Monday
August 29, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Calculate the maximum wavelength of light capable of removing an electron for a hydrogen atom from the energy state of n=4 if it requires an energy of at least 1.36 x10^-19 J to do this. I just want to know how to find the second n value so i can solve with rydeburgs equation??
Monday, February 22, 2016 by Maxx

Chemistry
The methane gas is formed by 25% hydrogen in mass which the ratio between the mass of carbon and hydrogen in this gas?
Monday, February 22, 2016 by Michael

chemistry
a.identity the phases that exist in a copper pan containing two iron nails ,a litre of water and four glass marbles b.A beaker contains clear, colourless liquid.How would you determine whether it contained dissolved table salt without tasting it? c. suggest a separation method...
Monday, February 22, 2016 by snothile

Chemistry
Calculate the maximum wavelength of light capable of removing an electron for a hydrogen atom from the energy state of n=4 if it requires an energy of at least 1.36 x10^-19 J to do this. Please help with formulas to use?
Monday, February 22, 2016 by Maxx

Chemistry
the longest wavelength of light that will cause an electron to be emitted from a metal is 520nm. what is the work function for this metal? (note: the work function is given as kJ/mole of electrons released)
Monday, February 22, 2016 by Jen

chemistry
If you begin with 0.030 L of a 2.5M NaOH solution, what concentration will you end up with if you dilute it to 0.050?
Monday, February 22, 2016 by Anonymous

chemistry
What volume of oxygen is required to completely combust 80 of butane
Monday, February 22, 2016 by perpetual

CHEMISTRY
find the concentrations of H+, HCO3-, CO3 2- in a 0.025M in H2CO3 solutions
Monday, February 22, 2016 by ADAM

CHEMISTRY
WHICH OF THE FOLLOWING IS TRUE FOR AN ACID? A. IT PRODUCES EFFERVESCENCE WITH BAKING POWDER. B. IT TURNS UNIVERSAL INDICATOR BLUE. Answer This Quest
Monday, February 22, 2016 by vidya

Chemistry
A compound has the empirical formula CHCL .A flask with volume 253 cm3 at temperature of 373K and pressure of 1.0 atm contains 0.8 g of the gaseous compound. Find the molecular formula of the compound.
Monday, February 22, 2016 by Amy

Chemistry
Why do warm temperatures speed up the fermentation of milk?
Monday, February 22, 2016 by Ali

Chemistry
2g AgCl is obtainded by adding an excess of AgNO3 solution to a solution containing 1g of a mixture of NaCl and KCl.What is the ratio of moles of two salts in the mixture?
Monday, February 22, 2016 by Anamika

Chemistry
The world record for a human holding their breath is 11 minutes, but most people can only hold it for a few minutes. If a women holds her breath at the maximum lung capacity (4.2 L), calculate the final pressure in her lungs, if her body temperature is 37.0 C and the ambient ...
Sunday, February 21, 2016 by Boberto

Chemistry
Calculate the following and write your answer in scientific notation 6.6 x 10^6 (8.8 x10^2) x (2.5 x 10^3)
Sunday, February 21, 2016 by Anonymous

Chemistry
How many grams of NaNO2 must be added to 1 liter of 1.00 M HNO2 solution in order to prepare a buffer solution with pH = 4.14? pH = 3.14? My work: ka = pH(buffer ratio) 4.5 * 10^-4 = 1.000*10^-4.14 (x M of base/1.00 M of acid) x = 6.21 6.21 M = (6.21 moles/1 L)(1 L) = 6.21 ...
Sunday, February 21, 2016 by Maddy

Chemistry
At what pressure would 0.150 mole of nitrogen gas at -23.0oC occupy 8.90 L? -23.o0c = 250 K P=(0.150 mol)(8.31 KPA x L/ K x mol)(250 K) = P is this right?
Sunday, February 21, 2016 by Boberto

Chemistry - Vapor Pressure
a.)What is the partial vapor pressure of a benzene above solution obtained by mixing 44.7 g benzene, C6H6, and 77.3 g toluene, C6H5CH3, at 25 ∘C? At 25 ∘C the vapor pressure of C6H6 = 95.1 mmHg; the vapor pressure of C6H5CH3 = 28.4 mmHg. b.)What is the partial ...
Sunday, February 21, 2016 by Anonymous

Chemistry
For the reaction between ammonia and hydrochloric acid to produce ammonium chloride; What volume of ammonia is used (at 20 Celsius and 760mmHg) if 12.5gmof ammonium chloride are produced in the reaction? How many molecules of ammonia does this represent?
Sunday, February 21, 2016 by Sam

chemistry
is it other than CH3COOH + C2H5OH => CH3COOC2H5 propanoic acid and isoamyl alcohol to make isoamyl propanoate?
Sunday, February 21, 2016 by ss

organic chemistry
is it anything other to form isopentyl propionate
Sunday, February 21, 2016 by ss

Chemistry
If the density of a gas is 1.2g/L at 745.torr and 20 Celsius, what is the molecular mass?
Sunday, February 21, 2016 by Sam

Chemistry
What is the density of NH3 at 800torr and 25 Celsius?
Sunday, February 21, 2016 by Sam

chemistry functional groups
Can a singly bonded CH2 group be classified as an alkyl or an alkane group? It's not the vinyl. Thanks!
Sunday, February 21, 2016 by Anonymous

chemistry
which alcohol and carboxylic acid would produce isoamyl propanoate by Fischer esterification
Sunday, February 21, 2016 by mm

Chemistry
When 6.0L of H2 reacts with 2.0L of N2, 4.0L of gaseous product are formed. All volumes of gases are measured at the same temperature and pressure. What is the formula of the product? Hint: Assume all reactants are consumed.
Sunday, February 21, 2016 by Cat

Chemistry
FB1 is a solution containing a mixture of potassium carbonate and sodium hydrogen carbonate . 25cm^3 of this mixture was to titrated against 0.250mol/dm^3 solution of HCL. In one titration using phenolphthalein as indicator, 10.00cm^3 of the acid was needed. In another ...
Sunday, February 21, 2016 by Diane

chemistry
WHICH OF THE FOLLOWING IS TRUE FOR AN ACID? A. IT PRODUCES EFFERVESCENCE WITH BAKING SODA B. IT TURNS UNIVERSAL INDICATOR BLUE.
Sunday, February 21, 2016 by vidya

Chemistry
Gasoline, which can be represented by the formula octane, bulk density is 704 g/l. To estimate the variation in enthalpy when burning 28.5 liters gasoline, based on the binding energies: 0 = 0 (117 kcal); C = 0 (173 kcal); 0 h (111 kcal); C-C (83 kcal); C-H (99 kcal)
Sunday, February 21, 2016 by Nayara

Chemistry
A 10.3g sample of an elemental gas has a volume of 58.4L at 758torr when the temperature is 2.5 C. Determine the identity of the gas.
Sunday, February 21, 2016 by Sam

Chemistry
Gasoline, which can be represented by the formula octane, bulk density is 704 g/l. To estimate the variation in enthalpy when burning 28.5 liters gasoline, based on the binding energies: 0 = 0 (117 kcal); C = 0 (173 kcal); 0 h (111 kcal); C-C (83 kcal); C-H (99 kcal)
Saturday, February 20, 2016 by Anonymous

chemistry
why hexane dissolved in toluene?
Saturday, February 20, 2016 by ben jackson

chemistry
The analysis of halogenated hydrocarbon gave the following results: A sample of mass m=255mg produces 273.7 mg carbon dioxide and 130.6 mg of water .A second sample of mass 87 is treated by hot molten sodium .The obtained mixture is dissolved in distilled water and filtered ....
Saturday, February 20, 2016 by vicky

Chemistry
a student found that the weight of the naphthalene collected was less than the weight determined by difference. what would account for the smaller amount of naphthalene collected?
Saturday, February 20, 2016 by Arif

Chemistry
How would you prepare a buffer (100ml) of pH 6.8 and concentration 0.1M given solid imidazole (mol wt.=68) and concentrated HCl
Saturday, February 20, 2016 by Tessie

Chemistry
which law of chemical combination is illustrated by the fact that 168 g of fe(iron) reacts with 72 g of water to form 232 g Fe3O4 and 8g H2
Saturday, February 20, 2016 by sajitha

AP Chemistry
Determine the pH of the following solutions. 1) 0.600 M HCl 2) 0.052 moles of H2SO4 dissolved in 4.2 L of water. 3)5.6 grams HNO3 dissolved in 450 ml of water. 4) 2.5 grams of NaOH dissolved in 500 mL of water. 5) adding 2 grams NaH dissolved in 0.56 L of water. 6) 20 mL of 0....
Saturday, February 20, 2016 by Tyra

AP Chemistry
Determine the pH of the following solutions. 1) 0.600 M HCl 2) 0.052 moles of H2SO4 dissolved in 4.2 L of water. 3)5.6 grams HNO3 dissolved in 450 ml of water. 4) 2.5 grams of NaOH dissolved in 500 mL of water. 5) adding 2 grams NaH dissolved in 0.56 L of water. 6) 20 mL of 0....
Friday, February 19, 2016 by Tyra

Chemistry
Gasoline, which can be represented by the formula octane, bulk density is 704 g / l. To estimate the variation in enthalpy when burning 28.5 liters gasoline, based on the binding energies: 0 = 0 (117 kcal); C = 0 (173 kcal); 0 h (111 kcal); C-C (83 kcal); C-H (99 kcal).
Friday, February 19, 2016 by Anonymous

Chemistry
1. Would it be advisable to determine the freezing point of pure p-dichlorobenzene with one thermometer and the freezing point of the solution with a different one? Explain. 2. If 0.150 mole of a nonvolatile non-electrolyte solute is present in 1200g of water, what are the ...
Friday, February 19, 2016 by Allie

Chemistry
what volume of 0.120 M NaOH must be added to 100 ml of 0.100 M NaHC2O4 to reach ph of 4.70? H2C2O4 Ka1 = 5.9 x 10-2 HC2O4^- Ka2 = 5.1 x 10-5 The answer is 60 ml but I dont know how to find it. Can you please show me the steps and how to do it please
Friday, February 19, 2016 by Steve

Chemistry-Dr.Bob 222
1. The rate constant for a second order reaction has units of L mol^-1 s^-1. What are the units of the frequency factor, A, for a second order reaction?
Friday, February 19, 2016 by Student

Chemistry
What is the required volume in ml to prepare a liter of solution 0.1 mol of nitric acid. molar mass 63 g / mol Density 1.41 g / ml, 75% weight by weight...
Friday, February 19, 2016 by Anonymous

chemistry!
what observations are made when you bubble chlorine into a solution of potassium iodide?
Friday, February 19, 2016 by laura

CHEMISTRY HELP
Calculate the amount (in mL) of 1.520M NaOH that is required to add the following acetic acid solution to prepare a buffer with the corresponding pH: 30.00mL of a 5.00% (w/v%) acetic acid; the resulting acetate buffer has a pH of 5.75. pKa of acetic acid = 4.74 So I got this: ...
Friday, February 19, 2016 by Mike

chemistry
An 11.1-g sample of CaCl2 is dissolved in 123 g water, with both substances at 24.0°C. Calculate the final temperature of the solution assuming no heat loss to the surroundings and assuming the solution has a specific heat capacity of 4.18 J/°C·g.
Friday, February 19, 2016 by Zelzin

Chemistry
Using the equation: 2C2H6 + 7O2--> 4CO2 + 6H20 How many moles of CO2 are produced by the reaction of 21.0 mol O2? Again, not sure how to write it correctly, but if I multiply 7O2 by 3, then I should do the same to the other side of the equation to make it 12CO2?
Friday, February 19, 2016 by Eric

chemistry
Calculate RAM of Cu and S from the percentage abundances of their isotopes Use your answers to find the RFM of Copper (II) Sulfide, Cus 63Cu- 69.1% 65Cu - 30.9% 32 Sulphur-95.0% 33 S-0.76% 34S-4.22% 35S-0.20%
Friday, February 19, 2016 by vidya

Chemistry
Using the equation: 2C2H6 + 7O2--> 4CO2 + 6H20 How may moles of 02 are needed to react with 4.0 mol of C2H6? I think the answer is 14, because if you double the C2H6 to make 4.0 mol, then in the equation you will need to double the O2 to 14. Is this correct?
Thursday, February 18, 2016 by Eric

Chemistry
Calculate the molal concentration. A 1% (w/w) solution of cocaine hydrochloride ( molar mass 339.81 g/mol) in water.
Thursday, February 18, 2016 by Student

CHEMISTRY PLEASE HELP APPRECIATE IT LOTS!
7.) How many moles of fluroine are required to react with 12 g of sodium iodide? I already balanced it but am confused to go from here F2 + 2 NAi ---- 2 NaF + I2 12 g NaI + 2 mol NAI/149.89 gNAi * 1 mol NAF/1 mol NAi * 1 mol F2 / 2 mol NaF 1.) how many grams of magnesium are ...
Thursday, February 18, 2016 by Anon

chemistry
A gas sample contained in a cylinder equipped with a moveable piston occupied 300.0 mL at a pressure of 2.00 atm. What would be the final pressure if the volume were increased to 500.0 mL at constant temperature? Answer should include units.
Thursday, February 18, 2016 by Kyra

Chemistry
An atmospheric scientist interested in how NO is converted into NO2 in urban atmospheres carries out two experiments to measure the rate of this reaction. The data are tabulated below. A: [NO]0 = 9.63 × 10-1 M, [O2]0 = 4.1 × 10-4 M t(s) 0/3.0/6.0/9.0/12.0 [O2] 4.1/...
Thursday, February 18, 2016 by Jesse

chemistry
calculate the valume of 200g og h2
Thursday, February 18, 2016 by monayem

Chemistry
what volume of 0.120 M NaOH must be added to 100 ml of 0.100 M NaHC2O4 to reach ph of 4.70? The answer is 60 ml but I dont know how to find it. Can you please show me the steps and how to do it please
Thursday, February 18, 2016 by Steve

Chemistry
Calculate solubility of AgCl (in g/L) in a 6.5*10^-3 M silver Nitrate solution ksp= 1.8 * 10^-10 (AgCl molecular mass is 143.3g) any idea on how to do this this is what i tried> AgCl--> Ag + Cl I 6.5*10^-3 0 C same x E same x ksp = [Ag][Cl] (1.8 * 10^-10) = (6.5 * 10^-3)...
Thursday, February 18, 2016 by Steve

Chemistry
Five grams of sodium are combined with unlimited bromine. How many moles of bromine are used up? How many liters of bromine would be used if the reaction took place at STP? My answer: .1088 mole Br2 and 2.44 L Br2
Thursday, February 18, 2016 by Anonymous

Chemistry
Calculate solubility of AgCl (in g/L) in a 6.5*10^-3 M silver Nitrate solution ksp= 1.8 * 10^-10 (AgCl molecular mass is 143.3g) any idea on how to do this this is what i tried> AgCl--> Ag + Cl I 6.5*10^-3 0 C same x E same x ksp = [Ag][Cl] (1.8 * 10^-10) = (6.5 * 10^-3)...
Thursday, February 18, 2016 by Steve

chemistry
If 15.22 g of mercury (II) oxide decompose, how many moles of oxygen can be produced?
Thursday, February 18, 2016 by jules

Chemistry
How many mL of 1.2 M HCl is needed to react with 5.8 g of Al(OH)3
Thursday, February 18, 2016 by Chris

Chemistry
how do i figure out "What is the energy of 1 mole of these photons" energy= 2.93x10^-19 wave length = 670.8 nm
Thursday, February 18, 2016 by Manny

CHEMISTRY
Calculate the amount (in mL) of 1.520M NaOH that is required to add the following acetic acid solution to prepare a buffer with the corresponding pH: 30.00mL of a 5.00% (w/v%) acetic acid; the resulting acetate buffer has a pH of 5.75. pKa of acetic acid = 4.74
Thursday, February 18, 2016 by Jeff

Chemistry
the atomic spectrum of lithium has a strong red line at 670.8 nm. what is the energy of each photon of this wave length? What is the energy of 1 mole of these photons?? -do you use the e=h x v ??
Thursday, February 18, 2016 by Cali

Chemistry
16. Aluminum chloride, AlCl 3, is made by treating scrap aluminum with chlorine. 2 Al(s) + 3 Cl2(g) → 2 AlCl 3(s) If you begin with 2.70 g of Al and 4.05 g of Cl2, (a) Which reactant is limiting?
Thursday, February 18, 2016 by Marine.t

Chemistry
I NEED HELP ASAP Here's the problem I'm struggling with: When 1.00 mole of ethlyene (C2H4) is burned at constant pressure, 1410 kJ of energy is released as heat. Calculate delta H for a process in which 10.0 g of ethlyene is burned at constant pressure. Please show me ...
Thursday, February 18, 2016 by Ian

Chemistry
Five grams of sodium are combined with unlimited bromine. How many moles of bromine are used up? How many liters of bromine would be used if the reaction took place at STP? My answer: .1088 mole Br2 and 2.44 L Br2
Thursday, February 18, 2016 by Anonymous

Chemistry
the atomic spectrum of lithium has a strong red line at 670.8 nm. what is the energy of each photon of this wave length? What is the energy of 1 mole of these photons??
Thursday, February 18, 2016 by Maxx

Chemistry
1) If I add 10 grams of salt into 0.1 L of water, what is the molarity of the solution? 2) Serial dilution is a common technique to make low concentration solutions. Each Serial Dilution involves taking half the solution and mixing it with a solvent, to halve the concentration...
Thursday, February 18, 2016 by Caitlyn

Chemistry 101
what is CAH2 + H20
Thursday, February 18, 2016 by Linda

chemistry
why does phosphorous and some other elements have two or more oxidation states
Thursday, February 18, 2016 by vidya

chemistry
Hcl is titrated against 5ml of sodium carbonate of strength 0.0133 then what should be the mean value of HCl added ?
Thursday, February 18, 2016 by Shareen

chemistry
a student was investigating the properties of a liquid L. He found that it turned phenolphthalein indicator red but when a piece of litmus paper was dipped into liquid L it turned blue. Which of these liquids could it be? a Aqueous ammonia b Lemon juice c copper sulphate ...
Thursday, February 18, 2016 by vidya

chemistry
based on your calculated rf values which cations formed weakly charged complexes
Thursday, February 18, 2016 by jawaher

chemistry
chlorine atoms have larger radii than fluorine A. True B. false I am unsure Answer Th
Wednesday, February 17, 2016 by sharon

CHEMISTRY!!!! HELP
3.) Calculate the mass of oxygen gas that can be produced in the decomposition of 5.55 g of silver oxide. This is what I did but is it right?... I need help with a few more btw to double check if i'm doing these right. So here is what I did: First: balance the equation 2 ...
Wednesday, February 17, 2016 by Sam

chemistry
Calculate the energy (in kJ) required to heat 25 g of liquid water from 25oC to 100.oC and change it to steam at 100oC. The specific heat capacity of liquid water is 4.18 J/goC, and the molar heat of vaporization of water is 40.6 kJ/mol.
Wednesday, February 17, 2016 by maria

science, chemistry
Calculate the final Volume of solution obtained if 100.0 mL of 12.0 M NaOH is diluted to 5.20M
Wednesday, February 17, 2016 by Amy

Chemistry
1.) what mass of zinc is needed to completely react with 4.00 g of silver nitrate? 2.) If excess ammonium sulfate reacts with 22.5 g of calcium hydroxide according to the following unbalanced chemical equation: (NH4)2 SO4 + Ca (OH)2 → CaSO4 + NH3 + H2O Now, how do I go ...
Wednesday, February 17, 2016 by Sam

Chemistry Help please! (:
Calculate the mass of oxygen gas that can be produced in the decomposition of 5.55 g of silver oxide. This is what I did but is it right?... I need help with a few more btw to double check if i'm doing these right. So here is what I did: First: balance the equation 2 Ag2 O...
Wednesday, February 17, 2016 by Sam

Chemistry
Please,tell me the ways I can use to understand chemistry better.I need help,and it is urgent because am starting to drop.
Wednesday, February 17, 2016 by Miracle

Chemistry
How many grams of salt can be produced from five grams of sodium and unlimited bromine? Is this 39.75 g NaBr?
Wednesday, February 17, 2016 by Anonymous

Chemistry
Okay so I understand this is incredibly unconventional, but I have a big favor to ask. I just got a chem exam back and my teacher still has not posted my scantron score. I was wondering if it is at all possible for you guys to just spot-check for accuracy. It can be rough or ...
Wednesday, February 17, 2016 by Justin

chemistry
What is the bond of a salt molecule? A. covalent B. hydrogen C. disulfide D. ionic I think A
Wednesday, February 17, 2016 by sharon

chemistry
S and O share chemical properties, but H2S is gas at room temp. and H2O is a liquid, why? A. H2O has stronger intermolecular bond B. H2S has a stronger intermolecular bond C. H2S has a stronger ionic bond D. H2O has a stronger ionic bond
Wednesday, February 17, 2016 by sharon

chemistry
The hands on a battery clock are which type of energy? A. chemical to kinetic B. potential to chemical C. kinetic to potential D. thermal to kinetic I think C
Wednesday, February 17, 2016 by sharon

chemistry
what is the percentage yield of c2h2 with 50g of cac2 reacts with water to yield 13.5g of c2h2
Wednesday, February 17, 2016 by francis

Chemistry
On a clear day at sea level, the partial pressure of N2 in air is 0.78 atm at 25 degres C. Under these conditions, the concentration of N2 in water is 5.3 x 10^-4 M. What is the partial pressure of N2 when the concentration in water is 3.5 x10^-4 M?
Wednesday, February 17, 2016 by Student

Chemistry
A solution is 0.10M in aqueous NH3. Calculate (a) the number of moles and (b) the number of grams of NH4Cl that must be added to 500mL of this solution to prepare a buffer solution with pH=9.15. You may neglect the volume change due to addition of solid NH4Cl. Kb=1.8x10^-5. (...
Wednesday, February 17, 2016 by Chen

Chemistry
I've worked through this problem so many times and I keep getting the same thing yet when I submit it, it says its wrong.. Am I missing something? Q:Calcium hydride (solid) reacts with water to form calcium hydroxide (aqueous) and hydrogen gas. Write a balanced chemical ...
Tuesday, February 16, 2016 by Chem: Troubleshooting

Chemistry
NaCl + H2O + CO2 + NH3 ______> NaHCO3 + NH4Cl 1) You dissolve an excess of NaCl in a solution containing 50.0 mL of 4.77 M ammonia. You bubble in an excess of CO2. Calulate the theoretical yield of sodium bicarbonate. I have no idea how to do this, can I know the step by ...
Tuesday, February 16, 2016 by eylow

chemistry
what does the spectrum of hydrogen tell us about its electrons?
Tuesday, February 16, 2016 by Mia

chemistry
why are there only certain colours in an atomic emission spectra?
Tuesday, February 16, 2016 by Emily

chemistry
assuming in the titration of NaCl and AgNO3, a student erroneously carried it out at a low PH,what effect will it be on the result. explain with an ionic equation
Tuesday, February 16, 2016 by Mina

chemistry
a piece of chalkboard dissolvedin acid solution and the solution bubbled vigorously.The gas caused barium hydroxide solution to form a white precipitate.what is the gas given off?what is the white precipitate?write a chemical equation for the formationof the white precipitate.
Tuesday, February 16, 2016 by semisi caucau

chemistry
what is thiosulphate
Tuesday, February 16, 2016 by Timmy

Chemistry
why is chemistry needed
Tuesday, February 16, 2016 by Timmy

Chemistry: stoich
4. Suppose that an excess of propane, C3H8 , burns in 320 g of oxygen, How many moles of water will be formed? C3H8 + 5 O2 --> 3 CO2 + 4 H2O (1 point) 6.02 E 23 moles 1600 moles 4.0 moles 8.0 moles
Tuesday, February 16, 2016 by Hannah

Chemistry
5. How many grams of iron oxide can be produced from 2.50 g of oxygen reacting with iron, according to the following equation? 2 Fe (s) + 3 O2 (g) -->2 Fe2O3(s)
Tuesday, February 16, 2016 by Hannah

Chemistry
5. How many grams of iron oxide can be produced from 2.50 g of oxygen reacting with iron, according to the following equation? 2 Fe (s) + 3 O2 (g) -->2 Fe2O3(s)
Tuesday, February 16, 2016 by Hannah

Chemistry
Describe how you would distinguish between solutions NH4Cl and NaCl using litmus paper
Tuesday, February 16, 2016 by Miracle

Chemistry
how to separate a mixture of iron filings, salt, sand and wood chips.
Tuesday, February 16, 2016 by Jojo

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Homework Help: Science