Tuesday
September 27, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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 dont 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 dont end up with an unknown so im not sure what to do. ...
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

chemistry
What is the difference between molecular compounds, covalent compounds and covalent bounds
Wednesday, June 8, 2016 by AMELIA

chemistry
The equilibrium constant for the reaction Cu3(PO4)2(s)    3 Cu2+(aq)  +  2 PO43–(aq) is K = 1.40 x 1​0–37.  Suppose that a beaker is filled to 1 L with a solution containing [Cu2+] = [PO43–] = 10.0 nM...
Tuesday, June 7, 2016 by jess

chemistry
Consider the information given below ΔH⁰/ kJmol-1 Enthalpy of lattice formation for CaF2 -2611 Enthalpy of hydration for Ca2+ ions -1650 Enthalpy of hydration for F- ions -506 Using the information given above, calculate the enthalpy of solution for CaF2
Tuesday, June 7, 2016 by chansa

chemistry
Acids and bases • What is an acid? • A 500cm3 solution containing 1.9g of a weak acid HA has a pH of 3.50. Calculate the molar mass of the acid, given that it has a Ka of 2.0 × 10-6moldm-3 • Calculate the pH of the following: • 0.002moldm-3 NaOH &#...
Tuesday, June 7, 2016 by chansa

chemistry
a) Define the following terms: • Electronegativity • Bond polarity • Ionization energy b) What is the difference between ionic bonds, covalent bonds and polar covalent bonds? Give two examples of each c) Draw Lewis structures for each of the following: • ...
Tuesday, June 7, 2016 by chansa

Chemistry
Which symbol correctly represents an element (D) whose atoms contain 15 protons and 20 neutrons? A. 20/15 D B. 15/20 D C. 35/15 D D. 15/35 D C?
Tuesday, June 7, 2016 by quick help needed

Chemistry
Which of the following statements is not consistent with the results obtained in Rutherford’s gold foil experiment? A. The nucleus of an atom is positively charged. B. The nucleus of an atom contains almost all the mass of the atom. C. Atoms are composed mainly of empty ...
Tuesday, June 7, 2016 by quick help needed

Chemistry
How would you prepare pure dry crystals of potassium trioxocarbonate (v)
Monday, June 6, 2016 by Jenifer

Chemistry
How many moles are in 7.5x10^24 molecules of carbon dioxide? Grams?
Monday, June 6, 2016 by Jake

chemistry
when measuring latent heat, why should your final temperture be the minimum temperature reached by the calorimeter?
Monday, June 6, 2016 by asasasas

chemistry
'Aluminium displaces hydrogen from dilute HCl whereas silver does not. The E.M.F. of a cell prepared by combining Al /Al 3 andAg/Ag is 2.46 V. The reduction potential of silver electrode is 0.80 V. The reduction potential of aluminium electrode is :
Monday, June 6, 2016 by Anushka

Chemistry
An aqueous solution that 2.00 M in AgNO3 is slowly added from a buret to an aqueous solution that is 1.00×10−2 M in Cl− and 0.260 M in I−. When the second ion begins to precipitate, what is the remaining concentration of the first ion? I know that the ...
Sunday, June 5, 2016 by Sydney

Chemistry
How many grams of cesium chloride (CsCl) will be needed to make 750. mL of a 0.100 M CsCl aqueous solution? The formula mass of CsCl is 168.36 g/mol
Sunday, June 5, 2016 by Eddie

chemistry
Propane, C3H8, reacts with oxygen according to the following balance equation. If 44 grams of propane react completely with sufficient oxygen, how many grams of water are produced?
Sunday, June 5, 2016 by salende

chemistry
a solution of nickel sulphate in which nickel rod is dipped is diluted 10 times. the reduction potential of Ni at 298 K is?
Sunday, June 5, 2016 by Anushka

chemistry
If 0.5 moles of bacl2 is mixed with 0.2 moles na3po4 then maximum no.of moles of nacl formed is?
Sunday, June 5, 2016 by abhay

Chemistry
A student estimated a mass to be 250 g but, upon carefully measuring it, found the value to be 240 g. What is the percent error of the estimated mass if the measured value is the accepted one? A. 4.2% B. 4.0% C. -4.2% D. -4.0% D?
Sunday, June 5, 2016 by quick help needed

chemistry
How many significant figures are in the measurement 603.040 g? A. 3 B. 4 C. 5 D. 6 C?
Sunday, June 5, 2016 by quick help needed

chemistry
A current of 96.5 A is passed for 18 min between nickel electrodes in 500 mL solution of 2M Ni(NO3)2. The molarity of solution after electrolysis would be
Sunday, June 5, 2016 by Anushka

chemistry
Which of the following is not a part of the scientific method? A. hypothesizing B. experimenting C. observing D. proving D?
Sunday, June 5, 2016 by quick help needed

Analytical Chemistry
Could someone show me step by step how to solve this type of problem? I have to do several of them, and would love to understand what is actually happening! Thank you so much in advance, I appreciate your help and time! Calculate the weight percent of ascorbic acid in a tablet...
Sunday, June 5, 2016 by DeeDee

Chemistry
How many ammonia liters of ammonia gas are produced when 85 grams of liquid nitrogen completely react? N2 + 3H2 = 2NH3
Saturday, June 4, 2016 by Macario

Chemistry
For the equilibrium system below, which of the following would decrease the concentration of 𝑃𝐶𝑙3(𝑔)?​ 𝑃𝐶𝑙3(𝑔) + 𝐶𝑙2(𝑔) ↔ 𝑃𝐶𝑙5(𝑔) + 45𝑘&#...
Saturday, June 4, 2016 by Help:(

Chemistry
7. For the equilibrium system below, which of the following would increase the concentration of 𝐻2𝑂(𝑔)? 𝐶(𝑠) + 𝐻2𝑂(𝑔) + 131𝑘𝐽 ↔ 𝐶𝑂(𝑔) + 𝐻2(𝑔) a. ...
Saturday, June 4, 2016 by Urgent

Chemistry
One of the issues caused by acid rain is the lowering of pH of small lakes, which leads to the death of numerous aquatic fish and plant species. Calcium oxide, commonly known as lime, is frequently used to temporarily remediate lakes that have been acidified by acid rain. ...
Saturday, June 4, 2016 by John Lee

chemistry
aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide a. balance the chem eqn for this rxn Al2S3+6H2O = 2Al(OH)3+3H2S b.how many g of water are needed in the rxn to produce al(oh)3? what is the formula i use here?? c. how many g of al(oh)3 are ...
Saturday, June 4, 2016 by shi

Chemistry Homework
Backpackers often use canisters of white gas to fuel a cooking stove’s burner. If one canister contains 2.45dL of white gas, and the density of the gas is 0.720g/cm3, what is the mass of the fuel in kilograms? So Volume=2.45dL(10L/1dL)=24.5L(1000/1)=245​00cm^3 D=m/v...
Friday, June 3, 2016 by Leo

Chemistry
What is the mobile phase in this experiment? A) 10% 6M NaOH and 90% acetone B) 10% 6M HCl and 90% acetone C) 10% 5M KCl and 90% methanol D) 10% 5M KCl and 90% acetone Gel electrophoresis is an example of which type of chromatography? A) Column chromatography B) Gas ...
Friday, June 3, 2016 by Jon Riley

Chemistry
How many ammonia liters of ammonia gas are produced when 85 grams of liquid nitrogen completely react? N2 + 3H2 = 2NH3
Friday, June 3, 2016 by Macario

chemistry
Suppose a substance has been prepared that is composed of carbon, hydrogen, and nitrogen. When 0.1156 gram of this compound is reacted with oxygen, 0.1638 gram of carbon dioxide (CO2) and 0.1676 gram of water (H2O) are collected. Assuming that all the carbon in the compound ...
Friday, June 3, 2016 by Chansa

chemistry
show by calculation of z the behavior of (.25 mole) gas sample at the following conditions (ideal or real)at temperature 100c 1-p=0.25 v=12
Friday, June 3, 2016 by kamal

Chemistry
The combustion reaction of propane is described by the reaction. C3H8 + 5O2 → 4H2O + 3CO2. How many moles of O2 are required to generate 3 moles of CO2? 2.5 moles 3 moles 4 moles 5 moles
Friday, June 3, 2016 by Wesley

Chemistry
How many ammonia liters of ammonia gas are produced when 85 grams of liquid nitrogen completely react? N2 + 3H2 = 2NH3
Friday, June 3, 2016 by Macario

chemistry
a compound or solute with molecular mass 36?
Friday, June 3, 2016 by Anonymous

chemistry
a compound or solute will molecular mass 36?
Friday, June 3, 2016 by kartik

Chemistry
How many electrons are present in 0.002 moles of O--?
Friday, June 3, 2016 by Abhinav

Chemistry/- Dr.Bob222
A voltaic cell consists of a Zn/Zn2+ half-cell and a Ni/Ni2+ half-cell at 25 C. The initial concentrations of Ni2+ and Zn2+ are 1.50 M and 0.10 M, respectively. a. What is the initial cell potential? My answer: 0.56 B b. What is the cell potential when the concentration of Ni2...
Thursday, June 2, 2016 by Nevaeh

chemistry
I was given the following problem: what is the normality of a solution containing 6 grams of H2SO4 in a 200ml solution? my teacher obtained a normality of 39normals while I took into account that I had two hydrogen free and obtained a result of 0.6 N, who's right?
Thursday, June 2, 2016 by Paul

Chemistry
a 0.20 mol/l solution of weak base hpo4 has a ph of 9. find the Kb
Thursday, June 2, 2016 by Dawn

Chemistry
A buffer was prepared by mixing 0.1 M ch3cooh with 0.1M ch3cooNa in the ratio 8:2. Calculate ph after the addition of 2mL of 0.1 M HCl? When you do the 8:2 ratio and add 2 mL of 0.1 M HCl, the buffer is gone and you are left with 1*10^-3 moles of ch3cooh. How would you ...
Thursday, June 2, 2016 by Bobby

chemistry
Calculate the loss in mass if 20.2g of KNO3 crystals was completely decomposed(K=39,N=14,O=16
Thursday, June 2, 2016 by Deborah

Chemistry
Check my answers 63. What type of bond links the monomers together in a polymer? Poly bond Covalent bond Ionic bond Hydrogen bond*** 64.What is the change in atomic mass when an atom emits a beta particle? decreases by 1*** increases by 1 decreases by 2 remains the same 65. ...
Thursday, June 2, 2016 by Kayla

Chemistry
The acetate buffer were prepared by mixing 0.1 M ch3cooh with 0.1M ch3cooNa in the ratio 8:2 and 2:8. Calculate the resulting ph after the addition of 2mL of 0.1 M HCl to 10 ml of buffer 8:2 and 4ml of 0.1 M NaOH to 10 ml of buffer 8:2.
Thursday, June 2, 2016 by Bobby

Chemistry
You are given Ka of carbonic acid is 4.3 x10^-7. This means that Carbonic acid is a good hydrogen-ion acceptor*** good hydrogen-ion donor poor hydrogen-ion acceptor poor hydrogen-ion donor
Thursday, June 2, 2016 by Kayla

Chemistry
Calculate the molality of a solution prepared by dissolving 225.5 g KNO3 in 825mL of water. Show your work
Thursday, June 2, 2016 by Kayla

chemistry
A certain first order reaction has a rate constant of 5.68 x 10–3 s–1 at 139°C and a rate constant of 8.99 x 10–1 s–1 at a temperature of 215°C. Ea = 111 kJ mol– q1) What is the value of the rate constant at 275°C? q2) ...
Thursday, June 2, 2016 by jane

Chemistry
Calculate the pH of a mixture of 20.0 mL of 0.150 M HCl and 10.0 mL of 0.300 M NaOH.​[7.00]
Thursday, June 2, 2016 by Sihle

Chemistry
98.4 * (1/2)^(19/3.8) = 3.075 g CH3COOH*** H2PO4^– LiOH NH3
Wednesday, June 1, 2016 by Kira

Chemistry
What is the one standard atmosphere of pressure in kilospascals 0 kPa 1 kPa*** 101.3 kPa 760 kPa
Wednesday, June 1, 2016 by Nikkie

Chemistry
Use an analogy from everyday life that can define the term half-life
Wednesday, June 1, 2016 by Nikkie

Chemistry
Why does the mass and charge of an alpha particle make it less penetrating than a beta or gamma? Discuss both the mass and the charge
Wednesday, June 1, 2016 by Nikkie

Chemistry
How can an element be artificially transmuted? Give an example that has an element and what it is transmuted into
Wednesday, June 1, 2016 by Nikkie

Chemistry
The radioisotope radon-222 has a half-life of 3.8 days. How much of a 98.4 g sample of radon -222 would be left after approximately 19 days?
Wednesday, June 1, 2016 by Nikkie

chemistry
In a certain experiment, the rate constant, k, was measured as a function of the temperature, T.  Two data points were as follows: (A) 25°C, 1.1 x 10–5 min–1, and (B) 225°C, 2.4 x 10-2 min–1. The student who performed the experiment then ...
Wednesday, June 1, 2016 by jessica

Chemistry
At 425°C, a reaction has a rate constant of 7.7 x 10–4 s–1 and has an activation energy of 275 kJ mol–1. What is the frequency factor? The answer is 2.9 x 1017 s–1 , I need help with working out I used arrhenius equation and rearranged ...
Wednesday, June 1, 2016 by jessica

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Homework Help: Science