was absorbed by the calorimeter and the water if the final temperature of the water is 36.40 ...
Thursday, October 20, 2016 by lomonoyan

Chemistry
How much heat is required to melt 110g of ice at-45°C?
Wednesday, October 19, 2016 by Anna

Chemistry
What is the maximum mass, in grams, of NH3 that can be produced by the reaction of 1.0 g of N2 and 1.0 g of H2 using the reaction below? N2+H2→NH3 (not balanced) A) 0.60 g B) 5.7 g C) 1.2 g D) 2.9 g
Wednesday, October 19, 2016 by Katelyn

Chemistry
The number of moles of cl2 produce will be ??????? If one mole of pcl5 is heated at 250 in a vessel having a capacity of 10dm³.
Wednesday, October 19, 2016 by Nabiha

Chemistry
Magnesium oxide can be made by heating magnesium metal in the presence of oxygen. The balanced equation for the reaction is: 2Mg(s)+O2(g)→2MgO(s) When 10.1 g of Mg are allowed to react with 10.5 g of O2, 14.5 g of MgO are collected. a) Determine the limiting reactant for...
Wednesday, October 19, 2016 by Beth

Chemistry
What is the maximum mass, in grams, of NH3 that can be produced by the reaction of 1.0 g of N2 and 1.0 g of H2 using the reaction below? N2+H2→NH3 (not balanced) What is the maximum mass, in grams, of that can be produced by the reaction of 1.0 g of and 1.0 g of using ...
Wednesday, October 19, 2016 by Katelyn

chemistry
If 20 grams of zinc reacts with hydrochloric acid, how much zinc chloride is produced?
Wednesday, October 19, 2016 by sue

Chemistry
Assuming 100% dissociation, calculate the freezing point and boiling point of 2.45 m Na2SO4(aq). Constants may be found here sites. google. com/site/chempendix/colligative.
Wednesday, October 19, 2016 by Mia

  1. Pages:
  2. <<Prev
  3. 5
  4. 6
  5. 7
  6. 8
  7. 9
  8. 10
  9. 11
  10. 12
  11. 13
  12. 14
  13. 15
  14. 16
  15. 17
  16. 18
  17. 19
  18. Next>>

Homework Help: Science