Sunday
August 28, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Bio physics chemistry pre medical
Vitamin a has a molecular formula c 20 h 30 o. How much no of molecules will vitamin a contian in 500mg capsule? ? Plz tell me now tomorrow is my test .I will be very grateful of u. .
Sunday, August 28, 2016 by Hania

Bio physics chemistry pre medical
Methane react with steam to form h2 and co. . what volume of h2 can be obtained from 100cmcube of methane at the standard temperature and pressure? ?
Sunday, August 28, 2016 by Hania

Chemistry
if 12.8g of NaCl is added to 243.2 mL of water (density (1.00g/mL)). the volume occupied by the solution is 250.0 mL. Calculate the density of the salt water.
Sunday, August 28, 2016 by Anonymous

Chemistry
The weight of kclo3 which thermal decomposition o2 gas sufficient for the combustion of 1.12 litres of ethlene gas at STPis
Sunday, August 28, 2016 by Anonymous

Chemistry
One volume of a hydrocarbon require 3 volume of oxygen for complete combustion then formula for hydrocarbon
Sunday, August 28, 2016 by Anonymous

Chemistry
How many electrons involved in the reduction of one mole of Al2o3 to aluminium metal
Sunday, August 28, 2016 by Anonymous

Chemistry
How many moles of potassium permanganate is necessary to oxidise o.5 moles of soadium sulphate in acid medium
Saturday, August 27, 2016 by Anonymous

Chemistry
A flask of known volume was filled with air to a pressure of 3.6atm. This flask was then attached to an evacuated flask of known volume and the air was allowed to expand into the flask. The final pressure of the air (in both flasks) was 2.7atm and the volume of the second ...
Saturday, August 27, 2016 by Scott

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...
Saturday, August 27, 2016 by Damon

Chemistry
Hello, please I need help with this excersice of chemical equilibrum. I really don't get what "1:6" means and how can I use that proportion". The excercise says: "0,014" moles of HCl are dissolved in water in a proportion of 1:6 (1 mole of HCl per ...
Saturday, August 27, 2016 by Nelson

Chemistry
Why is the heat of neutralization between HCL and NaOH is higher than CH3COOH and NaOH
Saturday, August 27, 2016 by Christian Dadzie

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...
Friday, August 26, 2016 by Damon

Chemistry
Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...
Friday, August 26, 2016 by anon

chemistry
how to differenciate potassium carbonate from calcium carbonate in terms of deliquiscence,hygroscopy and efflorescence
Friday, August 26, 2016 by asa

chemistry
how to differenciate potassium carbonate from calcium carbonate in terms of deliquiscence,hygroscopy and efflorescence
Friday, August 26, 2016 by asa

Chemistry
How Many Atoms Are There In 10grams Of Carbon
Thursday, August 25, 2016 by Seyi

Chemistry
How Many Atoms Are There In 10grams Of Carbon And How Many Molecules Are There In 10grams Of Calcium Carbonate
Thursday, August 25, 2016 by Mickid

chemistry
A solution is made by mixing 25 mL of .35 M LiOH with 15.5 mL of .2225 M NH3. Kb=1.8x10^-5 for NH3 Calculate the pH for the solution.
Thursday, August 25, 2016 by sara

chemistry
2.2. Billions of kilograms of urea, are produced annually for use as a fertilizer. The reaction used is given below. NH3(g) + CO2(g) → CO(NH2)2(s) + H2O(l) The typical starting reaction mixture has a 3:1 mole ratio of NH3 to CO2. If 47.7 g urea forms per mole of that ...
Wednesday, August 24, 2016 by mandla

Chemistry
Which of the following would be the best to measure 18mL of acohol accurately and precisely
Wednesday, August 24, 2016 by Miekyela

Chemistry
One hundred grams of mixture of NaSO4 – 10H2O and Na2CO3 – 10H2O are heated to drive off water of hydration. The final weight of the mixed salts is 39.6g. What is the ration of moles Na2CO3 to moles Na2SO4 in the original hydrated salts?
Wednesday, August 24, 2016 by Neshen

Chemistry
25.0 mL of an H3BO3 solution were titrated with 29.15 mL of a 0.205 M LiOH solution to reach the equivalence point. what is the molarity of the H3BO3 solution?
Tuesday, August 23, 2016 by Kat

chemistry
how much NAOH must be added to 500ml acetic acid 0.5Mol to give ph 0.5
Tuesday, August 23, 2016 by elie king

Chemistry
A 2.80-g sample of haematite ore containing Fe3+ ions was dissolved in a concentrated acid and the solution was diluted to 250 mL. A 25.0 mL aliquot was reduced with Sn2+ to form a solution of Fe2+ ions. This solution of Fe2+ ions required26.4mL of a 0.0200 M K2Cr2O7 solution ...
Tuesday, August 23, 2016 by Luke

chemistry
how to balance combustion of 5% by volume in air. 1. 0.05 CH4 + ( )(0.21 O2 + 0.79 N2) 2. ( )CH4 + O2 + 0.376 N2
Monday, August 22, 2016 by skrishna

Chemistry
How many moles of chloride ions are in 0.04dm^3 of 0.45M calcium chloride CaCl2
Monday, August 22, 2016 by Florence

Chemistry
What mass of glucose (c6h12o6)is produced from 18g of co2 when it reacts with water molecule? 6Co2+6H2o→c6h12o6+Co2
Monday, August 22, 2016 by Nasir khan

Chemistry
What is the mole fraction of ethanol, C2H5OH, in an aqueous solution that is 50.0% ethanol by mass?
Monday, August 22, 2016 by Devon

chemistry
which of following show cistrans isomerism?
Monday, August 22, 2016 by ali

chemistry
The amount of sulphuric acid (in gm) required to neutralise 10L of ammonia at STP is
Monday, August 22, 2016 by Hamza

Chemistry
There are three naturally occurring isotopes of the hypothetical element hilarium 41Hi, 42Hi, and 44Hi. The percentages of these isotopes are the following: Hilarium Natural Isotopes Abundance 41Hi 18.7% 42Hi 43.6% 44Hi 37.7% You can assume that the atomic masses are exactly ...
Monday, August 22, 2016 by anonymous

chemistry
When 25 mL of C2H5OH (density 0.80 g.cm-3) is dissolved in water to prepare a 250 mL solution, the density of the solution was found to be 0.950 g.cm-3. Calculate a. Molarity of pure ethanol; b. Molarity of ethanol in the final solution; c. Volume of the final solution which ...
Monday, August 22, 2016 by avni

chemistry
What is the equilibrium expression for the following acid dissociation reaction? CH3COOH + H2O CH3COO- + H3O+ A. [CH3COO-][H3O+]/[CH3COOH][H3O] B. [CH3COOH][H2O]/[CH3COO-][H3O+] C. [CH3COOH]/[CH3COO-][H3O-] D. [CH3COO-][H3O+]/[CH3COOH]
Monday, August 22, 2016 by jessie

chemistry
A reaction has an equilibrium constant very much less than 1. Will the reaction proceed spontaneously? A. Yes, because products are favored and deltaG° < 0. B. Yes, because reactants are favored and deltaG° > 0. C. No, because reactants are favored and deltaG°...
Monday, August 22, 2016 by jessie

chemistry
If the equilibrium constant is much less than 1, how can you tell where the equilibrium lies? A. Reactants are in the numerator of the equilibrium expression, so equilibrium lies toward the reactants. B. Products are in the numerator of the equilibrium expression, so ...
Monday, August 22, 2016 by jessie

chemistry
What information does an equilibrium constant give about a reaction? A. It tells how long it takes the reaction to reach equilibrium. B. It tells how much energy is required for the reaction to happen. C. It tells what the rate constant of the reaction is at equilibrium. D. It...
Monday, August 22, 2016 by jessie

Chemistry
determine the ph of 5 grams KNO3 that is dissolved in 100ml water.KNO3 is produced by mixing .2M KOH and 0.2M HNO3...please help me...pls..
Sunday, August 21, 2016 by Jonalyn

Chemistry
determine the ph of 5 grams KNO3 that is dissolved in 100ml water.KNO3 is produced by mixing .2M KOH and 0.2M HNO3...please help me...
Sunday, August 21, 2016 by Jonalyn

chemistry
A piece of zinc was added to 1000cm³ of 0.2m hydrochloric acid. After effervescence head stopped, 30cm³ of the resulting solution required 22cm³ of 0.08m sodium trioxocarbonate (iv) solution for complete neutralization, calculate the mass of zinc added.
Sunday, August 21, 2016 by victor Ilevbare

chemistry
P4 + HNO3 = H3PO4 + NO2 + H20 by partial method balancing
Sunday, August 21, 2016 by Durgesh

chemistry
If your favorite silver jewelry ever tarnishes and you happen to have some aluminum foil on hand, you can actually get rid of some of that tarnish. The tarnish here is actually silver sulfide. If you put the jewelry and aluminum into a dish with enough water to cover them both...
Sunday, August 21, 2016 by student in revolt

Science Chemistry
Calculate the no. of grams of NaOH req. to absorb volume of the CO2 gas produce as Na2CO3
Sunday, August 21, 2016 by Sumee

chemistry
how many moles of fe are present in 30g of rust?
Sunday, August 21, 2016 by ali

Chemistry
How many grams of KCl should be added to 1.5kg of water to lower its freezing point to -7.5°C
Sunday, August 21, 2016 by Anonymous

chemistry
When is there a need to determine G? A. When H > 0 and S < 0 B. When H > 0 and S = 0 C. When H > 0 and S > 0 D. When H = 0 and S < 0
Saturday, August 20, 2016 by sofie

science - chemistry
How can we separate a mixture of iodine, napthalene, chalk dust and saw dust. Write the ans in the form of a flow chart.
Saturday, August 20, 2016 by shaan

chemistry
what is the concentration of na and co3 ions in 0.2M aqueous solution of na2co3
Saturday, August 20, 2016 by Anonymous

chemistry help!!! please!!! DrBob222 I need you!!
How many atoms of carbon are needed to produce 0.45 mol Al? 3C + 2Al2O3 4Al + 3CO2 A. 2.6 × 1026 atoms B. 9.7 × 1024 atoms C. 3.0 × 1022 atoms D. 2.0 × 1023 atoms I'm really very stuck with this question. please help me!!!
Saturday, August 20, 2016 by emma

chemistry help!!! please!!! DrBob222 I need you!!
The G value for formation of gaseous water at 298 K and 1 atm is -278 kJ/mol. What is the nature of the spontaneity of formation of gaseous water at these conditions? A. The reaction is sometimes spontaneous. B. The reaction is spontaneous. C. The reaction may or may not be ...
Saturday, August 20, 2016 by emma

CHEMISTRY
Why is glass considered as a supercooled liquid? answer please!!!
Saturday, August 20, 2016 by A GOODSTUDENT

chemistry
The reaction CHCL3(g)+CL2(g)_CCL4(g)+HCL(g) has the following rate law:Rate =k [CHCL3][CL2].If the concentration of CHCL3 is increased by a factor of five while the concentration of CL2 Is kept the same use a mathematical equation to show the factor by which the rate will ...
Saturday, August 20, 2016 by Felix

CHEMISTRY
why is glass called a supercooled liquid?
Saturday, August 20, 2016 by helpneeded

chemistry
How many atoms of carbon are needed to produce 0.45 mol Al? 3C + 2Al2O3 4Al + 3CO2 A. 2.6 × 1026 atoms B. 9.7 × 1024 atoms C. 3.0 × 1022 atoms D. 2.0 × 1023 atoms
Friday, August 19, 2016 by emma

Chemistry
What is the oxidation state of Cr in K2Cr2O4?
Friday, August 19, 2016 by anon

Chemistry
Aqueous sulfurous acid H2SO3 and aqueous sodium chloride are formed by the reaction of aqueous sodium sulfite Na2SO3 and aqueous hydrochloric acid HCl . Write a balanced chemical equation for this reaction.
Friday, August 19, 2016 by R

chemistry help?!
Which properties result from minimal interactions between molecules in a gas? A. A characteristic geometric shape and limited particle motion B. A random shape, limited particle motion, and inability to be compressed C. A random shape, significant particle motion, and ability ...
Friday, August 19, 2016 by Jessie

chemistry help
How do forces determine the shape of a protein? A. The covalent bonds in the protein determine the shape of the protein. B. The protein folds into complex shapes through intermolecular forces. C. Polar parts of a protein are repelled by water. D. Hydrophobic parts of a protein...
Friday, August 19, 2016 by Jessie

chemistry help?!
Which statement correctly pairs the order of a reaction with the units for the rate constant? A. third order; s/M B. zero order; 1/(M2) C. second order; 1/(M•s) D. first order; 1/M
Friday, August 19, 2016 by Jessie

chemistry help?!
Which of the following terms are present in the rate law? A. The rate constant, the concentration of the reactants, and the order of the reactants B. The rate constant and the concentration of the reactants C. The rate constant and the temperature of the reactants D. The rate ...
Friday, August 19, 2016 by Jessie

chemistry
Which of the following terms are present in the rate law? A. The rate constant, the concentration of the reactants, and the order of the reactants B. The rate constant and the concentration of the reactants C. The rate constant and the temperature of the reactants D. The rate ...
Thursday, August 18, 2016 by Jessie

Chemistry
Which of the following is NOT a characteristic of a strong acid and a strong base? A. Has a [H+] higher than water B. Is corrosive to most metals C. Has a pH at the extreme end of the scale D. Completely dissociates in water
Thursday, August 18, 2016 by Cherry

Science - Chemistry
If the rate law of a chemical reaction is k[NH4+]2[NO2–], what is the order of the reaction? 1. The order of the reaction cannot be determined. 2. 3 3. 1 4. 2
Thursday, August 18, 2016 by Jessie

AP Chemistry help!!!!!
How does the boiling point of ethane (CH3CH3) compare with that of ethanol (CH3CH2OH)? 1. The boiling point of ethane is higher because it has stronger London dispersion forces. 2. The boiling point of ethane is higher because it has stronger dipole-dipole forces. 3. The ...
Thursday, August 18, 2016 by Stephen

Chemistry
Chlorine has two isotopes with mass number 35 and 37. Calculate the relative abundance of the two isotopes accounting for normal atomic mass of 35.5
Thursday, August 18, 2016 by Iyana

chemistry
calculate no of neutrons present in 1*210^25 atoms of oxygen(atomic no of oxygen=8,mass no of oxygen=17
Wednesday, August 17, 2016 by ria

chemistry
2.00g of carbonate reacts with excess hydrobromic acid. Use this balanced equation to fond the theoretical yield. Na2Co3 + 2HBr = CO2 + H2O + 2NaBr
Tuesday, August 16, 2016 by jane

chemistry
A flask contains 0.260 mol of liquid bromine, Br2. Determine the number of bromine molecules present in the flask. Express your answer numerically in molecules.
Tuesday, August 16, 2016 by diana

Chemistry
How do you calculate alkalinity in chemistry? Ex: List the values for total alkalinity for Sample A and Sample B A 104 drops of titrant (5.25mL) 3 drops of C20 H14 O4 B 81 drops of titrant (4.25mL) 3 drops od C20 H14 O4
Monday, August 15, 2016 by anon

Chemistry
Write the net ionic equation for HClO4(aq) + NaOH(aq) --> H2O (l) + NaClO4(aq).
Monday, August 15, 2016 by Heidy

Chemistry
Calculate how many grams of the substance and how many grams of water is in a solution of 400g with a concentration of a 30%
Monday, August 15, 2016 by David

chemistry
25 ml of SHW containing CaCO3 1 g/L consumes 12 ml of EDTA. 25 ml of hard water consumes 8 ml of standard EDTA solution. After boiling the sample, 25 ml of the boiled hard water consumes 6 ml of standard EDTA solution. Calculate the total, permanent and temporary hardness
Monday, August 15, 2016 by priyanka

Chemistry
a 0.1 gm sample requires 20.5 ml B for reaction. the B was standardized by titrating 25 ml of a 0.1M CaCl2 solution, requiring 30 ml B. calculate the percent Al2O3
Monday, August 15, 2016 by 7aji

Chemistry
Determine the cell potential from the following half cells: Pb^o/Pb2+ and ZN^O/Zn2+ whre [Pb2+]=.86Mand [Zn2+]=0.35M Calculate K for this reaction. How long in hours would you have to let it go until you lower the voltage to 95 percent of the E from the Nernst equation at 7.2?
Sunday, August 14, 2016 by Jessica

Chemistry
How many grams of hydrogen chloride acid containing 10% by mass of hydrogen chloride acid would be required to dissolve 13g of zinc
Sunday, August 14, 2016 by Mike

Chemistry
What are the equilibrium concentrations of all the solute species in a 0.95 M solution of hydrogen cyanide, HCN? The Ka value = 6.2 x 10^-10. (a) [H3O+], M; (b) [OH-], M; (c) [HCN], M; (d) What is the pH of the solution? For HCN So far i have calculated the concentration of ...
Sunday, August 14, 2016 by Alice

Chemistry
What volume of 0.123M NaOH contains 0.025 moles of NaOH?
Saturday, August 13, 2016 by Alicia

Chemistry
Calculate the mass of the precipitate formed when 2.27 L of 0.0820 M Ba(OH)2 are mixed with 3.06 L of 0.0664 M Na2SO4.
Saturday, August 13, 2016 by David

Chemistry
Calculate the mass of solid which would be precipitated when 35g of carbon 4 oxide are passed through a solution of calcium hydroxide Show your work
Saturday, August 13, 2016 by Mike

chemistry
?Fe(2+)+?NO3(-)+H(+)==》No+Fe(3+)+​H2O What's the balanced equation?
Saturday, August 13, 2016 by Fred

Analytical Chemistry
how much volume of h2so4 is needed to produce a 0.953 Normality) of h2so4 if the 1 liter solution is 1.14 g/mL in density?
Saturday, August 13, 2016 by Sham

Chemistry
What is the number of molecules in 22. 4 dm^3 of nitrogen gas at STP?
Friday, August 12, 2016 by Vinayak

science(chemistry)
A laboratory instructure gives a sample of Amino-powder to each if four students,1,2,3 and 4,and they weigh the samples.The true value is 8.72g.Their results for three trails are (1),8.72g,8.74g,8.70g (2),8.56g,8.77g,8.83g (3),8.50g,8.48g,8.51g (4),8.41g,8.72g,8.55g (A)...
Friday, August 12, 2016 by mary tembo

Chemistry
How many mL of 0.1 N NaOH are required to react with 100 mEq of H2SO4?
Thursday, August 11, 2016 by David

chemistry
Predict the heat output of the combustion of 1L of octane at 298K. It's mass density is.703 g/cm3
Thursday, August 11, 2016 by deepsikha

Chemistry
The density of silver is 10.5 g/mL, so what is the mass of a 16.3cm^3 piece of silver?
Wednesday, August 10, 2016 by Domo

Chemistry
We add 54g of aluminum to a graduated cylinder containing 50mL of water. What will be the level of water in the cylinder after aluminum has been added?
Wednesday, August 10, 2016 by Domo

Physical Chemistry
A 1.00M sucrose solution freezes at -1.8 degree Celsius. What is the freezing point of 1.00M glucose solution?
Wednesday, August 10, 2016 by Winnie

Chemistry
The weight of a pure sample of KClO3 to be decomposed in order to get 0.96 of O2.
Wednesday, August 10, 2016 by Yathishnv27

chemistry
how many numbers of oxygen molecules are present in 3 litres of CO2 at STP?
Wednesday, August 10, 2016 by sony

chemistry
when heated, kclo3 decomposes into kcl ad 02. 2kclo3--> 2kcl+3o2 if this reaction produced 61.7 g of kcl, how much o2 was produced (in grams)?
Wednesday, August 10, 2016 by AA

ap chemistry
Propane gas and oxygen gas will chemically react via combustion. Write a blanced equation for this change and then use stoichiomety problem solving to determine the number of carbon dioxide molecules that can theoretically form.
Wednesday, August 10, 2016 by anonymous

ap chemistry
Ammonia decompose upon intense heating to produce nitrogen and hydrogen elemental products. Write a balanced equation and then use stoichiometry problem solving to determin the mass of nitrogen product that can form if exactly 25.50g of ammonia is fully decomposed.
Wednesday, August 10, 2016 by anonymous

chemistry
Ammonia decomposes upon heating to produce nitrogen and hydrogen elemental products. Write a balanced equation and then use stoichiometry problem solving to determin the mass of nitrogen product that can form if exactly 25.50 grams of ammonia(NH3) is fully decomposed.
Wednesday, August 10, 2016 by anonymous

chemistry
A major component of gasoline is octane C8H18. When octane is burned in air, it chemically reacts with oxygen gas O2 to produce carbon dioxide CO2 and water H2O. What mass of octane is consumed by the reaction of 8.8g of oxygen gas? Round your answer to 2 significant digits.
Tuesday, August 9, 2016 by Emily

ap chemistry
use dimensional analysis to find how many moles of nitrate ions are in 40.0 mL of a 0.75 M aqueous solution of aluminum nitrate
Tuesday, August 9, 2016 by anonymous

Chemistry
Define normality
Tuesday, August 9, 2016 by Joule eve

Chemistry
If 0.500 mol of each of the following solutes is dissolved in 2.0 L of water, which will cause the greatest increase in the boiling point of the solution? A. KI B. CO2 C. Na2SO4 D. NaCl
Monday, August 8, 2016 by OTP

Chemistry
If 0.500 mol of each of the following solutes is dissolved in 2.0 L of water, which will cause the greatest increase in the boiling point of the solution? A. KI B. CO2 C. Na2SO4 D. NaCl
Monday, August 8, 2016 by SahDuuude

Chemistry
If 152 grams of ethane (C2H6) are reacted with 231 grams of oxygen gas, what is the excess reactant? 2C2H6 + 7O2(g) → 4CO2(g) + 6H2O(g)
Monday, August 8, 2016 by Rohit

chemistry
how many representative particles are there in 5 mole h2o
Sunday, August 7, 2016 by daling

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