Friday
February 24, 2017

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Maths
In a class of 80 students,53 study Art,60 study biology,36 study Art and biology,34 study Art and chemistry,6 study biology but not chemistry.Illustrate the information on a Venn diagram.Determine the number of students who study Art only And Chemistry only
Wednesday, February 8, 2017 by Nana Adwoa

Chemistry
Aluminum oxide contains 53% of Al. How much oxygen combines with 26.5g of aluminium to form aluminium oxide? Thank you
Wednesday, February 8, 2017 by Genevieve Agbey

Chemistry
Benzene (C6H6) has a normal freezing point of 5.50oC and a density of 0.88 g/mL. When 1.28 g of naphthalene (C10H8) is dissolved in 125 mL of benzene, the freezing point of the solution is 5.03oC. Determine the molal freezing point constant for this solvent.
Wednesday, February 8, 2017 by Sarah

Chemistry
Consider a one step reaction. Which of the following does not describe the activation energy of the process? The minimum amount of energy needed for a reaction to occur The energy difference between the starting point and the transition state The energy required to distort or ...
Wednesday, February 8, 2017 by Gerrard

Chemistry
A 17.7kg piece of zinc at 73 degrees celsius is placed in a container of water. The water has a mass of 23 kg and has a temperature of 13.4 degrees celsius before the zinc is added. what is the final temperature of water?
Tuesday, February 7, 2017 by Nate

Chemistry
What are at least 2' real world uses of colligative properties?
Tuesday, February 7, 2017 by Allison

Chemistry
1. Calculate the MOLALITY (m=mol/kg) of the salt water solution. Note: Include the mass of ice AND volume of water when calculating the TOTAL MASS of the solvent (water). (1ml of water=1g of water. Is my work correct? So what I did was, Knowing m=mol/kg for molality, the ...
Tuesday, February 7, 2017 by MJay.

Chemistry
What's the pH of 0.15M C3H6O3?
Tuesday, February 7, 2017 by Rafael

Chemistry
For the reaction CS2+3Cl2=CCl4+S2Cl2, calculate the percent yield if 719 g of CCl4 are produced when 410 g of CS2 react w/ an excess of chlorine. I have absolutely no clue on how to do this!! If I could get some help that would be great!!
Tuesday, February 7, 2017 by Sadie

Chemistry 2
The solubility of CO2 in water is 3.2 x 10^2 M at 25 C and 1 atm pressure. What is the Henry's Law constant for CO2 in mol/(L atm)? c=kP 0.25= kP p=kc p/k=kc/k =Px 1/k Please help!
Tuesday, February 7, 2017 by Brad

Chemistry
Hydrogen gas, H2, reacts with nitrogen gas, N2, to form ammonia gas, NH3, according to the equation 3H2(g)+N2(g)→2NH3(g) PArt 1: How many grams of NH3 can be produced from 3.26 mol of N2 and excess H2. Part 2: How many grams of H2 are needed to produce 13.17 g of NH3? part 3...
Tuesday, February 7, 2017 by Rose

chemistry
1. based on the equation below, how many liters of water can be produced from 8.5 L (assume that hydrogen is in excess) 2H2(g)+O2(g) --->2H2O(g)
Tuesday, February 7, 2017 by holly

Chemistry
1.38 mol HCl and 2.9 mol NaOH react accord- ing to the equation HCl + NaOH −→ NaCl + H2O . If the limiting reactant is HCl, determine the amount of excess reactant that remains. Answer in units of mol.
Tuesday, February 7, 2017 by Angel

Chemistry
How many representative particles are in 2.5 mol H2O2?
Tuesday, February 7, 2017 by Mercy

Chemistry Lab
Data and Calculations: 1. Volume of water in calorimeter: 100.0 mL 2. Mass of water in calorimeter (water's density 1.00g/mL): 100.0g 3. Initial Temperature of water in calorimeter:19.5 degrees Celsius 4. Final Temperature of water in calorimeter: 3.0 degrees Celsius 5. Final ...
Tuesday, February 7, 2017 by Coolest

Chemistry
1.38 mol HCl and 2.9 mol NaOH react accord- ing to the equation HCl + NaOH −→ NaCl + H2O . If the limiting reactant is HCl, determine the amount of excess reactant that remains. Answer in units of mol.
Tuesday, February 7, 2017 by Angel

Chemistry
Will increasing the temperature of H20 before dissolving Ca(IO3)2 affect how much Ca(IO3)2 is dissolved? I think this has something to do temperature and Le Chatelier's Principle and equilibrium. So, would more be dissolved at a higher temperature than at a lower temperature ...
Monday, February 6, 2017 by Minuet

chemistry
You are given a 500 mL stock solution of 10%CaCl2 and are askes to prepare a 50 mL solution of .5% CaCl2. How would you prepare it? Please show work
Monday, February 6, 2017 by morgan

Chemistry
A first order reaction ABC → AB + C has a rate constant of 0.0125 /s. If the initial concentration of ABC is 0.500 M, what is the concentration of ABC after 5 minutes? Note: do not include units in your answer, do not use scientific notation.
Monday, February 6, 2017 by Iguana

chemistry (ap)
What will be the reaction rate (formation of C) when the concentrations of A & B are 0.150 M and 0.250 M respectively?
Monday, February 6, 2017 by Yubellkis

CHEMISTRY
What will be the reaction rate (formation of C) when the concentrations of A & B are 0.150 M and 0.250 M respectively?
Monday, February 6, 2017 by Yubellkis

Chemistry
Calculate the pH of HCL if you have 10.0g in 5.0L of solution
Monday, February 6, 2017 by Jay

chemistry
in the laboratory, concentrated hydrogen chloride acid reacted with aluminium. hydrogen gas evolved was collected over water at 25 degree celcius and had a volume of 355 centimetre cube at a total pressure of 750mmHg.(the vapour pressure of water at 25 degree celcius equal to ...
Monday, February 6, 2017 by damilola

chemistry
Calculate the energy of a photon emitted when an electron in a hydrogen atom undergoes a transition from n=5 to n=1 in J.
Monday, February 6, 2017 by ariel

chemistry
How I doing electrolysis of aluminium cloraed?
Sunday, February 5, 2017 by aritra

chemistry
Al2Br6, xpress your answer as a chemical formula?
Sunday, February 5, 2017 by kaba

Chemistry
At what speed must a human weighing 150.0 lb be traveling in order to have a wavelength at 650 nm?
Sunday, February 5, 2017 by Piper

Chemistry
Calculate the number of valence electrons in BF3.
Sunday, February 5, 2017 by cool

Chemistry
Why was sublimation performed under reduced pressure?
Sunday, February 5, 2017 by Vivian

Chemistry
Calculate the pH values and draw the titration curve for the titration of 500 mL of 0.010 M acetic acid (pKa 4.76) with 0.010 MKOH. Calculate the pH of the solution after 490 mL of the titrant have been added.
Sunday, February 5, 2017 by Samantha

Chemistry
Calculate the new freezing point and the new boiling point of an aqueous solution that contains 40.5 g of Calcium Nitrate dissolved in 225 grams of water.
Sunday, February 5, 2017 by Anonymous

chemistry
Word equation of dissolving zinc in dilute susurphuric acid
Sunday, February 5, 2017 by emancy

Chemistry
A typical solid fertiliser for use with household plants and shrubs contains the elements N, P and K in the ratio of 15g: 30g: 15g per 100g of fertiliser. The recommended usage of fertiliser is 14g of fertiliser per 5dm^3 of water. What is the concentration of nitrogen atoms ...
Sunday, February 5, 2017 by Ta

Chemistry
Describe the procedure you would follow to determine the concentration of vitamin c in a sample if the volume of dcpip required to reach the end point were more than the 10-mL graduated cylinder could hold. The titration must still be carried out in the 10-mL graduated ...
Sunday, February 5, 2017 by Nicole

chemistry
Which of the following statements is false ? a) S is negative when water condenses at 100oC b) Ssurroundings is positive when water condenses at 100oC c) Suniverse is equal to zero when water condenses at 990C d) Suniverse increases when water condenses at 110oC
Sunday, February 5, 2017 by Mi

Chemistry
A closed bottle contains a solution of 5.0% by mass acetone [(CH3)2CO] in water. Calculate the vapour pressure (in kPa) of this solution at 25oC. The vapour pressure of pure water at 25oC is 3.17 kPa and that of pure acetone is 30.7 kPa.
Sunday, February 5, 2017 by Vanessa

Chemistry
Fireflies flash at a rate that depends on the temperature. At 29oC, the average rate is 3.3 flashes every 10 seconds, whereas at 23oC, the average falls to 2.7 flashes every 10 seconds. Calculate the "energy of activation" (in kJ/mol) for the flashing process.
Sunday, February 5, 2017 by Jacob

Chemistry
What type of solid is Ne? Metallic? Molecular? Ionic? or Covalent Network?
Sunday, February 5, 2017 by Coolest

Chemistry
What will be the mass of ferrous sulphide formed when 20 gram of pure sulphur reacts with iron ?
Sunday, February 5, 2017 by Pratik ravindra bachhav

Chemistry
How many grams of H2O are needed if 41.85g of O2 are to be produced from the reaction below? 2K2O2 + 2H2O = 4KOH + O2
Saturday, February 4, 2017 by Dezi

chemistry
A dilution is made during the preparation of a reaction mixture. The compounds are: 2.00 ml of 0.325 KMnO4, 7.50 ml of 0.155 M Oxalic acid, and 10.00 ml of H2O. What are the final concentrations of the compounds?
Saturday, February 4, 2017 by Yubellkis

Chemistry
PartA: What volume of 10.0M NaOH is needed to prepare a buffer with a pH of 7.79 using 31.52 g of TrisHCl? TrisHCl is a weak base and the molecular weight is 157.67 g/mol. I found the solution, it is 6.67 milliliters. Part B: "The buffer from Part A is diluted to 1.00 L. To ...
Saturday, February 4, 2017 by Fay

Chemistry
Consider a one step reaction. Which of the following does not describe the activation energy of the process? The minimum amount of energy needed for a reaction to occur The energy difference between the starting point and the transition state The energy difference between the ...
Saturday, February 4, 2017 by John

enviromental chemistry
If 10 ppm of nitrogen dioxide is present 1000 L of air at a pressure of 1 atm and temperature of 27 °C, what is the amount of ammonia necessary to react?
Saturday, February 4, 2017 by joe

Chemistry
The common picnic ant walks with a velocity of 0.01 meters per second (m/s). How long will it take an ant to walk across a 8 ft long picnic table, assuming it does not meet with an untimely demise along the way? (1 m = 39 in, 1 ft = 12 in) 8ft/1 X 12in/1in X 2.54cm/1in
Saturday, February 4, 2017 by Peyton

Chemistry
The photoelectric work function of a metal is the minimum energy needed to eject an electron by irradiating the metal with light. For calcium, this work function equals 4.34 x 10-19 J. If light with a wavelength of 256 nm impinges on a piece of calcium, what is the speed of ...
Saturday, February 4, 2017 by Piper

Chemistry
The photoelectric work function of a metal is the minimum energy needed to eject an electron by irradiating the metal with light. For calcium, this work function equals 4.34 x 10-19 J. If light with a wavelength of 256 nm impinges on a piece of calcium, what is the speed of ...
Saturday, February 4, 2017 by Piper

chemistry
In part B of my question, I was asked calculate the number of atoms in 0.462 mol of 13C (mass number of this Carbon is 13). I received the correct answer of 2.78E23 atoms. However, I do not know how to do Part C of my question, which asks "Based on your answer in Part B, how ...
Saturday, February 4, 2017 by rose

Chemistry
How many grams of urea would have to be dissolved in 250 grams of water to give it a freezing point of -4.degrees celcius
Saturday, February 4, 2017 by Amy

chemistry
Calculate the pH values and draw the titration curve for the titration of 500 mL of 0.010 M acetic acid (pKa 4.76) with 0.010 MKOH. Calculate the pH of the solution after 490 mL of the titrant have been added. Calculate the pH of the solution after 500 mL of the titrant have ...
Friday, February 3, 2017 by Crystal

Chemistry
Magnesium has three stable isotopes: 24Mg, 25Mg, 26Mg. The relative abundance of 24Mg is 79%. What are the relative abundances of 25Mg and 26Mg?
Friday, February 3, 2017 by Piper

CHEMISTRY
1. Not sure of how to do the calculations... Make a 0.200 m solution of NaCl in a 100. mL volumetric flask. ... Solution A's question or statement is the same but with M (molarity) Is this right? The small m means molality. If it were changed to capital M, then solution A's ...
Friday, February 3, 2017 by Allison

Chemistry
If 0.35 moles of SO3 is placed in a 1 dm3 flask and allowed to come to equilibrium at a high temperature, 0.207 mole of S03 remains. Calculate Kc For the reaction 2SO3 Double arrow 2SO2 +02
Friday, February 3, 2017 by Summit

Chemistry
its takes 145 mL of zinc nitrate to react completely with 175 ml of 1.5 M potassium hydroxide. what is the concentration if zinc nitrate?
Friday, February 3, 2017 by Annie

Chemistry
1. Not sure of how to do the calculations... Make a 0.200 m solution of NaCl in a 100. mL volumetric flask. ... Solution A's question or statement is the same but with M (molarity) Is this right? The small m means molality. If it were changed to capital M, then solution A's ...
Thursday, February 2, 2017 by A

chemistry
a student performs the lab on an unknown metal and obtain the following data
Thursday, February 2, 2017 by mary

Chemistry
Net ionic equation for the reaction of strontium nitrate and sodium carbonate.
Thursday, February 2, 2017 by Oto-obong

Chemistry
We did a lab about the heat hydration of sodium acetate with water. I got that the enthalpy of anhydrous sodium acetate is exothermic while the enthalpy of trihydrate sodium acetate is endothermic. Also that the enthalpy of the hydration of the sodium acetate salt is also ...
Wednesday, February 1, 2017 by Anonymous

chemistry
How to balanced chemical equation and identify the type of reaction for solid ammonium nitrate decomposes into dinitrogen monoxide gas and water
Wednesday, February 1, 2017 by judy

Chemistry
How many grams of CaCl2 are needed to produce 10.0 grams of NaCl?
Wednesday, February 1, 2017 by Jaeshon

chemistry
You are making 40g of a 29% (w/w) sucrose solution. what amount of sucrose and water would be used. each in grams please
Wednesday, February 1, 2017 by terry

Chemistry
An aqueous solution of volume, v1 cm3, contains a mass, mg,of a compound to be extracted. When shaken with v2 cm3 of an organic solvent, a certain proportion, x, of this compound dissolves. Derives an expression for x in terms of v1, v2 and the partition coefficient, k.
Wednesday, February 1, 2017 by Shariah

chemistry
A patient is prescribed 0.210 mg of a drug that is available in 70 μg tablets. How many tablets are needed? (Remember that the number of significant figures does not matter because the number of tablets is being counted.)
Wednesday, February 1, 2017 by savannah

Math, physics, chemistry
calculate total ionic strength of solution in which concentration of CuSO4 and Al2(SO4)3 is 0.1 molar
Wednesday, February 1, 2017 by Danish malik

chemistry
In the reaction K2CrO4(aq) + PbCl2(aq) → 2KCl(aq) + PbCrO4(s), how many grams of PbCrO4 will precipitate out from the reaction between 500.0 milliliters of 3.0 M K2CrO4 in an excess of PbCl2?
Wednesday, February 1, 2017 by Anonymous

Chemistry
Consider equation 3A+B=C+D. You react 4 moles of A with 2 moles of B. Which of the following is true? 1) Limiting reactant (L.R.) is one with higher molar mass 2) A is L.R. because you need 6 moles of A and have only 4 moles 3) B is L.R. because you have fewer moles of B than ...
Wednesday, February 1, 2017 by Rebecca

Chemistry
How many mL of SCN^-1 and water to put in a 10 mL solution with 5 mL of Fe^3+ already in it?... We're finding those values to make standard solutions of 0.00 mM FeSCN^2+ 0.020 " 0.040 " 0.060 " 0.080 " 0.100 " I know that you have to use M1*V1=M2*V2,but I'm not sure where to ...
Wednesday, February 1, 2017 by Savanna

chemistry
Robin the Research scientist prepares 100 mLs of a solution of 100 mM of Tris HCl. What is the pH? and part two for this question Calculate the pH when the scientist adds 100 ul of 50% NaOH
Tuesday, January 31, 2017 by Aarya Singh

Chem
2. Suppose a chemistry student made 2000. mL of 6.00 M HCl. He accidently spilled half of this solution on the floor. What is the Molarity of HCL left in the beaker? Explain the answer... - for this problem, would I use the eq'N, M1V1=M2V2. 3. What is the molarity of a sol'n ...
Tuesday, January 31, 2017 by Lina

Chemistry
Robin the Research scientist prepares 100 mLs of a solution of 100 mM of Tris HCl. What is the pH? and part two for this question Calculate the pH when the scientist adds 100 ul of 50% NaOH I am confused since we do not know the conjugate base concentration so how to solve for...
Tuesday, January 31, 2017 by Aarya Singh

chemistry
Calculate the pH values and draw the titration curve for the titration of 500 mL of 0.010 M acetic acid (pKa 4.76) with 0.010 MKOH. Calculate the pH of the solution after 490 mL of the titrant have been added. Calculate the pH of the solution after 500 mL of the titrant have ...
Tuesday, January 31, 2017 by Jasmine

Chemistry
Robin the Research scientist prepares 100 mLs of a solution of 100 mM of Tris HCl. What is the pH? I am confused since we do not know the conjugate base concentration so how to solve for the pH
Tuesday, January 31, 2017 by Aarya Singh

Chemistry
Calculate the number of liters of hydrogen gas at STP that could be produced by the reaction of 4.80g of magnesium with excess hydrochloric acid. Mg+HCl=MgCl2+H2
Tuesday, January 31, 2017 by Makenna

chemistry
How many mole of CL2 are needed to react with 2.0 mole Na?
Tuesday, January 31, 2017 by marisa

Chemistry
What volume is occupied by 100 g of air at room temperature (d = 1.20 g/L)?
Tuesday, January 31, 2017 by Alisa

chemistry
How many mole of CL2 are needed to react with 2.0 mole Na?
Monday, January 30, 2017 by marisa

Chemistry
cooking oil, a non-polar liquid, has a boiling point in excess of 200 degrees Celsius. Water boils at 100 degrees. how can you explain these facts, given the strength of water's hydrogen bonding?
Monday, January 30, 2017 by Quavo

chemistry
how can i make 30 ml, 0.227 mol of hydroiodic acid from 50 ml hydroiodic acid of 57 wt% in water?
Monday, January 30, 2017 by Smit

chemistry
commercially available concentrated Hydrochloric acid is 37.0% w/w Hcl.its density is 1.18g/ml.using this information calculate (a)the molarity of concentrated Hcl,and (b)the mass and volume (in ml)of solution containing 0.315 mol of Hcl?
Monday, January 30, 2017 by twiza

chemistry
How many grams of MgO are produced during an enthalpy change of -199 kJ? 2 Mg(s) + O2(g) → 2 MgO(s) ΔH = -1204 kJ
Monday, January 30, 2017 by chloe

Chemistry
(1)Make 500 ML of 4N H3PO4. How many grams will be needed? (2) In a titration procedure, 20mL of 2N solution were required to titrate 5mL of an unknown solution. What is the normality of the solution? (3) How much of a 0.01M can be made from 20mL of 6M HCl? (4)How many grams ...
Monday, January 30, 2017 by Nelson

Chemistry
The human body “burns” glucose (C6H12O6) for energy. a. Write a balanced chemical reaction for the complete combustion of glucose to CO2(g) and H2O(l) such that the stoichiometric coefficient for glucose is 1. b. When 1.00 g of glucose are completely burned at 298.15 K and...
Monday, January 30, 2017 by Jim

Chemistry
Calculate the Delta Hf of the OH- ion given that the Delta Hf (H2O) = -285.8 kJ mol-1.
Monday, January 30, 2017 by Jim

Chemistry
How much heat (in kilojoules) is required to warm 11.0 g of ice, initially at -14.0 ∘C, to steam at 112 ∘C? The heat capacity of ice is 2.09 Jg−1∘C−1 and that of steam is 2.01 Jg−1∘C−1.
Monday, January 30, 2017 by Julia

chemistry
Explain the first ionization energy of lithium is greater than that of sodium
Monday, January 30, 2017 by donald

chemistry
How many unpaired electrons for cr3+
Monday, January 30, 2017 by donald

chemistry
A solution of 25.0mL of 0.10mol/L hydroiodic acid is titrated with 0.10mol/L ammonia.Determine the pH at equivalence.
Sunday, January 29, 2017 by rana

Chemistry 112
Can someone please explain to me how to calculate reaction order with respect to something? I've read this in my textbook, and I watched videos on YouTube, but I still don't understand. Please help.
Sunday, January 29, 2017 by Aiyana

Chemistry
How many liters would 1.000g of helium gas occupy at STP?
Sunday, January 29, 2017 by Vincent

chemistry
Calculate ∆S universe for the process H2O (s) → H2O (l) given that ∆Hfusion = 6.02 kJ/mol and ∆S system = 22.1 J/K mol . Remember that ∆S surrounding = -∆Hsystem / T. a) -20oC b) 0oC c) 20oC
Sunday, January 29, 2017 by Mi

Chemistry 112
Can rate of law be a decimal??
Sunday, January 29, 2017 by Aiyana

organic chemistry
The constants for Antoine’s equation for TCE (based on log10 and o C) are: A= 6.5183, B = 1018.6 and C = 192.7. If a container (negligible volume) is placed in a sealed room 1000 m3 at 30 oC, how many grams of TCE will evaporate upon reaching equilibrium with the liquid and ...
Sunday, January 29, 2017 by Lauren

chemistry
From each pair of substances below, choose the one with the higher molar So, at 298 K a) Hg (s), Hg (l) d) C2H6 (g), C2H4 (g) b) HI (g), HCl (g) e) H2 (1 atm), H2 (2 atm), 1 mol at 298 K c) NH3 (g), Ne (g) f) NaCl(s), NaCl (aq)
Sunday, January 29, 2017 by Jaline

Chemistry
Compunds formed by NH4+ and NO3-
Sunday, January 29, 2017 by Carlilah

Chemistry
The vapor pressure of pure water at 30C is 31.8Torr. What is the vapor pressure of a solution of NaCl dissolved in water when the mole fraction of NaCl is 0.111? I am wondering if this would be correct. 0.11*31.8= 3.5 Torr Is there another way to solve this and get the same ...
Sunday, January 29, 2017 by Christopher

chemistry
a pipet can be calibrated. we expected the volume to be 25.00ml, but the actual volume was significantly less. if you had measured the density of an unknown with this pipet and assumed that v=25.00ml, your result would not be correct. would it be too high or too low? Explain
Sunday, January 29, 2017 by mary

Chemistry
Given Ka values of 5.76×10^-10 & 4.8×10^-10, for NH4+ anf HCN.what is the equilibrium constant for following reaction? NH4+ + CN- >< NH3 + HCN
Sunday, January 29, 2017 by Rishi

chemistry
What is the half-life of an isotope that decays to 50% of its original activity in 55.6 hours?
Saturday, January 28, 2017 by Anonymous

Chemistry
Say there is a diluted solution and we need to find the final concentration of it, using the equation M1V1 = M2V2. Does this method change, if the compound (concentration that we're trying to find), is in a solution that has already reacted with another compound? Ex: CaCO3 + ...
Saturday, January 28, 2017 by Naomi

Chemistry
In the aqueous solution of H2SO4 its mole fraction is 0.2 then closest value of molality or solution is a)13.9 b)9.8 c)10.2 d)11.2
Saturday, January 28, 2017 by Aditya

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