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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
E=hc/lambda How would I rearrange this to be able to solve for the other variables (c or lambda)??????? Please and thank you.

Chemistry
Based on my percent error (65.8%), would this method of testing for iron be considered a valid means of determining iron content in vitamin pills? Why or why not? I don't understand how to fully answer this question. Since my percent error is high, would it be considered ...

Chemistry
What size volumetric flask do you need to dilute a 0.150M NaOH to 0.390M if you pipette 1500ml?

CHEMISTRY
Why would it be better to use lighter colored lights (like yellow) be used in a spectroscopy experiment, rather than a green colored light? If green is used instead of yellow, would absorbance values be higher or lower? I don't understand :(

Chemistry
This question refers to spectroscopy. So why are certain colors used in this experiment? For example, why would a yellow light be used instead of a green light? And if I were to use a green light instead of a yellow light, would absorbance values be higher or lower?

Chemistry
When We Balance Equations In Chemical Reaction,we Are Obeying The Law Of

Chemistry
If you do percent error and you come up with about 70% error, would this method of testing be considered valid? Why or why not? I don't understand an actual reason to use.

Chemistry (Molarity) Help
So there's this prelab assignment we're supposed to complete where we would fill out this table with [FeSCN^2+] in each of the test tubes. I'm not completely sure on how to do this? For example, on the first tube calculate the molarity of [FeSCN^2+] with the data given: -...

Chemistry
How do differences in molar absorptivity and cell pathlength change the absorbance of a measurement?

Chemistry (Dilution) Help please?
Calculate how to prepare 100.0mL of a 1.25x10^-4 M aqueous solution of Fe(NO3)3(aq) by dilution of stock of 0.0025M Fe(NO3)3(aq) in a 100.0mL volumetric flask? I tried using the m1v1=m2v2 equation but it doesn't look like that equation would work for this problem??

chemistry
Find the volume of carbondioxide produced when 25grams ofCalcium carbonate was completely burnt

chemistry
Find the volume of carbondioxide produced when 25grams ofCalcium carbonate was completely burnt

Chemistry
2 balloons A and B of volume 600 ml and 1000 ml are taken at temperature 400 K. Max capacity of balloon A and B are 800 and 1200 ml resp. When the temperature is raised which balloon will burst first ?

chemistry
why is the spectrum of hydrogen composed of discrete lines?

Chemistry
Calculate the ph value after of 1ml of 0.01 mol/1hcl solution to 1 liter of distilled water that is initially at ph=7

Chemistry
How much water at 10°C can be heated to 40°C by the heat evolved from cooling 300g of water from 80°C to 40°C?

Chemistry
What is the pH of a 0.36% by mass HCl?(density=1.0 g/mL)

Chemistry
Ammonium nitrate a common fertilizer was used by terrorists in the trgic explosion in oklahoma city in 1995.how many litres of gas at 307oc and 1.00atm are formed by the explosive decomposition of 15kg of ammonium nitrate to nitrogen, oxygen and water vapour Solution 2NH4NO3=...

Chemistry
If a box contain 256 water molecules and 1 Na+ ion , then what will be the Molarity of the solution.

chemistry
Identify the species oxidized, the species reduced, the oxidizing agent and the reducing agent in the following electron transfer reaction. 2Fe3+ + Sn2Fe2+ + Sn2+ species oxidized species reduced oxidizing agent reducing agent As the reaction proceeds, electrons are ...

chemistry
The following information is given for ether, C2H5OC2H5, at 1atm: boiling point = 34.6 °C Hvap(34.6 °C) = 26.5 kJ/mol specific heat liquid = 2.32 J/g°C At a pressure of 1 atm, kJ of heat are needed to vaporize a 41.0 g sample of liquid ether at its normal boiling point of ...

Chemistry
If the change in temperature of a sugar added solution of water increased its boiling point by 0.6C how many moles of sugar was added to the water?

Chemistry
A minimum energy of 151 kJ is required to dissociate a mole of iodine molecules, I2. Calculate the wavelength of radiation that supplies this energy, assuming each bond beaks by absorbing one photon.

Chemistry
The maximum number of PbO molecules that can be injected is 3.01 x 10*23 1.) How many moles of PbO can be injected? 2.) What mass of PbO can be injected?

Chemistry
Which of the following gases has the highest average speed at 400K? NO2 OF2 SO2 SF6

Chemistry
At 298 K which is larger rate of effusion or rate of diffusion?

Chemistry
A 5.00-L flask contains nitrogen gas at 25°C and 1.00 atm pressure. What is the final pressure in the flask if an additional 2.00 g of N2 gas is added to the flask and the flask cooled to -55°C?

Chemistry
If 3.42 grams of Al2(SO4)3 are required, what mass of H2SO4 must be present?

Chemistry
Write an equation for the oxidation of NH2OH to HNO3 by KBrO3. Balance the reaction equation using the ion-electron method.

Chemistry 20
Lab: Determining the Quantity of Vitamin C in Fruit Juice Vitamin C, also called ascorbic acid, is commonly found in commercial fruit juices and drinks. In this activity you will analyze data collected from a titration analysis of a fruit juice. The nutrition facts for a 200-...

Chemistry
If you try to carry out a double displacement reaction by mixing together equal volumes of a solution that contains dissolved NaF and a solution that contains dissolved NaCl. Would you expect a reaction? Why or why not?

Chemistry
Hi, wondering if anyone can help with the following problem: A solution of NH3 (kb=1.8x10^-5) has a ph of 11. what is the molar concentration of NAOH? I am unsure how to go about this however i have tried [10^-3][10^-11]/ 1.8x10^-5 with no success. Thanks for your help

chemistry
Calculate the formula of a compound which has composition. MaMagnesium 9.8%,sulphur 13%, oxygen 26%,water of crystallization 51%. (Mg=24,S=32,O=16,H2O=18g/mol)

Chemistry
Why we add HCL ot H2SO4 during the experiment Of iodometry?

chemistry
A bottle of cabernet sauvignon wine contains 12.5% v/v ethanol. How much ethanol will be present in a dozen 750 mL bottles of this wine?

Chemistry
I am trying to answer the question below, and I am guessing the reason lactate has a lower Km is that it is better able to accept electrons than ethanol. Is this correct? If so, what makes lactate a better electron acceptor? Any help is greatly appreciated! "ethanol is a very ...

Chemistry
A sample of Chlorine occupies 8.50 L at 80.0 C and 740 mm Hg. What volume will Chlorine occupy at STP?

Chemistry
I need to find the pH of a 500 mL solution of pure water after adding 33.0 mg of H2SO4 and 18.0 mg of HCl. Please help! So far I have tried to find the moles of 33.0mg of H2SO4 and got 3.24. Then I calculated pH by multiplying the subscript of H (2) by the moles (3.24) and ...

chemistry
estimate the enthalpy change for the following reaction: OF2 + H2O = O2 + 2HF

Chemistry
What volume of hydrogen, reacting with nitrogen, will produce 500 dm^3 of NH3 at STP?

Chemistry
why does chlorobenzoic acid have a lower freezing point than benzoic acid explain? would this have something to do with the intermolecular forces or polarity. I know that the chlorobenzoic acid a Cl atom in the molecule which would create for a stronger intermolecular force ...

Chemistry
In Cl2 + 2KBr -> 2KCl and Br2 produce that brown yellow effect?

chemistry
what is the purpose of using an ice bath in organic chemistry when isolating the final product?

Chemistry
What mass of calciumoxide is formed by heating Ca(iii)oxocarbonate(iv) when calcium = 40, carbon = 12, oxygen = 16

CHEMISTRY
HOW TO PREPARE 1 M GUAICOL FROM LIQUID GUAICOL SOLUTION MOLECULAR WEIGHT 124.14 DENSITY 1.11

Chemistry
Among the solubility rules previously discussed is the statement: Carbonates, phosphates, borates, and arsenates—except those of the ammonium ion and the alkali metals—are insoluble. (a) Write the expression for the equilibrium constant for the reaction represented by the ...

Chemistry
hen excess Ag metal is added to 0.246 L of 1.290 M Fe3+(aq) at 298K, the following equilibrium is established: Ag+(aq) + Fe2+(aq) Ag(s) + Fe3+(aq) (1) If the equilibrium concentration of Ag+ is 0.504 M, what is the value of K? K = (2) Using the value of K from part (1), ...

Chemistry
calculate the concentrations of H2S04, H30+, HSO4- and SO42- in 0.4 M H2S04 solution

chemistry
why half cell reactions are given in reduction reations by IUPAC?

Chemistry
What volume of 0.1244M hydrochloric acid is required to neutralize 24.81 ml of 0.1026M barium hydroxide? from the mole to mole ratio and the given information I came up with .00509 mols of HCl. would I multiply this by 0.1244 or divide by .1244. I'm not sure which would be ...

Chemistry
If there are 10 groups performing an experiment and each group needed 25.0 mL of 0.250 M NaOH, how would you prepare the NaOH solution for the whole lab using the NaOH pellets?

chemistry
CH4+2O2-->CO2+2H2O If 22.75g of carbon dioxide is obtained when 9g of methane is burned in excess oxygen, what is the percent yield? Show work too please

chemistry
2Na+2H2O-->2NaOH+H2 what is the mass of reactant left over? pls show work too thank you

Chemistry
The equilibrium constant, K, for the following reaction is 1.54×10-2 at 506 K: PCl5(g) PCl3(g) + Cl2(g) An equilibrium mixture of the three gases in a 15.7 L container at 506 K contains 0.207 M PCl5, 5.64×10-2 M PCl3 and 5.64×10-2 M Cl2. What will be the concentrations of ...

chemistry
Cu+HNO2-Cu(NO3)2+NO solved by oxidation no. Method

Chemistry
h2po4(aq) + co34(aq) hco3 (aq) + hpo42 (aq)

chemistry
if i have an isopropyl group and the a carbon with a methyl group on it, will the methyl protons be split by the isopropyl protons? (CH3)2---C-C-(CH3)

chemistry NMR helpppp
really really need some help, been stuck on this for toooo long. Some Data: "A" triplet for 3H (2 neighbors) "B" quartet for 2H (3 neighbors) "C" singlet for 3H (no neighbors) "D" singlet for 2H (no neighbors) Alright here is what i have so far: im trying to figure out what ...

chemistry
The number of unpaired electrons and the element for [Xe]6s24f145d7: I know the element is Iridium but I cannot figure out the unpaired electrons!

Chemistry
the solubility of aspartic acid in water is .500 g in 100 mL at 25 degrees C. If .251 g of aspartic acid is dissolved in 50. mL of water at 50 degrees C and let solution cool to 25 degrees C. is the solution supersaturated, saturated, or unsaturated. the solution was not ...

Chemistry
Why does the white precipitation turns dark when adding Na2S2O3 drop wise to AgNO3 sollution

Chemistry
A reaction of hydrolysis of Ba(NO) in a net ionic form?

Chemistry
How long must a steady current of 4.0A flow through the electrolyte to coat a a steel spoon with 8.5g of nickel?

Chemistry
Carbohydrates (such as C6H12O6) undergo combustion with oxygen to produce carbon dioxide and water. Living things use this reaction (a process called respiration) to produce energy. Determine the mass of carbohydrates consumed for every 0.300 mol of oxygen gas consumed during ...

Chemistry
Carbohydrates (such as C6H12O6) undergo combustion with oxygen to produce carbon dioxide and water. Living things use this reaction (a process called respiration) to produce energy. Determine the mass of carbohydrates consumed for every 0.300 mol of oxygen gas consumed during ...

AP Chemistry
Calculate the concentration of the constituentions in solutions of the following compounds in the following concentrations: (a) 0.45 M HBr, (b) 0.045 M KOH, (c) 0.0112 M CaCl2.

Chemistry
In the dehydrogenation of ethane two reactions take place: C2H6 => C2H4 + H2 C2H6 + H2 => 2CH4 The mass distribution of the product is: 27% C2H6; 33% C2H4; 13% H2; 27% CH4. 1. What was the conversion of C2H6 to CH4? 2. What was the yield of C2H4 expressed in kg of C2H4 ...

Analytical chemistry
Calculate the expected concentrations of vitamin B6 and caffeine in the stock solution assuming exactly 0.0506 g of pyridoxine hydrochloride (vitamin B6) and 0.1253 g of caffeine are dissolved in a 100 mL volumetric flask.

Chemistry
How would I make a 93.1% w/w solution from 96% sulfuric acid using volume

Chemistry
A 2.00L flask was filled with 4.00 mol of HI at a certain temperature and given sufficient time to react. At equilibrium the concentration of H2 was 0.400 M. Find the equilibrium concentrations of I2 and HI and then find the Keq at this temperature 2HI(g) <-> H2(g) + I2(g)

chemistry
normality of a solution containing 2g sodium carbonate in 250mL solution

chemistry
give the name of the process when anhydrous copper sulphate becomes wet

Chemistry
A 30.0 mL sample of 0.165 molL−1 propanoic acid (Ka=1.3×10−5) is titrated with 0.300 molL−1KOH. Calculate the pH at 0, 5,10, at equivalence point, 1/2 of the equivalence point, 20, 25 mL of added base.

chemistry
Changing 1 mol of Mg(s) and 1/2 mol of O2 (g) to gaseous atoms requires a total of approximately 150kJ of energy. The first and second ionization energies of Mg are 737kJ/mol and 1450kJ/mol respectively. The first and second electron affinities of Oxygen are -141KJ/mol and +...

Chemistry
Before small batteries were available, carbide lamps were used for bicycle lights. Acetylene gas, C2H2, and solid calcium hydroxide were formed by the reaction of calcium carbide, CaC2, with water. The ignition of the acetylene gas provided the light. Currently, the same lamps...

chemistry
State whether each of the following sets of quantum numbers is permissible for an electron in an atom. If a set is not permissible, explain why. (i) [1, 0, +1/2, +1/2] and (ii) [3, 2, 1, 1]

Chemistry
A student followed the procedure given in the lab exercise to determine the ascorbic acid content in a commercial vitamin C tablet. The students prepared the solution using a 0.460 g vitamin C tablet. The titration required 40.00 mL of the 0.005 M KIO3/KI solution to reach an ...

Chemistry
How many moles of air must be pumped into a 4.8 L tire to give it the pressure of 47.1 psi at 25°C ? I'm not sure how to even start doing this problem.

Chemistry
Is "a color of solution becoming less intense due to dilution" maybe evidence of chemical reaction or not?

Chemistry
Carbohydrates (such as C6H12O6) undergo combustion with oxygen to produce carbon dioxide and water. Living things use this reaction (a process called respiration) to produce energy. Determine the mass of carbohydrates consumed for every 0.300 mol of oxygen gas consumed during ...

Chemistry
8.8 g of iron(II) sulphide reacts completely with excess dilute hydrochloric acid. Calculate the volume of hydrogen sulphide evolved, measured at 18 º C and 729 mmHg pressure.

Chemistry
A sample of carbon monoxide was collected over water at a total pressure of 752 torr and a temperature of 15°C. What is the pressure (in torr) of the carbon monoxide?

Chemistry Lab
So I have a lab exam tomorrow and our instructor said that one of the questions would be as follows: Prepare 100mL of 0.03 M Copper Sulfate, beginning from copper sulfate pentahydrate. Calculate the exact molarity to 3 sig figs. Alright so I understand how to prepare 100mL of ...

Chemistry 20
a source of hydrogen is an important issue of hydrogen fuel cells are going to become useful in automobiles. What important perspective is missing?

Chemistry 20
If 4.56 mol of zinc react with excess copper (ii) sulphate, how many moles of precipitate will be formed?

chemistry
Explain why sodium carbonate against hydrochloric acid titration using phenophthalein titration do not go to completion but stop at the sodium hydrogen carbonate stage.

Chemistry
What is the morality of a solution prepared by dissolving 10.60g of sodium trioxocarbonate (v) in enough distilled water to obtain 250.0 ml of a solution?

Chemistry
1.654 of a hydrated acid H2C2O4.xH2O was dissolved in water and the soultion was made up to 250cm3 . 23.80cm3 of this solution required 25.00cm3 of 0.100moldm-3 NaOH to reach the end point. Identify the value of x and the formula of the hydrated acid H2C2O4.xH2Or.

Chemistry
To what pH should you adjust a standard hydrogen electrode to get an electrode potential of -0.122 V ? (Assume that the partial pressure of hydrogen gas remains at 1 atm.)

Chemistry
How much calories does it take to raise the temperature of 225 g of H2O from 25 °C to 100 °C. (Specific heat of water 4.182 J/(g* °C)

Chemistry
A patient requires 0.012 g of painkillers available as a 15 mg/ml solution. How many ml should be administered?

chemistry
What volume of alcohol would you use if you needed 25.0 g? Density is 0.7855 g/ml at 20°C

Chemistry
In an aqueous solution containing a mixture of Zn2+and Mg2+, how would you determine their contents by means of EDTA titration?

Chemistry
5g of salt are dissolved in 200g of water,what mass of solution is this?

Chemistry
Write a balanced overall reaction from these unbalanced half-reactions. Sn->Sn2+ Ag+->Ag Balanced overall equation I got Sn+2Ag+->Sn+2Ag, but its wrong.

chemistry
For the following reaction KClO2->KCl+O2 assign oxidation states to each element on each side of the equation. Reactants K=? Cl=? O=? Which element is reduced? I got K=5, Cl=-1, and O=-4 . The element that reduced is K, but its says its wrong. Help, Please!

Chemistry
A 24 L welding tank contains of 285 bar of argon at 28 °C. Nitrogen is added to obtain an 80:20 argon:nitrogen mixture. a) What are the partial pressures of argon and nitrogen? b) What will be the total tank pressure?

chemistry
Suggest a source of error (not already mentioned) that would result in a value of x that is a) higher than the actual value b) lower than the actual value

Chemistry 20
A student was experimentally checking the stoichiometry of a reaction. The student correctly predicted that the reaction should produce 1.82 g of al2(so4)3(s). When the student dried and weighed the al2(so4)3(s) produced, its mass was 1.94 g. The percent difference of the ...

Chemistry 20
When 1.2 x 10^-3 mol of nitric acid react with excess sodium carbonate, how many moles of carbonic acid are produced?

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