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December 6, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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...
Thursday, June 23, 2016 by Anonymous

Chemistry
A 1.00 L flask is filled with Ar by water displacement at 20.0°C. the atmospheric pressure is 759.6 torr. after correcting for water vapor pressure in the flask, determine how many moles of Ar are present
Wednesday, June 22, 2016 by lol no

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...
Wednesday, June 22, 2016 by Susie

Chemistry
3 Cl2 + 6 KOH go to KClO3 + 5 KCl + 3 H2O how many moles of KClO3 form when 2 grams of KOH react completely
Wednesday, June 22, 2016 by Samantha

Chemistry
The amount of energy released by the combustiom of 100 g of C2H2 (g) is ______ MJ. 2CH2 + 5O2 ----> 4CO2(g) + 2H2O(g) ΔH= -2511.0 kJ Do I use ΔH = Hproducts - Hreactants? And if so how would that help me solve for the energy released?
Wednesday, June 22, 2016 by Anonymous

Chemistry
For the reaction: Pb(NO3)2(aq) + 2KCl(aq)->PbCl2(s) + 2KNO3(aq) How many grams of PbCl2 will be formed from 63.0 mL of a 1.60 M KCl solution?
Wednesday, June 22, 2016 by Terri

chemistry
Write the condensed structural formulas for the following alcohols."" Correct the incorrect names."" 4-methyl-1-pentanol 2-methyl-2-butanol 3-ethyl-1-butanol 2, 2-diethyl-4-pentanol 3-ethyl -2-hexanol IS THERE ANY WRONG NAMES??
Wednesday, June 22, 2016 by angy

Chemistry
How many grams of NH3 is there in 800 cm^3 at STP of NH3 gas?
Wednesday, June 22, 2016 by Shipra

chemistry
The amount of energy required to remove an electron from the surface of Hg is 7.22x10^-19 J. What is the threshold frequency of mercury? I got 1.09*10^15 hz is it right?
Tuesday, June 21, 2016 by lo

Chemistry
Given that W = -PatmΔV, if a gas expands into a vacuum, the sign of W is ? 1. Positive: work is being done on the gas 2. Negative: work is being done on the gas 3. Positive: work is being done by the gas 4. Negative: work is being done by the gas 5. ZERO: no work is being...
Tuesday, June 21, 2016 by Melodie

Chemistry
The experimentally determined rate law for the reaction H2 + NO --> ½N2 + H2O is Rate = k[H2][NO]2. Is the mechanism below possible? Step 1: H2 + NO --> N + H2O Slow Step 2: N + NO -->N2 + O Fast Step 3: O + H2 --> H2O Fast 1. Yes...
Tuesday, June 21, 2016 by Hs

Chemistry
Is NH4+ polar or non polar?
Tuesday, June 21, 2016 by sarah

chemistry
Is NH4+ po;ar or non polar?
Tuesday, June 21, 2016 by sarah

Chemistry
Calculate the mass of HF required to prepare 200 mL of 0.25 mol/L solution. P = 40%; d = 1.14 g/cm3
Tuesday, June 21, 2016 by Jacke

Chemistry
I have the answer to this question but the book does not explain WHY this is a good buffer solution? It uses pH=pKa - log(base/acid) and shows 7.2=7.2 - log(1). I don't understand why they can only use pKa7.2 and ignore the pKa 12.7. You are instructed to prepare 100ml of ...
Tuesday, June 21, 2016 by Kelsey

Chemistry
Consider a cylinder containing 2 mol of an ideal gas at an initial temperature of 25 C. The cylinder is fitted with a piston on which a weight is placed, subjecting the gas to a constant pressure of 2.66 atm. The cylidner is then wrapped with a heater, from which 1.50 kJ of ...
Tuesday, June 21, 2016 by Chris Tesler

Chemistry
A 53.8-mg sample of sodium perchlorate contains radioactive chlorine-36 (whose atomic mass is 36.0 amu). If 29.6% of the chlorine atoms in the sample are chlorine-36 and the remainder are naturally occurring nonradioactive chlorine atoms, how many disintegrations per second ...
Tuesday, June 21, 2016 by Harry

Chemistry
Rule of thumb gives the activation energy of most organic reactions as approximately 50 kJ/mol. Based on that, calculate by what factor the reaction rate increases when the temperature climbs from 25°C to 45°C. 1. 3.6 2. 3.2 x 1046 3. 1.001 4. 1.3
Tuesday, June 21, 2016 by TS

Chemistry
will red blood cells undergo hemolysis, crenation or no change at all. 10%m/v NaCl 2% m/v glucose H2O 5% m/v glucose how would I come up with the answer I read the chapter and i'm confused
Tuesday, June 21, 2016 by Jason

chemistry
Why reversible reaction never complete
Tuesday, June 21, 2016 by ali

chemistry
What is pOH of 0.1M H2SO4?
Monday, June 20, 2016 by padamraj

chemistry
Ba(OH)2(aq) + HCl(aq) BaCl2(aq) + H2O (g) Consider the unbalanced equation above. What is the concentration of the original hydrochloric acid solution if 18.0 mL of the acid reacts with 45.5 mL of 0.280 M barium hydroxide?
Monday, June 20, 2016 by zack

Chemistry
Describe the ammonium ion, NH4+, and the sulfate ion, SO42-. What compounds would these ions form with potassium and fluoride ions? Write the formula units for the resulting compounds.
Monday, June 20, 2016 by Adimi

Chemistry
How many liters of 0.85 M HCl solution would react completely with 3.5 moles Ca(OH)2?
Monday, June 20, 2016 by Kevin

Chemistry
The Ka of an acid is 1.3 x 10–7. Based on the Ka and its relationship with Kw, what is the value of Kb?
Monday, June 20, 2016 by Kelly

Science chemistry
Which compound has the melting point of -23 degree Celsius and boiling point of 77 degree Celsius ? Thx....
Monday, June 20, 2016 by Tan

chemistry
a hydrocarbon was burnt completely and the products were bubbled into excess of Ca(OH)2 solution. The resulting mixture was filtered, and the residue dried and weighed. The mass of the hydrocarbon was found to be 10.00g. In a separate experiment, the same amount of hydrocarbon...
Sunday, June 19, 2016 by kandace

Chemistry
A solution is made by dissolving 32g KCIO3 in 100g H20 at 80C. The solution is cooled to 10C. Describe what you would observe as it cooled and state what temperature this first occurs at. What mass of crystals would settle out of the solution?
Saturday, June 18, 2016 by Naomi

chemistry
4gm of NaOH can be neutralised by? 1) 100ml of 1N HCl 2) 200ml of N/2 H2SO4 3) 1000ml of N/10 KOH 4) 2000 ml of M/20 H3PO4
Saturday, June 18, 2016 by Mukul

Chemistry
Write the equation for the reaction of iron and oxygen. Label the oxidizing reagent, the reducing agent, the reduced element, and the oxidized element.
Friday, June 17, 2016 by Tammy

Chemistry
in the reactionN2+3h2=2nh3 42.02 g of n2 is consumed of all gases are at satp the number of moles of nh3 produced is
Friday, June 17, 2016 by koko

chemistry
calculate the momentum of a particle ,whose de Broglie's wave length is 0.1nm ?
Friday, June 17, 2016 by nitin

chemistry
what is the mole of a solution that has 6 mole of Ca-Cl 2 in 3 kg of water?
Thursday, June 16, 2016 by Anonymous

Chemistry
When the pressure exerted on 1.0L of an ideal gas is quadrupled, and the kelvin temperature is tripled,what does the volume become?
Thursday, June 16, 2016 by Kyla

Chemistry
How to determine SiO2/Na2O ratio after mixing Na2SiO3 (SiO2=30%, Na2O=9%, water=61%)and NaOH (8M)solutions?
Thursday, June 16, 2016 by MJ

chemistry
You have a solution that contains 0.25g grams of oxalic acid dissolved in 100 mL of water. This solution is placed in a separating funnel, and the 100 mL of butanol is added to the solution. calculate the mass of oxalic acid in the organic solvent
Thursday, June 16, 2016 by Grace

Organic chemistry
What are the examples of compounds extracted by solvent diethyl ether?
Thursday, June 16, 2016 by Ummi Hani

Chemistry
How many ml of 8.00 M Na OH is required to neutralize 200 ml of 4.00 M HCl?
Thursday, June 16, 2016 by Anonymous

chemistry
Write the oxidation and reduction half-reactions for a silver-chromium voltaic cell. Identify the anode, cathode, and the direction of electron flow. Ag+ + e-  Ag Cr  Cr2+ + 2e- or Cr  Cr3+ + 3e- ????? Which is the correct equation for the chromium side...
Thursday, June 16, 2016 by S

CHEMISTRY
Why is I- a stronger reducing agent than F-?
Thursday, June 16, 2016 by Jordan

Chemistry
Consider the following reaction: CO(g)+2H2(g)⇌CH3OH(g) This reaction is carried out at a specific temperature with initial concentrations of [CO] = 0.27 M and [H2] = 0.49 M. At equilibrium, the concentration of CH3OH is 0.11 M. Find the equilibrium constant at this ...
Thursday, June 16, 2016 by Donnie

Chemistry
what is the percent by mass of a solution by dissolving 200 g of NaCI in 500 mL of water?
Wednesday, June 15, 2016 by Annyssa

Chemistry
Considering only the molecular orbitals formed by combinations of the s atomic orbitals in the valence shell, how many molecular orbitals can be formed by 5000 sodium atoms?
Wednesday, June 15, 2016 by Jack

Chemistry 171 Lab
Suppose we collect hydrogen gas, H2(g), over water at 21◦C in a vessel with total pressure of 743 Torr. If the hydrogen gas is produced by the reaction of aluminum with hydrochloric acid: 2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g) what volume of hydrogen gas will be ...
Wednesday, June 15, 2016 by Rae

Chemistry
the question says: Calculate the mass of soap (NaC17H35COO) which contains 1.25 grams of Carbon. Do I use the percentage composition of soap and the mole?
Tuesday, June 14, 2016 by Lauren

chemistry
A reaction has a first order rate constant of 6.11x10-5 s-1 at 25C and 0.00221 s-1 at 85oC. What is the value of the rate constant at 63oC?
Tuesday, June 14, 2016 by Basil

Chemistry
Combustion of 1g of an organic compound known to contain C, H and O produces 2.36g CO2, 0.64g H2O. What is the empirical formula?
Tuesday, June 14, 2016 by Marie

Chemistry
How much heat is needed to raise the temperature of 5.58 kilograms of iron from 20.0°C to 1000.0°C? Specific heat of iron is 450,000 J/(kg x °C). Type the correct answer to 3 significant digits.
Tuesday, June 14, 2016 by Sylvie

chemistry
_____ H2C2O4 + _____ NaOH ______Na2C2O4 + _____ H2O
Tuesday, June 14, 2016 by jamie K

chemistry lab
Why do we have to weight the beaker with salt and water before dissolving the Nacl ? why is it incorrect to weight it after we dissolve it
Tuesday, June 14, 2016 by terenlo

Chemistry
A sample of beer is 4.6 % by mass C2H5OH. The density of beer is 0.93 g/ml. What is the molar concentration of C2H5OH in this sample of beer? a. 9.7 x 10-4 b. 1.13 x 10-4 c. 0.975 M d. 1.13 M I did 0.046x930 g/L =42.78 mass alcohol 42.78/molar mass of C2H5OH (46.068) = 0.928 ...
Tuesday, June 14, 2016 by TS

Chemistry
The gas phase reaction X+Y⇄ Z is first order in Y and second order in X. If the concentration of X is double and concentration of Y is tripled. The reaction rate would be increase by a factor of: then, Rate= k [x]^2[y] --> k[x]^4[y}^3 is this the correct line of ...
Tuesday, June 14, 2016 by ED

CHEMISTRY
If you used only photons that were dropping from the n = 6 shell to the n = 1, how many of these photons would be required to keep a 100 Watt light bulb lit for 10 minutes?
Monday, June 13, 2016 by Jessica

chemistry
how is copper 2 sulphate formed from copper oxide and sulpheric acid and why is it formed?
Monday, June 13, 2016 by anonymous

chemistry
why is lead 2 iodide produced from the reaction of lead 2 nitrate and potassium iodide?
Monday, June 13, 2016 by anonymous

Chemistry
If you were told that a ball had a wavelength of 5 x 10-26 nm at a velocity of 60 mph, what would be the mass of that ball in pounds?
Monday, June 13, 2016 by Jessica

Chemistry
Prepare M/20 oxalic acid solution.Using this solution, find molarity, strength, and percentage purity of the sodium hydroxide solution.
Monday, June 13, 2016 by Sara

chemistry
How would you prepare 3.5 L of a 0.9M solution of KCl? A. Add 23 g of KCl to a 3.5 L container; then add enough water to dissolve the KCl and fill the container to the 3.5 L mark. B. Add 233 g of KCl to a 3.5 L container; then add enough water to dissolve the KCl and fill the...
Monday, June 13, 2016 by donna

Chemistry
I have 25 million gallons of water at a pH of 6.5. I add 17.4 million gallons of 12.5% by wt sodium hypochlorite (NaClO) at a pH of 12.5 to this water. What will my pH of my final solution be? It's been about 5 years since I took chemistry and I just don't remember how...
Monday, June 13, 2016 by Kelsey

chemistry
4NH3 + 5O2 --> 4NO + 6H2O 170g of ammonia (NH3) are allowed to react with 384g of O2. how many moles of NO is produced? and also how many grams of NO will be produced?
Monday, June 13, 2016 by shriya

chemistry
C3H8 + 5O2 --> 3CO2 + 4H2O 22 moles of propane (C3H8) react with 200 moles of oxygen gas. how many moles of the non limiting reactant remain?
Monday, June 13, 2016 by shriya

analaytical chemistry
a student mixes equal volume of 1 molar tin chloride and coper sulfate and observe tha no preciptate forms .then the students mxis equal volume of 1molar solution of zinc sulfate and tin floride and observe the formation of precipitate .which compound is precipitate
Monday, June 13, 2016 by Gebru

chemistry
How can diamond be formed artificially
Monday, June 13, 2016 by udeh

Chemistry
A Chemist wanted to determine the percentage of calcium carbonate in a sea shell. He collected a number of sea shells which he crushed into a fine powder. To 2.65 grams of sea shell powder he added 25.0mL of 5.0M Hydrochloric acid. When all the fizzing ceased, he filtered the ...
Monday, June 13, 2016 by James

Chemistry
50.00mL of 0.250M hydrochloric acid was added to 25.00mL of 0.300M potassium hydroxide. Calculate the pH of the resulting solution.
Sunday, June 12, 2016 by Tommy

Chemistry
If you have a properly adjusted hot flame, which is pale blue with three distinct comes, what is observed if the GAS CONTROL valve is slightly closed versus what's observed if the AIR CONTROL valve is slightly closed? Please Explain.
Sunday, June 12, 2016 by Christy

CHEMISTRY
Calculate the hydroxyl ion concentration in a solution of almond extract ofph.3.8 state wether almond is acidic or basic
Sunday, June 12, 2016 by EUNICE

chemistry
caculate the molar concentration of 1ppm solution of NaCl?
Sunday, June 12, 2016 by uzma jan

chemistry
calculate the normality of 5.56 grams of K2Cr2O7 dissolved in 500 mL
Sunday, June 12, 2016 by uzma

chemistry
calcuate the normality of 0.2M solution of h3p04 ?
Sunday, June 12, 2016 by Anonymous

Science Chemistry
A sample of beer is 4.6% by Mass C2H5OH. The density of beer is 0.93 g/mL. What is the molar concentration of C2H5OH in this sample of beer?
Sunday, June 12, 2016 by Kay

chemistry
If you had a carbonyl bonded to an O on one side and an OH on the other side, would the whole functional group be an ester or a carboxylic acid?
Sunday, June 12, 2016 by Anonymous

chemistry
Butanoic acid consists entirely of C, H and O. Upon combustion, a 0.3164g sample of butanoic acid produces 0.6322g CO2 and 0.2588g H2O. Determine the empirical formula of butanoic acid I don't want the answer just direction on how to solve this pls
Saturday, June 11, 2016 by balanciaga

chemistry
In a titration, 25.0 mL of KHP is titrated to the equivalence point with NaOH. The final solution volume is 45.5 mL. What was the volume of NaOH used in the titration? 25.0 mL 20.5 mL 70.5 mL 45.5 mL
Saturday, June 11, 2016 by yuliette

Chemistry
The standard disposable propane cylinders for use with camp stoves, lanterns, portable barbecues, etc, contain 355 g of propane. Calculate the total energy available from one of these cylinders.
Saturday, June 11, 2016 by Melanie

chemistry lab
Was the density you determined accurate, taking into account the total instrument uncertainty? I got 0.778 g/ml the theoretical value is 0.789 g/ml the instrumental uncertainty was 0.2% How do I know if its accurate ?? please help
Friday, June 10, 2016 by nevadaschool

chemistry
in a parallel plate capacitor the separation between the plates is 3mm with air between them. now a 1mm thick layer of a material of dielectric constant 2 is introduced between the plates due to which capacitance increases. In order to bring the capacitance to the original ...
Friday, June 10, 2016 by Anushka

Chemistry
Writing the net ionic equation for sodium fluoride+hydrochloride, magnesium iodide + lead (II) acetate sliver (I) acetate + potassium iodide nickel (II) sulfate + barium chloride barium acetate + ammonium sulfate barium hydroxide +aluminum bromide zinc iodide + potassium ...
Friday, June 10, 2016 by Lesley

chemistry
equal moles of ethane and hydrogen are mixed in container at 25 c what will be the pressure exerted by hydreogen?
Friday, June 10, 2016 by Musfera iqbal

Chemistry
Why ionic compounds have high melting points?
Friday, June 10, 2016 by Umair

chemistry
Information Set 4: Consider the reaction between 500 mL of 0.100 mol L–1 Pb(NO3)2(aq) and 500 mL of 0.200 mol L–1Na2CrO4(aq).  Ksp for PbCrO4 (s) is 2.8 x 10–13. What volume of 0.100 mol L–1 lead nitrate solution would give the ...
Thursday, June 9, 2016 by duke

chemistry
Iron(III) oxide can be reduced to metallic iron by heating it in the presence of carbon. Balance the following equation, then determine the ratio of C to Fe in the reaction? Fe2O3 + C → Fe + CO2?
Thursday, June 9, 2016 by madison

chemistry
Chromium (III) iodate has a Ksp at 25°C of 5.0 x 10–6. 125 mL of a solution contains 0.0050 mol L–1 Cr (III) ion. When 75.0 mL of the NaIO3 solution have been added, what is the concentration of the Cr(III) ion remaining in solution? not sure how ...
Thursday, June 9, 2016 by James

Chemistry
What is the percent of aluminum in Al2(SO4)3? A. 15.8% B. 28.1% C. 56.7% D. 54.0% C?
Thursday, June 9, 2016 by quick help please

Math
In a class of 100 students, 40 offer Biology and 10 offer Chemistry and Biology .10 offer Physics and Chemistry , and 30 offer Physic and Biology . Each student offer at least one of the three subjects. The number of students who offer Biology is equal to those who offer ...
Thursday, June 9, 2016 by Delson

chemistry
what fraction of voids are occupied by sp3 carbon in diamond
Thursday, June 9, 2016 by Anushka

Chemistry
A solution of acetic acid, 1.0 mol L–1 CH3COOH, contains sodium acetate, NaCH3COO. The percent ionization of the above solution is 0.25%. The Ka for acetic acid is 1.8 x 10–5. Which of the following is the concentration of NaCH3COO in acetic acid? So i use ...
Thursday, June 9, 2016 by luis

chemistry
The Kb of ammonia is 1.8 x 10–5. What is the percent ionization of a solution of ammonia, 0.50 mol L–1 NH3, that contains 0.020 mol L–1 of ammonium nitrate, NH4NO3? when i use the ICE table i don't end up with an unknown so im not sure what to...
Thursday, June 9, 2016 by James

chemistry
At equilibrium, a solution of formic acid at 25°C has a pH of 2.18. The pKa of formic acid, HCOOH, is 3.74. Which of the following is the initial concentration of the solution? Not sure what to do my thoughts: use henderson hasselback equation pH = pKa + log [conj ...
Wednesday, June 8, 2016 by James

chemistry
. Which of the following is not a way an atom can achieve stability?
Wednesday, June 8, 2016 by donna

Math
in a class of 60 students 30 like maths 25 like physics 30 like chemistry. if 10 like both physics and maths 5 like maths and chem and 5 like phy & chem and 3 like all the subjects. find student like none of subject if 100 students were surveyed
Wednesday, June 8, 2016 by Anonymous

Math
in a class of 60 students 30 like maths 25 like physics 30 like chemistry. if 10 like both physics and maths 5 like maths and chem and 5 like phy & chem and 3 like all the subjects. find student like none of subject of if 100 students were surveyed
Wednesday, June 8, 2016 by Dp

Chemistry
When the equation Fe + O2→Fe2O3 is balanced, the coefficient for O2 is: A. 4 B. 3 C. 1 D. 2 D?
Wednesday, June 8, 2016 by quick help please

Chemistry
A catalyst is: A. a solid product of a reaction. B. one of the reactants in a single-replacement reaction. C. not used up in a reaction. D. the product of a combustion reaction. C?
Wednesday, June 8, 2016 by quick help please

Chemistry
In order for the reaction 2Al(s) + 6HCl(aq)→2AlCl3(aq) + 3H2(g) to occur, which of the following must be true? A. Al must be above Cl on the activity series. B. Al must be above H on the activity series. C. Heat must be supplied for the reaction. D. AlCl3 must be a ...
Wednesday, June 8, 2016 by quick help please

Chemistry
The equation Ba(s) + HCl(aq)→BaCl2(aq) + H2(g) is an example of which type of reaction? A. double-replacement B. combustion C. single-replacement D. decomposition C?
Wednesday, June 8, 2016 by quick help please

Chemistry
At 25°C, the methylaminium ion, CH3NH3+, has a Ka of 2.0 x 10–11. Which of the following is the pH of a 0.15 mol L–1 solution of methylamine? i tried out two methods because im not getting the right answer: H20 + Ch3Nh2 -> CH3NH3+ + OH- I made a...
Wednesday, June 8, 2016 by Please help I tried for so long!

chemistry
The pKb of ammonia, NH3, is 4.74 at 25°C.  Which of the following is the Ka of the ammonium ion, NH4+? not sure what to do, this is what i have i guess: kb = -log 4.74 ----- pKa + pKb = 14 pKa = 9.26 ka = -log 4.26 = -0.676 ----- Ka = [NH4+][OH-]/ [NH3]
Wednesday, June 8, 2016 by chem101

chemistry
If at moment t=0 ,separation between cars is 100m.The separation between them at the moment t=2s can be?
Wednesday, June 8, 2016 by abhay

Analytical Chemistry
How do we do the calculations when carrying out an experiment on titrating 99% of 0.1molar of NaOH and 99% of 0.1molar of Sulphuric acid in a 1 litre?
Wednesday, June 8, 2016 by Anonymous

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Homework Help: Science