Wednesday
August 24, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
Determine the pH of a solution containing 1.00 mol/L of HCN (Ka = 5.00×10–10) and 5.00×10–2 mol/L of HCl. It will be the best for me if you give me the answer of this problems.
Saturday, July 2, 2016 by Anonymous

chemistry
Calculate the pH of a solution obtained by mixing 50 mL of NH3 0.1 M (Kb = 1.8•10–5 mol/L) and 25 mL of HCl 0.2 M.
Saturday, July 2, 2016 by Anonymous

chemistry
Calculate the pH of 0.3 M HCl solution. Calculate the pH when 100 mL of a 0.5 M solution of NaOH are added to 300 mL of the HCl solution.
Saturday, July 2, 2016 by Anonymous

chemistry
Calculate the pH of a solution obtained by mixing of 100 mL of a 10-3 M and 50 mL of a 10-2 M solution of CH3COONa.
Saturday, July 2, 2016 by Anonymous

Chemistry
A 360mg sample of sugar (molar mass of 180 g/mol) is dissolved in enough water to produce 200mL of solution. after the sugar is completely dissolved, you pour 50mL of this solution into a Burnette for use in an experiment. what is the molar concentration of sugar in the sample
Saturday, July 2, 2016 by Jacke

chemistry
Arrange the following groups of atoms in order of their increasing atomic radius: K,Rb,F,B,Be I think its F<B<Be<K<Rb someone can you correct me pls
Friday, July 1, 2016 by lo

Chemistry
Ammonium phosphate and nickel(II) nitrate solutions are mixed, what precipitates out?
Friday, July 1, 2016 by Anonymous

Chemistry
When the equation below is balanced and all coefficients are in the lowest, whole number ratio, the coefficients are: C2H6 + O2 ¨ CO2 + H2O I am currently doing an online worksheet to improve in chemistry and I am not quite understanding how to find the coefficients ...
Friday, July 1, 2016 by Anonymous

Chemistry
When the equation below is balanced and all coefficients are in the lowest, whole number ratio, the coefficients are: Bi + O2 ¨ Bi2O3
Friday, July 1, 2016 by Anonymous

Chemistry
Calculate the normality of 1.5M sulphuric acid
Friday, July 1, 2016 by Nishu

chemistry
how do I prepare 10% HCL from 50% HCL solution
Friday, July 1, 2016 by slindile

Chemistry
Balance both the atoms and charges of the following chemical equation: Ce4+ + S2 −→ Ce3+ + S This is what I came up with: 3Ce4+ + S2 −→ 4Ce3+ + 2S
Friday, July 1, 2016 by Mariah

chemistry
60 cm of hydrogen diffused through a porous membrane in 10 minutes. The same volume of gas G diffused through the same membrane in 37.4 minutes. Determine the relative molecular mass of
Thursday, June 30, 2016 by emmanuel

Chemistry
Given the balanced neutralization equation: H2SO4+2KOH→K2SO4+2H2O How many moles of potassium hydroxide (KOH) are required to neutralize 4.5 mol of sulfuric acid (H2SO4)? Assume that the sulfuric acid completely dissociates in water. 2 mols of KOH = 1 mol of H2SO2 4.5 ...
Thursday, June 30, 2016 by Mariah

chemistry/biochemistry
How can we calculate the HCO3- (bicarbonate ion) concentration in water in 25C pH7.0? I think we can use PV=nRT equation, but I am not sure. If pH is changed from 7.5 to 6.5 ( around pka 6.3 of CO2), how can change the HCO3- concentration? Thanks in advance.
Thursday, June 30, 2016 by Anonymous

Chemistry
100g of water is added into 10.6m NaOH solution.What is the mol fraction of NaOH in the diluted NaOH solution. Density of NaOH is 1.08g/ml
Thursday, June 30, 2016 by Que

Chemistry
How to convert 1.08g/ml to volume in ml?
Thursday, June 30, 2016 by Que

Chemistry
What quantity of NaOH should be dissolved in 15000l of water to obtain 4% concentration? proposed solution 4/100 * 15000 = 600
Thursday, June 30, 2016 by Mankah

chemistry
2Na+(aq) + 2OH−(aq) + Zn2+(aq) + 2NO3−(aq) → Zn(OH)2(s) + 2Na+(aq) + 2NO3−(aq) Write the net ionic equation for this precipitation reaction.
Wednesday, June 29, 2016 by malka

Chemistry
What will the pH of a solution be when 0.5447 L of NaOH (pH = 14.436) is added to 0.357 L of 2.01 M ascorbic acid (H2C6H6O6)? Not sure how to do this.
Wednesday, June 29, 2016 by Anonymous

chemistry
How would prove that sodiumhydroxied is a base without using litmus paper to test
Wednesday, June 29, 2016 by marvelous

Chemistry
How would you find out whether a sample of sodium chloride is pure or impure
Wednesday, June 29, 2016 by Anand

University of Liberia Chemistry 102
Using a current of 4.75A how many minutes does it takes to plate onto a sculpture 1.50g of CuSO4 solution?
Wednesday, June 29, 2016 by James

chemistry
Calculate the amount of water (in grams) that must be added to 5.00 g urea in preparation of 16.2% by mass solution.
Tuesday, June 28, 2016 by ain

Chemistry
What is the variable x in the following hydrate formula NaCl xH2O if the mass of sodium chloride is 58g and the mass of the water is 36g
Tuesday, June 28, 2016 by Kim

chemistry plz helpp!
A) 9.8g of an alcohol A completely reacts with an excess of sodium , and a gas is released. When the reaction ceases the volume of the gas is 1.6L measured at a temperature of 22ºc and under a pressure of 1 bar.  a- What gas is released in this reaction, how can it ...
Tuesday, June 28, 2016 by angy

Chemistry
100 g of water is added into 10.6 m NaOH solution. The diluted NaOH solution is then neutralized completely with H2SO4 solution. Density of NaOH is 1.08 g/ml. Calculate: i. the mol fraction of NaOH in the diluted NaOH solution. ii. mol of H2SO4 required.
Tuesday, June 28, 2016 by Ann

chemistry
Calculate the amount of water (in grams) that must be added to 5.00 g urea in preparation of 16.2% by mass solution.
Tuesday, June 28, 2016 by baizura

Chemistry
100g of water is added into 10.6M NaOH solution. The diluted NaOH then neutralized completely with H2SO4 . density of NaOH is 1.08g/ml . calculate the mole fraction of NaOH in diluted solution .
Tuesday, June 28, 2016 by Amy

chemistry
A) 9.8g of an alcohol A completely reacts with an excess of sodium , and a gas is released. When the reaction ceases the volume of the gas is 1.6L measured at a temperature of 22ºc and under a pressure of 1 bar. a- What gas is released in this reaction, how can it be ...
Tuesday, June 28, 2016 by angy

chemistry
If 5.00g of glucose were to react completely with an excess of oxygen, how many grams of carbon dioxide would be produced?
Tuesday, June 28, 2016 by helena15zgeo

Chemistry
100g of water is added into 10.6M NaOH solution. The diluted NaOH then neutralized completely with H2SO4 . density of NaOH is 1.08g/ml . calculate the mole fraction of NaOH in diluted solution .
Tuesday, June 28, 2016 by Amy

Chemistry
The volume of 18 molar concentrated H2SO4 that must be diluted with distilled water to prepare 10 liters
Monday, June 27, 2016 by Angel Kenkpen

chemistry
sorry,for the mistake. To 200mL of a 0.1M solution of a CH3COOH (Ka=1.8 x 10-5) 70mL of a 0.2M solution of NaOH have been added.calculate the pH before and after the NaOH addition.
Monday, June 27, 2016 by Anonymous

chemistry
I am trying to calculate the how amount of Tris-bicarbonate should be added in the reaction. I would like to have final volume of bicarbonate 10mM in 2ml reaction. I made Tris-base (1M, 100ml) and instead of HCl, CO2 was bubbling to set pH7.5. 0.1L*0.1M= 0.01 moles of Tris &#...
Monday, June 27, 2016 by chocho

chemistry
How could you prepare: a ) 2-chloropropane from 2-propanol? b) 2-butanone from 2-butanol? c) ethyl acetate CH3COOC2H5 from ethanol? d) 2-methyl-2-butene from 3-methyl-2-butanol?
Monday, June 27, 2016 by vicky

Organic Chemistry
Suppose 5.00 gram of a mixture of aspirin, caffeine, and acetanilide was dissolved in enough solvent (methylene chloride) to make a total of 100.00 mL volume. You took 10.00 mL from it and isolated its components using the same protocol you did in the lab. You obtained: ...
Monday, June 27, 2016 by David

Chemistry
I had to do a lab and had to calculate the molar mass for a substance with this equation MM=Mrt/pv but we had to calculate the mass of the substance and its temperature experimently. My question is why did we have to boil the liquide in a water containing becker. Why did we ...
Monday, June 27, 2016 by Gabby

chemistry
write the electron-dot formula for the following compound HCN,Co2,H2O@,O2,H2O
Monday, June 27, 2016 by maawiya muhammad diggie

Chemistry
Hi I got a question if we have An unknow but we have its molecular formula of that unknown compound can that Molecular formula ALWAYS tell us exactly what compound we have?
Monday, June 27, 2016 by Bonny

Chemistry
What is the amount of oxygen needed to create output 20gm?
Monday, June 27, 2016 by LABIBUL HASAN

Chemistry
Sorry, I have been stuck on this question. I would appreciate if someone could help me out. Approx how many mL of 0.25M BaCl2 solution would be required to precipitate all the sulfate if we assume the sample is pure sodium sulfate? Assume that the density of the barium ...
Sunday, June 26, 2016 by Mike

chemistry
How many degenerate orbitals have the following name? 2s 3p 5d 4p 5s I dont get this question
Sunday, June 26, 2016 by lo

Chemistry
The sulfate in a 0.2345 g sample of a mixture containing only K2SO4 (fm = 174.26) and Na2SO4 (fm = 142.04) is to beanalyzed by precipitating all the sulfate as barium sulfate, BaSO4 (fm = 233.39) by the addition of excess BaCl2. Na2SO4 + BaCl2 image from custom entry ...
Sunday, June 26, 2016 by Esraa

chemistry
Which of the following sets of quantum numbers are not allowed. For each incorrect set, state why it is incorrect. For each correct set, name the atomic orbital. i. n=4, l=3, ml =2, ms =-1/2 ii. n=2, l=1, ml =-1, ms =-1 iii. n=5, l=-4, ml =2, ms =+1/2 can you guys help me my ...
Sunday, June 26, 2016 by lo

chemistry
This statement is writing in my textbook can someone please explain to me what it mean: Determining the position of electrons, eliminates their wave properties.
Sunday, June 26, 2016 by lo

Chemistry
How much energy is released when 2.50g of NH3 rxs with excess N20 given the following 2NH3+3N2O -> 4N2_3H2O; DELTA(H)=-1010KJ. Please give work and setup :)
Sunday, June 26, 2016 by Alex

Chemistry
a 2.00 g sample of C6H402 is burned in a calorimeter whose heat capacity is 8kj/C. The delta T is +7.13 degrees C. What is the enthalpy change per mole?
Sunday, June 26, 2016 by Alex

Chemistry
64g of oxygen reacts completely with methane gas to form 44g of carbon dioxide gas and 36 g of water vapour. Calculate the amount of methane that takes part in the reaction .
Saturday, June 25, 2016 by Anonymous

CHEMISTRY
THIS IS THE 3RD TIME POSTING THIS, PLEASE HELP ME ANSWER THIS THE HOMEWORK IS DUE TONIGHT. Write formulas for the compounds that form from In (Assume In charge is 3+.) and each of the following polyatomic ion: NO−3, SO2−4, PO3−4 -3, -4, -4 ARE THE CHARGES. ...
Friday, June 24, 2016 by MELISSA

CHEMISTRY
THIS IS THE 3RD TIME POSTING THIS. PLEASE HELP ME ANSWER THIS. THE HOMEWORK IS DUE TONIGHT. Write formulas for the compounds that form from Sr and each of the following polyatomic ion: NO−3, SO2−4, PO3−4. THE -3, -4, -4 ARE THE CHARGES, CANT TYPE SUBSCRIPT ON...
Friday, June 24, 2016 by MELISSA

CHEMISTRY
Write formulas for the compounds that form from Sr and each of the following polyatomic ion: NO−3, SO2−4, PO3−4. APPARENTLY SrNO6, SrSO4 , Sr3PO8 is wrong
Friday, June 24, 2016 by MELISSA

CHEMISTRY
Write formulas for the compounds that form from In and each of the following polyatomic ion: NO−3, SO2−4, PO3−4. (Assume In charge is 3+.) InNo9, InSO6, AND InP4 is wrong
Friday, June 24, 2016 by MELISSA

CHEMISTRY
Provide the name of the oxyanion of the acid HNO2(aq) I ENTERED Carbonate ion BUT ITS WRONG
Friday, June 24, 2016 by MELISSA

Chemistry
Use the periodic table to answer this question. A student dissolves 24.2 g of NaCl in 500 mL of water. Another student dissolved 24.2 g of KI in 500 mL of water. Why do the two solutions have different molarities? The volumes of the solutes differ. The final volumes of ...
Friday, June 24, 2016 by Noah Love

Chemistry
The solubility of sodium chloride is 35.9 g/100 g H2O at 20°C. 35.9 g of sodium chloride are added to 100 g of water, and all of it dissolves. Another solution is made from the same amount of salt and the same amount of water. This time some solid remains undissolved. What...
Friday, June 24, 2016 by Amanda Perry

CHEMISTRY
Write formulas for the compounds that form from In and each of the following polyatomic ion: NO−3, SO2−4, PO3−4. (Assume In charge is 3+.) In(+3 charge) NO3(-1 CHARGE) SO4(-2 charge) P4(-3 charge) Re posting this a little differently. hopefully someone can ...
Friday, June 24, 2016 by MELISSA

CHEMISTRY
Write formulas for the compounds that form from Sr and each of the following polyatomic ion: NO3 −1, SO4 −2, PO4 −3. SR (+3 CHARGE) NO3(-1 CHARGE) SO4(-2 CHARGE) PO4(-3 CHARGE) Re posting this question. hopefully someone can help me answer this now. Please ...
Friday, June 24, 2016 by MELISSA

Chemistry
What is the theoretical yield of Fe2(SO4)3 if 20.00 g of FePO4 reacts with an excess of Na2SO4?
Friday, June 24, 2016 by Jacke

CHEMISTRY
Write formulas for the compounds that form from In and each of the following polyatomic ion: NO−3, SO2−4, PO3−4. (Assume In charge is 3+.) InNo9, InSO6, AND InP4 is wrong
Friday, June 24, 2016 by MELISSA

CHEMISTRY
Write formulas for the compounds that form from Sr and each of the following polyatomic ion: NO−3, SO2−4, PO3−4. APPARENTLY SrNO6, SrSO4 , Sr3PO8 is wrong
Friday, June 24, 2016 by MELISSA

Science-chemistry
an alloy of metal A and B in the eatio of 2:5 and weighs 36g the percentage of metal A is 22.22% if atomic mass of A is 40 then atomic mass of metal B is
Friday, June 24, 2016 by Sukrit

chemistry
What volume of 6M NaOH needed to prepare 250ml 0.1M NaOH?
Thursday, June 23, 2016 by alfa

Chemistry PLS HELP
The cover plate is removed from the gas jars shown iin the diagram. Nitrogen dioxide is a brown gas. After several days, the color of the gas is the same in both of the jars. What explains this change? So the picture shows this jar and nitrogen and nitrogen dioxide is ...
Thursday, June 23, 2016 by Cheezel

chemistry
Find the molar solubility of BaCrO4 (Ksp= 2.1 × 10−10) in 3.5 × 10−3 M Na2CrO4
Thursday, June 23, 2016 by becca

Chemistry
X forms an oxide X2O3 , 0.36 grams of X forms 0.56 grams of X2O3 .so that atomic weight of X is
Thursday, June 23, 2016 by Soujanya

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

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Homework Help: Science