Wednesday
December 7, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry Solutions
Commercial Sodium hydroxide has a concentration of 19.4mol/L. How many milliliters of sodium hydroxide solution can be prepared from 59g or sodium hydroxide.
Saturday, November 5, 2016 by Isaac

chemistry
The amount of lead in drinking water is 0.025 mg/L. Express this concentration in molality. {molar mass of lead is 207.2 g/mol and the density of water is 1.00 g/cm.}
Saturday, November 5, 2016 by karen

chemistry
Identify which of the following function are Eigen functions of the operators d/dx and give the corresponding Eigen value (1). ¥= e^ikx (2). ¥= coskx (3). kx
Saturday, November 5, 2016 by Aweda

chemistry
The speed of a certain proton is 4.5×10^5m/s. If the uncertainty in its momentum is to be reduced to 0.1%. Calculate the uncertainty in its position
Saturday, November 5, 2016 by Aweda

chemistry
Calculate the linear momentum of photon of wavelength 750nm. What speed does an electron need to travel to have the same linear momentum.
Saturday, November 5, 2016 by Aweda

chemistry
Calculate the Debroglie wavelength of a mass 1.0g traveling at 1.0cm/sec
Saturday, November 5, 2016 by Aweda

Chemistry
A compressed air tank carried by scuba divers has a volume of 9.5 L and a pressure of 140 atm at 20?C. If the gas was instead in a cylinder with a floating, massless, frictionless piston, what would the volume of the gas be (in liters) at STP? Express the volume in liters to ...
Saturday, November 5, 2016 by Jessica

Chemistry
To treat a burn on your hand, you decide to place an ice cube on the burned skin. The mass of the ice cube is 18.5 g, and its initial temperature is -13.3 °C. The water resulting from the melted ice reaches the temperature of your skin, 28.4 °C. How much heat is ...
Friday, November 4, 2016 by Annie

chemistry
A sample of 45.1 g of methane gas (CH4(g)) has a volume of 6.20 L at a pressure of 2.90 atm. Calculate the temperature. Another one that I'm stumped on, last question for my practice exam, can you explain how to solve?
Friday, November 4, 2016 by Jordan

chemistry
When the following solutions are mixed together, what precipitate (if any) will forms? Write the reaction equation for all the cases and write the net ionic equation for only those reactions that react: potassium nitrate solution and barium acetate I am seriously lost on this...
Friday, November 4, 2016 by Jordan

Chemistry 101
Which calorimeter do you use for determining the specific heat of the metal, the thermos or the Styrofoam cup?
Friday, November 4, 2016 by Dina

Chemistry
How much energy in joules does it take to raise the temperature of 255g of water by 12.5 C? I just don't know which formula to use. Every formula I look at has 3 components needed, but I'm only given 2. Thanks :)
Friday, November 4, 2016 by Aiyanna

chemistry
Molarity material = density x 1000 x (%/100) x (1/molar mass material) 1000 indicates?
Friday, November 4, 2016 by karen

chemistry
Write a balanced equation for the double-replacement precipitation reaction described, using the smallest possible integer coefficients. A precipitate forms when aqueous solutions of iron(II) iodide and sodium hydroxide are combined.
Friday, November 4, 2016 by Erika

Chemistry
N2(g) + 3H2(g) -> 2NH3(g) How many grams of ammonia are formed from 14.0 grams of nitrogen? 14/2 = 7 grams of ammonia
Friday, November 4, 2016 by Anonymous

chemistry
For the equilibrium: H2 + I2 <=> 2HI The equilibrium konstant Kc is equal to 50.5 at 448ºC. If [H2]o=[I2] o= 1 mol/l. What will the concentration of H2, I2 and HI be at equilibrium
Friday, November 4, 2016 by vicky

chemistry
Which neutral atoms have the following electron configurations in either a ground state or excited state? Enter the name or symbol. [Ar]4s23d3 - I know that this is Vanadium [Xe]6s24f1 - I thought that this was Lu but it counts it wrong each time! Help please!
Friday, November 4, 2016 by Jordan

chemistry
Quantum numbers arise naturally from the mathematics used to describe the possible states of an electron in an atom. The four quantum numbers, the principal quantum number (n), the angular momentum quantum number (?), the magnetic quantum number (m?), and the spin quantum ...
Friday, November 4, 2016 by Jordan

chemistry
How many milliliters of concentrated nitric acid, HNO3, 70 % (wt/wt) are required to prepare 1 liter of 0.250 M solution? The molar mass and density of HNO3 are 63.0 g/mol and 1.36 g/cm respectively.
Friday, November 4, 2016 by karen

chemistry
10 litres of a monoatomic ideal gas at 0degree celsius and 10atm pressure is suddenly released to 1atm and the gas expands adiabatically against this constant pressure. find the final temperature and volume
Friday, November 4, 2016 by dhwani

chemistry
Why is it necessary to heat the hydrate gently at first and then more strongly only after most of the water has been driven off?
Friday, November 4, 2016 by Missy

chemistry
A 0.940g sample of barium chloride dehydrate is heated and 0.800g of anhydrous residue remains after cooling. A. How many moles of anhydrous barium chloride were present in the sample? B. How many moles of water were present in the sample?
Friday, November 4, 2016 by Aima

Chemistry
Methane and diamond have covalent bonds.Explain why methane is a gas and diamond is a solid at room temperature.
Friday, November 4, 2016 by Maureen

Chemistry
At high concentrations of [H2] the observed rate law is found to change to the form: Rate = k[NO]^2 i.e. the rate becomes independent of [H2]. 1. Assess whether the two step mechanism: H2 + 2NO ? N2 + H2O + O (k1) O + H2 ? H2O (k2) can explain this additional data. Reexamine ...
Friday, November 4, 2016 by Susie

chemistry
equilibrium is reached when red hot iron reacts with steam.why?
Thursday, November 3, 2016 by priyanshi

Chemistry
Calculate the amount of hydrogen gas and zinc sulphate produced when 40gram of zinc reacts with sulphuric acid
Thursday, November 3, 2016 by Mahi agarwal

Chemistry
A cold pack manufacturer has decided to change the chemical in their cold pack from ammonium nitrate to ammonium chloride, a safer chemical. The original cold pack formulation used 100.0g of room temperature (27.0C) water and 35 g of ammonium nitrate. Assume that the solution ...
Thursday, November 3, 2016 by Bob

Chemistry
Products of elimination reactions are?: a) unsaturated b) electrophilic c)More hydrophilic than their reactants d)Heavier than the reactions If you could also explain why, that would be great :)
Wednesday, November 2, 2016 by arthur

chemistry
A mixture of NaOH and HCl is formed in a calorimeter. There is 50 mL of 2.078 Molar HCl and 51.7mL of 2.134 Molar NaOH. How would the heat capacity of the calorimeter change if you were to double the volume of NaOH? Justify your answer
Wednesday, November 2, 2016 by Max

Chemistry
Elements A and B combine to form two different compounds. The first compound contains 15.0 grams of substance A, and 8.60 grams of substance B. It can be represented by the formula A2B (subscript 2). The second compound contains 5.0 grams of substance A, and 4.30 grams of ...
Wednesday, November 2, 2016 by N

chemistry
A student conducts a reaction and measures a 19.9 g yield. The theoretical yield of the reaction under the conditions used is 31.4 grams. What percent yield did the student achieve?
Wednesday, November 2, 2016 by Alyssa

Chemistry
The iodine-131 nuclide has a half-life of 8 days. If you originally have 625-g sample, how many grams will you have after 2 months(approximately 64 days)?
Wednesday, November 2, 2016 by Please help

Chemistry
The cesium-131 nuclide has a half life of 30 years. After 90 years, about 6g remain. What is the original mass of the cesium-131 sample?
Wednesday, November 2, 2016 by Please help

Chemistry
Technetium-99 has been used as a radio graphic agent in bone scans. If the isotope has a half life of 6.0 hours, what amount is left of 10.0 mg after 2 days?
Wednesday, November 2, 2016 by Please help

Chemistry
If the half life of Pu-239 is 2.4 x 10^4 years, how many years are required for a 20-gram sample of plutonium-239 to be reduced to a mass of 5 grams?
Wednesday, November 2, 2016 by Please help

Chemistry
A particular radioactive element has a half life of 10.0 days. How much is left after 30.0 days if the sample started with 345g?
Wednesday, November 2, 2016 by Please help

chemistry
A solution contains 0.100 mg of NaOH dissolved in enough water to make 10.0 L of solution. whats the concentration
Wednesday, November 2, 2016 by byu

Chemistry
What mass, in grams, of sodium chloride is needed to prepare 15.0 ml of 10% (m/v) NaCl solution?
Wednesday, November 2, 2016 by Irene

Chemistry
At a certain temperature, 0.885 mol of N2, and 2.654 mol of H2 are placed in a container. N2+3H2=2NH3 At equilibrium, there is 0.823 mol of NH3 present. Determine the number of mol of N2 and H2 that are present when the reaction is at equilibrium. Answer in moled of N2 at ...
Wednesday, November 2, 2016 by Ashley

Chemistry 1
Calculate q when 22.0 g of water is heated from 25.0°C to 100.0°C.
Wednesday, November 2, 2016 by Someone

Chemistry
How much heat is required to convert solid ice with a mass of 810 g and at a temperature of -18.0 °C to liquid water at a temperature of 62.5 °C? (The specific heat of ice is cice = 2100 J/kgK, the specific heat of water is cwater = 4186.8 J/kgK, and the heat of fusion...
Wednesday, November 2, 2016 by Anonymous

Chemistry
A calcium sample weighting 607.4 mg was precipitated as oxalate and calcined calcium carbonate giving 246.7 mg. What the percentage of calcium in the sample? Calcium molecular weight: 40.078 g/mol CaCO3 molecular weight: 100 g/mol
Wednesday, November 2, 2016 by MONICA

Chemistry
100 g piece of granite and a 100 g piece of lead are placed in an oven that is at 100°C. The initial temperature of the pieces are 25°C. After a couple of minutes, neither one is at 100°C, but which one is warmer? Which one will reach 100°C first? How much ...
Wednesday, November 2, 2016 by Someone

chemistry
Calculate the number of moles of O2 that can be produced by the decomposition reaction of water
Wednesday, November 2, 2016 by gjf

Chemistry
What amount of naoh require to neutralize 1kg HCl
Wednesday, November 2, 2016 by Pravin

chemistry
C4H10(g) + 13/2 O2> 4CO2(g)+ 5H2O(g) Hrxn -2658Kj What mass of butane in gms is necessary to produce 1.5 times ten ^3Kj of heat? What mass of CO2 is produced?
Wednesday, November 2, 2016 by gladstone

Chemistry
Half life period of Ra226 is 1620 years calculate the decay rate of Ra226 in alpha particle per gram per sec
Wednesday, November 2, 2016 by Shilva

chemistry
0.049M solution of NaOH was used to standerize a solution of HCl. 20 ml of aliquot of sodium carbonate was placed was placed in a conical flask and titrated with HCl from a buret . the correct indicator for this reaction would be one of the changes colour when the number of ...
Wednesday, November 2, 2016 by raja

Chemistry
When a 3.80 g sample of magnesium nitride (MW 101g/mol) is reacted with 3.30 g of water, 3.60 g of MgO is formed. What is the percent yield of this reaction? Mg3N2 + 3 H2O --> 2 NH3 + 3 MgO
Wednesday, November 2, 2016 by Jessica

Chemistry
...Zn(s) + ...H+(aq)--> When the equation for the reaction represented above is completed and balanced and all coefficients are reduced to lowest whole number terms, the coefficient for H+ is? Am I just supposed to know what products are made from this redox? Say I don'...
Wednesday, November 2, 2016 by Wenny

Chemistry
Consider the reaction between 56.0 mL of liquid ethanol (C2H5OH; density = 0.789 g/mL) and 26.0 L of O2 at 27.0°C and a pressure of 1.95 atm. The products of the reaction are CO2(g) and H2O(g). Calculate the number of moles of H2O formed if the reaction goes to completion.
Tuesday, November 1, 2016 by Anonymous

Chemistry
What is the frequency of light that is composed of photons that each has an energy of 5.20 × 10?25 J -Do I divide this by 3.00 X 10^8
Tuesday, November 1, 2016 by Rebbeca

Chemistry
net ionic equation of 3Cr(c2h3o2)2 +2(nh4)3(po4)--Cr3(po4)2+6Nh4(c2h3o2)wit​h states
Tuesday, November 1, 2016 by Kendall De

chemistry
If our eyes could see a slightly wider region of the electromagnetic spectrum, we would see a fifth line in the Balmer series emission spectrum. Calculate the wavelength ? associated with the fifth line. Express your answer with the appropriate units.
Tuesday, November 1, 2016 by myah

Chemistry (Concentratrion/molarity)
A 25.00 mL aliquot of HCl of unknown concentration is titrated with 25.62 mL of 0.1011 M NaOH. What is the molarity of the HCl solution?
Tuesday, November 1, 2016 by Ray

college chemistry
Stomach acid is composed primarily of HCl. If the concentration of the acid is 0.010M and it has a volume of 75 mL, how many generic tablets would you need to fully neutralize the acid? (Use your data) I just don't know where to start for this question, or the steps to ...
Tuesday, November 1, 2016 by jamie

AP Chemistry Help!
I had to conduct an experiment to find the enthalpy of reaction for : 4Fe + 3O2 + 6H2O ----> 4Fe(OH)3 In the experiment , I started with an inital temperature of 22.3 C and edned with 36.7 C so the delta T is +14.4C. Now it's telling me to calcualte the delta Hrxn for ...
Tuesday, November 1, 2016 by Jessica

Chemistry
I need help writing the net ionic equation for 3Cr(c2h3o2)2 +2(nh4)3(po4)--Cr3(po4)2+6Nh4(c2h3o2)wit​h states
Tuesday, November 1, 2016 by Kendall De

Chemistry
Stomach acid is composed primarily of HCl. If the concentration of the acid is 0.010M and it has a volume of 70 mL, how many generic tablets would you need to fully neutralize the acid? (Use your data) I just don't know where to start for this question, or the steps to ...
Tuesday, November 1, 2016 by jamie

Chemistry
What is the balanced equation for the reaction including states? Does it form a precipitate? Cu(NO3)2 + KI
Tuesday, November 1, 2016 by Kendall De

Chemistry
complete and balance NaHCO3 (aq) + H2SO4 (aq)
Tuesday, November 1, 2016 by Angele

Chemistry
Formula of (ch3ch2)2chch2ch(ch3)2
Tuesday, November 1, 2016 by Anonymous

Chemistry help emergency? (theoretical mass/mol)
I am supposed to calculate the theoretical mass and moles of Cu. However I am given the mass of 2 reactants in the balanced equation: 3CuCl2*2H2O + 2Al -> 3Cu + 2AlCl3 + 6H2O I am given the mass of CuCl2*2H2O to be 0.477g and the mass of Al is 0.267g. If I wanted to ...
Tuesday, November 1, 2016 by ray

Chemistry 11
A 5.0 g sample of Cu(NO3)2-nH20 is heated, and 3.9 g of the anhydrous salt remains. What is the value of n? I got as far as finding the molar mass of Cu(NO3)2, which is 187.5g/mol Please help me further with this question.
Tuesday, November 1, 2016 by Rona

chemistry
Copper used in electric wires comes in two flavors (isotopes): 63Cu and 65Cu. 63Cu has an atomic mass of 62.9298 amu and an abundance of 69.09%. The other isotope, 65Cu, has an abundance of 30.91%. The average atomic mass between these two isotopes is 63.546 amu. Calculate the...
Monday, October 31, 2016 by andrea

physical chemistry
The ice skate of a 210-pound hockey player is in contact with the ice over a 2.5mm x 15cm area. Determine the freezing point of the ice under the blade of the skate?
Monday, October 31, 2016 by Joseph

Organic Chemistry
Draw the product of the reaction: CH3CH2CH (double bond) CH2 + Cl2
Monday, October 31, 2016 by Dominique

chemistry
what is the name of this coordination compound [CoSO4(NH3)5]Br?
Monday, October 31, 2016 by James

chemistry
If I only have the name of this transitional coordination compound, bis(enthylenediamine)dinitroiron (III) sulphate how do you find the 2 outside the square bracket of this same thing but in formula form? [Fe (en)2 (NO2)2]2SO4 thanks.
Monday, October 31, 2016 by Sherlique

chemistry (charges)
just want to check if this group is neutral, R-NH2 thanks!
Monday, October 31, 2016 by Anonymous

chemistry
HClO4 Express your answers as ions separated by a comma.
Monday, October 31, 2016 by Precious Wiefue

physical chemistry
Calculate the freezing point of water at a depth of 10.0 cm below the surface of the water. The density of the water is 0.9998 g/cm3
Monday, October 31, 2016 by Joesph

Chemistry
Calcium oxide, or lime, is produced by the thermal decomposition of limestone in the reaction CaCO3(s) arrow CaO(s) + CO2(g). What mass of lime can be produced from 2001.2 kg of limestone?
Monday, October 31, 2016 by Andrew

Chemistry
For the reaction HCl + NaOH → NaCl + H2O, how many moles of hydrochloric acid are required to produce 281.0 g of water?
Monday, October 31, 2016 by Andrew

Chemistry
how many milliliters of concentrated H2SO4 of density 1.84 containing 95.6% by weight of the acid is required to prepare 5litres of battery acid of density 1.18 containing 25.2% by weight of acid?
Monday, October 31, 2016 by Evarestus

Chemistry
The combustion of a hydrocarbon X (30 cm3) with 350 cm3 of oxygen at STP resulted in the formation of 440 cm3 of gaseous products. The volume of gases was reduced to 360 cm3 when the excess O2 was removed and then reduced by half when bubbled through NaOH.
Monday, October 31, 2016 by Cavenia

science, organic chemistry
Determine the amount of compound remaining in the aqueous phase and organic phase and organic phase if a 5.0g organic compound is dissolved in 100 mL of water and is extracted with three 50-mL portion of ether (kb= 10). Compare this with one 150 ml portion with ether. Which is...
Monday, October 31, 2016 by Anonymous

Chemistry
Consider an ionic compound, MX2, composed of generic metal M and generic, gaseous halogen X. The enthalpy of formation of MX2 is ΔHf° = –799 kJ/mol. The enthalpy of sublimation of M is ΔHsub = 157 kJ/mol. The first and second ionization energies of M are IE1...
Monday, October 31, 2016 by Joseph

Chemistry
How can I draw a lewis dot structure of XeF2O?
Sunday, October 30, 2016 by Joseoh

chemistry
what is the name of this coordination compound [CoSO4(NH3)5]Br? my attempt: cobaltsulfatepentaamine Bromine
Sunday, October 30, 2016 by chemi

Chemistry
Consider an ionic compound, MX2, composed of generic metal M and generic, gaseous halogen X. The enthalpy of formation of MX2 is ΔHf° = –799 kJ/mol. The enthalpy of sublimation of M is ΔHsub = 157 kJ/mol. The first and second ionization energies of M are IE1...
Sunday, October 30, 2016 by Joseoh

chemistry
Oxygen gas and aqueous benzoic acid react to form carbon dioxide gas and water gas. Determine the mass of water in grams if 5.43×104 milligrams of oxygen reacts with an excess of benzoic acid. I balanced the equation to 2C7H6O2+15O2=14CO2+6H2O
Sunday, October 30, 2016 by paige

Chemistry
Which one of the following is NOT a physical process? A. Dry ice subliming B. Steam condensing C. Alcohol evaporating D. Melting ice E. Gold plating jewelry
Sunday, October 30, 2016 by Anjali

Chemistry
Consider the following reaction. 2Fe2O3 --> 4Fe+3O2 Hrxn=+824.2 The Formation of 21.0 of Fe results in 1)the release of 77.5 kJ of heat. 2)the absorption of 3.10 × 102 kJ of heat. 3)the release of 4330 kJ of heat. 4)the absorption of 77.5 kJ of heat. 5)the release of ...
Sunday, October 30, 2016 by Danny

chemistry
The ice skate of a 210-pound hockey player is in contact with the ice over a 2.5mm x 15cm area. Determine the freezing point of the ice under the blade of the skate?
Sunday, October 30, 2016 by Joseph

chemistry
Calculate the work done (in joules) when 5.0 mole of water is frozen at 0°C and 1.0 atm. The volumes of five moles of water and ice at 0°C are 0.0900 L and 0.0980 L, respectively.
Sunday, October 30, 2016 by Dani

chemistry
Calculate the heat of decomposition for this process at constant pressure and 25°C. (Look up the standard enthalpy of formation of the reactant and products in the table; ΔH°f(BaCO3(s)) = -1218.8 kJ/mol, ΔH°f (BaO(s)) = -558.2 kJ/mol and ΔH°f (...
Sunday, October 30, 2016 by Dani

chemistry
Calculate the heats of combustion for the following reactions from the standard enthalpies of formation listed in Appendix 2. (ΔH°f (HgO(s)) = -90.7 kJ/mol and ΔH°f (FeO(s)) = -272 kJ/mol.) (a) 2 Fe(s) + O2(g) 2 FeO(s) kJ (b) 2 CH3OH(l) + 3 O2(g) 2 CO2(g) + 4...
Sunday, October 30, 2016 by Dani

chemistry
Ethanol (C2H5OH) and gasoline (assumed to be all octane, C8H18) are both used as automobile fuel. If gasoline is selling for $1.45/gal, what would the price of ethanol have to be in order to provide the same amount of heat per dollar? The density and ΔH°f of octane ...
Sunday, October 30, 2016 by Dani

Chemistry
A 2.35 g sample of a substance suspected of being pure gold is warmed to 72.2 ∘C and submerged into 15.5 g of water initially at 24.1 ∘C. The final temperature of the mixture is 26.5 ∘C. Part A What is the heat capacity of the unknown substance? Part B Could ...
Sunday, October 30, 2016 by Jo n

Chemistry
Suppose a student diluted and titrated a bleach unknown exactly as described in the experimental procedure, except only a single titration was performed which required 12.62 mL of 0.100 M Na_{2}S_{2}O_{3} Calculate the number of moles of ClO in the sample titrated.
Sunday, October 30, 2016 by Linda

Chemistry
how many grams of pure uranium can theoretically be extracted from 10.0kg sample of pitchblende which is 92.0%uo2
Sunday, October 30, 2016 by Tamo

Chemistry
What ionic compound, is the primary source of a chicken's egg? I think it is calcium carbonate? If it is thought what is the logical/ explanation behind it can someone please explain this to me. Btw what would be the chemical equations for an egg being placed in water, and...
Sunday, October 30, 2016 by Holfbrincl PLEASE HELP

Chemistry
Does group 18 elements like He, Ne, Ar, Kr soluble in organic solvents?
Sunday, October 30, 2016 by Husler

chemistry
Calculate the freezing point of water at a depth of 10.0 cm below the surface of the water. The density of the water is 0.9998 g/cm3.
Sunday, October 30, 2016 by Joseph

chemistry
When performing an extraction, is it better to have a higher or lower K (distribution coeffictient/ partition coefficient) value? Explain.
Sunday, October 30, 2016 by Chem

Chemistry-Dr.Bob
The specific rotation of pure enantiomer is known from the literature to be -20. The measured value of a solution containing A plus its enantiomer B (specific rotation must be +20) is -40. What is the ee (enantiomer excess) of this sample?
Saturday, October 29, 2016 by Sarah

Chemistry
The specific rotation of pure enantiomer is known from the literature to be -20. The measured value of a solution containing A plus its enantiomer B (specific rotation must be +20) is -40. What is the ee (enantiomer excess) of this sample?
Saturday, October 29, 2016 by Sarah

Chemistry
To what volume must 10ml of 5M HCl be diluted to make a 0.5M HCl solution......???? A.1ml B.50ml C.100ml D.500ml E.1000ml
Saturday, October 29, 2016 by Sawera

Chemistry
Does group 18 elements soluble in organic solvents such as tetra-chloro-methane or alcohol
Saturday, October 29, 2016 by Husler

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Homework Help: Science