Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
An hydrogen atom in the ground state absorbs a photon with a wavelength one and after release a photon with a wavelength two,on which orbital will drop the electron?

chemistry
Identify the element that has a ground state electronic configuration of [Ar]4s23d104p 4

Chemistry
The equation is N2 + O2 reacts 2NO Given 12.5 mg of oxygen reacts with 21.4 mg of Nitrogen what mass of product is formed

chemistry
Pl help...what are the isomers of chlorodibromobenzene

Chemistry
Oxalic acid, found in the leaves of rhubarb and other plants, is a diprotic acid. H2C2O4 + H2O ↔ H3O+ + HC2O4- Ka1= ? HC2O4- + H2O ↔ H3O+ + C2O42- Ka2 = ? An aqueous solution that is 1.05 M H2C2O4 has pH = 0.67. The free oxalate ion concentration in this solution is [C2O42...

Chemistry
What volume (in mL) of 1.0 M HCl is required to prepare 500 mL of pH 7.76 buffer using triethanolamine that is 0.020 M in both triethanolamine and triethanolammonium ion?

Chemistry
When coal is burned, the sulfur it contains is converted into sulfur dioxide. This is SO2 is a serious pollutant, so it needs to be removed before it escapes from the stack of a coal fired plant. One way to remove the SO2 is to add limestone, which contains calcium carbonate, ...

Chemistry
A precipitation reaction takes place when a water solution of potassium phosphate, K3PO4, is added to a water solution of cobalt (II) chloride, CoCl2 Write a balanced equation for this reaction

Chemistry
Potassium permanganate, KMnO4, a common oxidizing agent, is made from various ores that contain manganese (IV) oxide, MnO2. The equation shows the net reaction for one process that forms potassium permanganate 2MnO2+2KOH+O2=2KMnO4+H2 Explain why the oxygen gas is in excess

Chemistry
Potassium permanganate, KMnO4, a common oxidizing agent, is made from various ores that contain manganese (IV) oxide, MnO2. The equation shows the net reaction for one process that forms potassium permanganate 2MnO2+2KOH+O2=2KMnO4+H2 What is the maximum mass, in kilograms, of ...

Chemistry
Hydrogen gas is used for many purposes, including the hydrogenation of vegetable oils to make margarine. The most common industrial process for producing hydrogen is "steam reforming," in which methane gas, CH4, from natural gas reacts with water vapor to form carbon monoxide ...

Chemistry
Hydrogen gas is used for many purposes, including the hydrogenation of vegetable oils to make margarine. The most common industrial process for producing hydrogen is "steam reforming," in which methane gas, CH4, from natural gas reacts with water vapor to form carbon monoxide ...

Chemistry
Hydrogen gas is used for many purposes, including the hydrogenation of vegetable oils to make margarine. The most common industrial process for producing hydrogen is "steam reforming," in which methane gas, CH4, from natural gas reacts with water vapor to form carbon monoxide ...

Chemistry
Elemental analysis of a compound, once used as a pesticide, was found to be 74.2% carbon, 8.64% hydrogen, and 17.2% nitrogen. This compound has a molecular mass of 162.23g/mol, what is the molecular formula for this compound?

Chemistry
Which reaction below represents the second ionization of Lr?

chemistry
what are the isomers of chlorodibromobenzene

Chemistry
Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. Calculate the density of CaF2 from these ...

Chemistry
What are the isomers of chlorobromobenzene

chemistry
Determine the mole fraction of lithium bromate in a 6.32 M aqueous solution of lithium bromate. The density of the solution is 1.16 g mL-1. I understand that 6.32 M of solution= mols of the compound. I multiplied 1000mL by the density to get grams. I don't know what to do next.

Chemistry
Use the calculation of specific heat for your metal as an example and determine the effect on specific heat if the sample temperature is changed. Does this small loss in heat significantly (>5%) affect your value for the specific heat of the metal? How would I solve this? ...

Chemistry
What is the molarity of the final solution if 2.00mL of the 5.00 M stock solution is diluted to 10.00mL to make solution A? Solution A then undergoes a second dilution by taking 3.00mL solution A and diluting it to 25mL.

chemistry
nitrogen and hydrogen react to form ammonia. N2+3H2=2NH3. 12 dm3 of hydrogen reacted with excess nitrogen to form 2 dm3 of ammonia. what is the percentage yield of ammonia at room temperature and pressure

chemistry
Enthalpy of combustion of c(graphite)is _393.3 KJ mol -1then for producing 39.3 KJ of heat the amount of carbon required is

Chemistry
Give a simple test that would allow you to distinguis between the following pairs of anions. Tell what you would do and what you should observe for each anion. A. CO3^2- and SO4^2- B. Cl- and SO4- C. CO3^2- and Cl- Now, for each cation A. B^3+ and Ca2+ B. Ca^2+ and Sr+ C. Ca^2...

Chemistry
How many milliliters of water at 25.0°C with a density of 0.997 g/mL must be mixed with 165 mL of coffee at 91.0°C so that the resulting combination will have a temperature of 62.1°C? Assume that coffee and water have the same density and the same specific heat (4.18 J/g...

Chemistry
Are the units for frequency Nu or Hz????????!

Chemistry
Does anyone know the answers to the Chemistry unit 4 lesson 11 ( Chemical Bonding ) test ?? In 11th grade

Chemistry (Mass/volume)
What are factors that will contribute to achieving the lowest mass/volume ratio possible for an airbag? The "mass" includes the mass of the reactants, bag, and any additional materials you would use to make the airbag. The "volume" is of the inflated air bag.

Chemistry
One third of vanilla ice cream provides about 145 kcal of energy. A typical adult uses about 195 kcal/hr of energy while walking. If all of the energy in one third of a cup of vanilla ice cream were to be burned off by walking, how many minutes would it take for this energy to...

Chemistry
Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. Calculate the density of CaF2 from these ...

Chemistry
What is the mass in grams of a 15.8 L sample of ozone (O3) at 1.67 atm and 30.0 °C?

Chemistry
What volume of dry NO at 25°C and 1.00 atm can be prepared by reacting 6.35 g of Cu with 25.0 mL of 6.0 M nitric acid, HNO3? 3 Cu(s) + 8 HNO3(aq) --> 3 Cu(NO3)2(aq) + 2 NO(g)+ 4 H2O(l)

Chemistry
When 20 grams of calcium carbonate decomposes, how many grams of calcium oxide are produced?

Chemistry
This compound has a molecular mass of 1268.06g/mol, what is the molecular formula for this compound?

Chemistry
What is Enthalpy?

chemistry
I post this question two time before but the degree sign is wrong so I post this one with everything corrected for the final time. Thank upon who answer this question on the other 2 same question before. Calculate the final temperature that results from mixing 245 grams of ...

chemistry
Calculate the final temperature that results from mixing 245 grams of cobalt, specific heat 0.446 J/g0C, at 1420C with 106 grams of water at 24.80C.

Chemistry
How much mg of iron are there in 100g of spinach. if we burned 5.20g of spinach and added 10 ml of 2.0 M HCl into the spinach ashes.Then filtered the ashes and used 5 ml of that solution to put it in a testube and added 5 ml of 1.5 M KSCN in the testube. We then use a ...

Chemistry
Calcium Fluoride, CaF2, adopts the fluorite lattice, which is described as a face-centered cubic array of Ca2+ ions with F-1 ions with Ca2+ ions in half of the cubic holes. The Radii of Ca2+ and F-1 are 126 and 117 pm, respectively. Calculate the density of CaF2 from these ...

chemistry
Blue copper sulfate pentahydrate (CuSO4.5H2O) crystals were heated to give the white monohydrate. What percentage of water was lost? (molar mass of CuSO4.5H2O is 250.5 g/mol)

Chemistry
A synthesis yielded 222g of phosphoric acid. How many moles of phosphoric acid were produced? I keep dividing 222g/98g (molar mass) which gives me 2.265. Every time I put the answer in, it tells me I am wrong.

Chemistry
What is the value of [h3o] in a solution where [oh]=4.20x10^-6

Chemistry
If 4.00g of iron metal are reacted in a calorimeter with a heat capacity of 500J/ degree Celsius, what would be the final temperature of the calorimeter if its initial temperature were 23.0 degree Celsius?

chemistry
The average molar mass of a natural gas is 17.4g/mol consisting of CH4 and C2H6,what is the molar fraction of each gas?

Chemistry
Potassium chlorate, KCIO3, acts as an oxidizing agent in matches, explosives, flares, and fireworks. In the equation below, it is formed from the element chlorine and potassium hydroxide. 3 Cl2+ 6KOH=KCIO3+5KCL+3H2O Write a conversion factor that could be used to convert ...

Chemistry
In 1985 benitoite became the California "state gemstone." Found only in a tiny mine near Coalinga, California, it is a silicate of barium and titanium with trace impurities that cause a range of hues from colorless to blue to pink. Its general formula is BaTi(SiO3)3. If a 15 ...

Chemistry
An analytical chemist weighs out 0.225g of an unknown diprotic acid into a 250mL volumetric flask and dilutes to the mark with distilled water. He then titrates this solution with 0.0700M NaOHsolution. When the titration reaches the equivalence point, the chemist finds he has ...

Chemistry
What is final temperature of a 88 gram sample symbol of water at 295 k that absorbs 1250 Joules of heat ?

Chemistry
A 1 g sample of water at 373 K is cooled by the removal of 100 J . what will be the final temperature of the water

Chemistry
What mass of water in Gram can be heat from 300 K to 315 K by addition of 600 Joules of heat ?

chemistry
A process is carried out at constant pressure. Given that ΔE is positive and ΔH is negative, Select one: A. the system absorbs heat and contracts during the process. B. the system absorbs heat and expands during the process. C. the system loses heat and contracts during the ...

chemistry
Zinc reacts with sulphur to form zinc sulphuric 16.2g.Sample of zinc is reacted with log of sulphur(Zn=65,S=32,o=16) A)Write a chemical reaction for the reaction b)Calculate the number of moles of zinc atoms that reacted. c)Number of moles of sulphur atoms that reacted

Chemistry
What problems might arise if the anesthesiologist did not know the patient's higher body temperature?

chemistry
Calculate the final temperature that results from mixing 245 grams of cobalt, specific heat 0.446 J/g0C, at 1420C with 106 grams of water at 24.80C.

Chemistry
Use two concentration tables to calculate the concentrations of the species present in a 0.0400 M solution of CsBrO. a.[HBrO] b.[BrO-] = 0.0400M c. [H3O+] d.[OH-] hi. how would I attempt this problem. can you walk me through it or give me a hint.

chemistry
stoichiometry problem Fe2O3+HCl=H2O+FeCl3 If 42.2 grams of iron(III) Oxide react with HCl how many gramd of iron(III)chloride should be produced

Chemistry
A student determined the calorimeter constant of the calorimeter. The student added 50.00 mL of cold water to 50.00 mK of heated , distilled water in a styrofoam cup. The initial temp of the cold water was 21,00C and the hot water, 29.15C. The maximum temp pf the mixture was ...

Chemistry
For a 0.47 M solution of LiClO compute the pH. Hi. I am confused about this question. I calculated the pH...but my answer is wrong. what am I doing wrong??? pH=-log(0.47) pH=0.33

Chemistry (molarity) (sorta an emergency)
I'm doing a titration lab and writing a lab report where I'm sort of stuck on how exactly to find the concentration of HCl. These are the following info I have from the lab, Equation: HCl(aq)+NaOH(aq)-> H2O(l)+NaCl(aq) -Calculated molarity of NaOH solution is .103M -Volume ...

Chemistry
Normal glucose levels in the blood are from 70 to 110 mg glucose per 100mL of blood. If the level falls to low, there can be brain damage. If a person has a glucose level of 92 mg/ 100mL, what is the total mass of glucose in grams in 5.10 L of blood?

Chemistry
When you try to leave your room you learn that the only door out is locked. Assuming there is no air flow into the room (air tight with no ventilation system) how long can you survive in the room (5 meters long, 5 meters wide, 5 meters high) -Human tidal volume (volume of air ...

Chemistry
Elemental analysis of a compound, once used as a pesticide, was found to be 74.2% carbon, 8.64% hydrogen, and 17.2% nitrogen. What is the empirical formula of this compound?

Chemistry
November's birthstone is citrine, a yellow member of the quartz family. It is primarily silicon dioxide, but small amounts of iron(III) ions give it its yellow color. A high quality citrine containing about 0.040 moles of SiO2 costs around $225. If this stone were pure SiO2, ...

Chemistry
There are about 1 x 10^5 chemical reactions per second in each of the 10 billion nerve cells in the brain. How many chemical reactions take place in a day in a single nerve cell?

Chemistry
Compare the energy needed to raise the temperature of 1kg of water from 20°C to 100°C and the energy needed to boil 1kg of water at 100°C? I turned 1kg to 1000g water is 4.18J/g°C and subtracted 20°C then i get confused as what to do next to

Chemistry
How many electrons in an atom could have these sets of quantum numbers? n=2 n=5, l=3 n=6, l=1, ml=-1

chemistry limiting reagent
if i have a 1:1 mole ratio as with this reaction: NaOH + HCl --> NaCl + H20 and i use same volumes (50mL) and same Molaritys (1.00M) then there is no limiting reactant correct??

chemistry
Is this balanced properly 2H2O2----> 2H2O +O2 Thank you for the reactions of zinc and acetic acid. REAL QUESTION, if I was to rub all the copper off of a new penny down to the zinc, what would be the appearance of the zinc if I left it in vinegar (acetic acid ) for 30min. I...

chemistry
Assume that it is necessary to determine the [FE^3+ in a solution that may be 0.0001 to 0.0005 M range . Outline the spectrophotometric method that would accurately give the required data. Be spectific about the solutions that you would use. I know I have to work up a ...

chemistry
Dr Bob, Sorry about this penny thing, but if I was to put pure zinc into acetic acid, what would happen to the zinc?

Chemistry
A chemist takes a 647 gram sample of this hydrate. She removes all the water possible from the sample and collects it. To this water, she adds 7.6 grams of lead(II) nitrate. Afterwards she wants to precipitate all the lead. She wants to use a solution of aluminum sulfate to ...

Chemistry
will a precipitate form when 650 ml of 0.008 K2So4 is added to 175 ml of AgNo3 Ksp of Ag2So4=1.5*10^-5 Can any one tell me how to do it >? please

Chemistry
I am really having a hard time doing this question. We were asked to determine the iron content of spinach in a solution. We burned a 5.50g of spinach and added 10 ml of 2.0 M HCl in the spinach ashes. We mixed that and filtered the solution to removed the ashes. We used 5 ml ...

chemistry
Calculate the no.of moles (a)3.011 X 10power 23 atoms of He (b)1.505 X 10power23 of Co2 (c)6.022 X 10power23 atoms of Na (hint :nis equal to N/No)

Math (Algebra)
A chemistry student needs to make 60 liters of a 30% alcohol solution. He has a 20% alcohol solution and a 40% alcohol solution in the lab. How many liters of each strength does he need to mix together *The system of equations I did was: a+b=60 & .2a+.4b=18. I may be wrong but...

Chemistry
What is the minimum volume of 2.00 M hydrochloric acid necessary to neutralize completely the hydroxide in 800.0 mL of 0.3 M calcium hydroxide?

Chemistry
One-third cup of vanilla ice cream provides about 145 kcal of energy. A typical adult uses about 195 kcal/hr of energy while walking. If all of the energy in one third of a cup vanilla ice cream were to be burned off by walking, how many minutes would it take for this energy ...

Chemistry
How many mL of acetone are required to make a 8.42 % v/v aqueous solution in a 300 mL volumetric flask?

Chemistry
How many Cu+2 ions are in 5.33 mol of CuCl2? I did this so far: n-> 5.33 mol Ncu-> ? ions M= 134.45 g =5.33 mol x (602x10^23 ions/ 1 mol) =3.21x10^24 ions

Chemistry
Copper (I) chloride, CuCL, has Ksp = 1.9 x 10^ -7.calculate the molar solubility of CuCL in A)pure water, B)0.0200M HCl solution C) 0.200M HCl solution, and d) 0.150M CaCl2 solution. I used the ice table and for a) i got 0.000435 M sort of lost for the rest

chemistry
If 200. mg of fluorine-18 is shipped at 7:00 A.M., how many milligrams of the radioisotope are still active when the sample arrives at the radiology laboratory at 4:10 P.M.?

chemistry
the word "proof" on alcoholic beverages is defined as twice the percentage by volume. How many ml of alcohol are in a one-liter bottle of 80-proof gin?

chemistry
how much solute are present in a solution that contains 100.0g of water, and is 9.0% by weight sodium bicarbonate?

chemistry
how many grams of potassium nitrate are needed to prepare 250.0ml of a 0.03M potassium nitrate solution?

chemistry
calculate what volume of sulfuric acid solution(specific gravity=1.07;and containing 10%sulfuric acid by mass)contains 18.50g of pure sulfuric acid at a temperature of 25 Celsius.

chemistry
what volume of a 0.20M potassium sulfate solution contains 57g potassium sulfate?

chemistry
Suppose 5 ∫ f(x)dx=6 ∫ 2 3 ∫ f(x)dx=1 ∫ 2 5 ∫ f(x)dx=4 ∫ 4 4 ∫ (6f(x)−1)dx= ? ∫ 3 help, please? I got the answer of 5, but it says its wrong

Chemistry
Consider the neutralization reaction that takes place when hydrochloric acid reacts with aqueous calcium hydroxide Write a complete balanced equation for this reaction

chemistry
how much CuSo4•5H2O will precipitate from a aq. soln of CuSO4, 25g dissolved in min amnt of water at 60C then cooled at 0C. Solubility of CuSO4 at 60C in 100 mL H2O is 40 g and in 0C is 15g.

Chemistry
1) how many joules are required for each of the following? A)Heating 55g of water from 12 degree Celsius to 76 degree Celsius B) Melting 12.8g of ice at 0 degree Celsius. c) Boiling 21.1 g of water at 100 degree Celcius

chemistry
At 25ºC and 1 atmosphere the following equilibrium is eatablished : 2NO (g) <=> N2O4 (g) The partial equilibrium pressure of N2O4 is 0.7 atm. A) calculate Kp of the above system at 25ºC. B) calculate the partial pressure of the above two gases at equilibrium when the ...

chemistry
when a quantity of powdered sulphur is burnt in excess oxygen, 100cm3 of SO2 were produced at STP CAL,the vol of gas at STD

Chemistry
Determine the mass of iron in the following solution. 325mL of 0.050 M FeSO4.

Chemistry
Determine the mass of iron in the following solution. 325mL of FeSO4.

Chemistry
Nitrogen (80 kPa), oxygen (21.0 kPa), carbon dioxide (0.03 kPa), and water vapor are the usual components of air. What is the partial pressure of water in mm Hg if the total atmospheric pressure in 1.00 atm?

Chemistry
What is the solute-solvent interaction between silver nitrate in water?

Analytical chemistry
Why HNO3 only can used for acidification in volhard method not other acids like HCl or H2SO4?

Chemistry (molarity)
How would I find the moles of NaOH solution that was used to titrate? I have 20.01mL of HCl used and 15.95mL of NaOH solution was used to titrate.

Chemistry
What is the molarity of the final solution of 2.00mL of the 5.00M stock solution is diluted to 10.00mL to make solution A. Solution A undergoes a second dilution by taking 3.00mL solution A and diluting it to 25mL? I'm so confused by this. Please help.

Chemistry
Explain how a ligand can be both sigma donating and pi donating and give an example of a ligand that does both. Is this ligand a Lewis acid or a Lewis base? Thank you!

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Homework Help: Science