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February 23, 2017

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Define the law of the conservation of mass. Using this definition: if you have the reaction of 40 g of water decomposing into hydrogen and oxygen what would be the total mass of your products?
Tuesday, November 8, 2016 by Please help

chemistry
How would you prepare 1. 100 ml of 0.20 M Ca(OH)2 from 0.50 M Ca(OH)2
Tuesday, November 8, 2016 by casey

chemistry
Nitrogen gas can be prepared by passing gaseous ammonia over solid copper (II) oxide at high temperature. The other products of the reaction are solid copper and water vapor. If a sample containing 20.3 g of NH3 is reacted with 95.8 g of copper oxide 1. Which is the liming ...
Tuesday, November 8, 2016 by casey

Chemistry
what kind of reaction is this Sr(NO3)2 (aq) + K2CrO4 (aq) = SrCrO4 (S) + 2KNO3 (aq) and does it take place or NR, why?
Tuesday, November 8, 2016 by ina

Chemistry
80.0 ml of 1.50 M lead (IV) acetate is added to a 65.5 ml solution of 1.25 potassium chloride. 5.84 grams precipitate are collected. what is the percent yield? Calculate the concentrations of all ions remaining in solution. Okay so I know you have to convert to moles of each ...
Monday, November 7, 2016 by Kenzie

Chemistry
How do you create a calibration curve? How do you use a calibration curve to convert absorbance to concentration in mg/mL?
Monday, November 7, 2016 by Sal

chemistry
P4 + 6 Br2 -> 4PBr3 In a particular reaction, 20 grams of phosphorus P4, is combined with 50mL liquid bromine ( Density= 2.93 g/ml) 1) Calculate the mass of product in grams for each of the reactants 2) Limiting reagant and Mass Maximum mass of PBr3 so for 1) I converted ...
Monday, November 7, 2016 by jake

Chemistry
Please Help me!! NaCl(aq)+Hg2(C2H3O2)2(aq)→ Express your answer as a chemical equation. Enter noreaction if no precipitate is formed
Monday, November 7, 2016 by Liselle

chemistry
A 9.35 gram of ring with it's volume of 0.654 cm3 is an alloy of gold and with density of gold and silver respectively 19.3 g/cm3 and 10.5 g/cm3 assume there is no change in volume when pure metals are mixed. calculate volume of gold?
Monday, November 7, 2016 by Anonymous

chemistry
A 9.35 gram of ring with it's volume of 0.654 cm3 is an alloy of gold and with density of gold and silver respectively 19.3 g/cm3 and 10.5 g/cm3 assume there is no change in volume when pure metals are mixed. The volume of gold is?
Monday, November 7, 2016 by sami

Chemistry
Can you check my answers? Thanks!!!! What would happen to the volume-to-temperature ratio if: 1. One student failed to replenish the boiling water in the boiling-water bath as the flask was being heated. At the end of the 6 min of heating, the boiling water in the bath was ...
Monday, November 7, 2016 by Steve

chemistry
Calculate the volume of HNO3 that must be introduced in the calorimeter,knowing that it were used 60 ml NaOH, Cc=100cal/grd and delta H=-13,5 kcal/mol.. please help me,i have no clue for this..
Monday, November 7, 2016 by Alberto

Chemistry
Calculate enthalpy of reaction C2H4 + H2 gives C2H6.enthalpy of combustion of ethene, H2,and ethane are -1410,-286,-15.60kj/mol respectively
Monday, November 7, 2016 by Shaika

chemistry-buffer
if you added 4ml NaOH 1M to your 100ml 0.1M buffer, would it still be a usable buffer according to our convention? Explain why or why not(math would be good at here)
Monday, November 7, 2016 by yy

Science
Consider the diatomic molecule Na2. For simplicity let the basis set consist of the orbitals: and . In the molecule the overlap integral between the 3s orbitals is 0.45. Answer the following questions using the orbital energies determined using the Revised Slater’s Rules ...
Sunday, November 6, 2016 by Soso

Chemistry
What diff will appear in the mass no.if the no. of neutron is halved no. of electron is doubled in 8 O 16
Sunday, November 6, 2016 by Ayushi

Chemistry
What mass of carbon dioxide is formed by the complete combustion of 760 g of ethanol?
Sunday, November 6, 2016 by Jay

Chemistry
Solubility of PbCl2 in brine solutions
Sunday, November 6, 2016 by Armando

Chemistry
You have isolated compound X from panda pancreas. You started with a whole pancreas, and finished up with 5 ml of a pure solution of X. Assume you got 100% recovery of compound X. You take 300 µl of this solution, and add it to 1.7 ml of buffer. The absorbance of this dilute ...
Sunday, November 6, 2016 by Student

Chemistry
sodium carbonate + hydrochloric acid --> sodium chloride + carbonic acid which later decomposes into water + carbon dioxide. Which one would be the independent, controlled, dependent variable? i know independent would have to be from the reactant side and dependent from the...
Sunday, November 6, 2016 by Holfbrincl

chemistry
arrangement of the following gas molecule in their increasing average speed at the same temperature. O2, N2, H2O,CO2,NO2 and Cl2
Sunday, November 6, 2016 by michael

chemistry
The atomic mass of an element is 27.and its equivalent mass is 9.the vapour density of chloride is
Sunday, November 6, 2016 by Anonymous

chemistry
1.Name the type of solution 45g of NaCl in 100g of water at 80 degree celcius. 2. 39g of NaCl in 100g of water at 80 degree celcius
Sunday, November 6, 2016 by karthik

Chemistry
if 4.307 grams of water is decomposed by an electrical current how much oxygen gas will be produced?
Saturday, November 5, 2016 by Rae

Chemistry
if 7.653 grams of water is decomposed by an electrical current how much oxygen gas will be produced?
Saturday, November 5, 2016 by Rae

Chemistry
In a similar experiment, a sample of tin metal was dissolved in nitric acid to produce 23.00 mL of solution containing Sn2+. Titration analysis resulted in the calculation that the concentration of Sn2+ in this solution was 0.65 mol/L. b. What mass of tin was used to make the ...
Saturday, November 5, 2016 by james

chemistry
calculate the number of moles of cacl2 that can be obtained from 25g of limestone caco3 in the prescence of excess hydrogen chloride
Saturday, November 5, 2016 by esther

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 absorbed by ...
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 (ℓ), the magnetic quantum number (mℓ), 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. ...
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 for ...
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 energy will it ...
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't ...
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 λ 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 answer...
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 the ...
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 answer ...
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

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Homework Help: Science