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March 27, 2017

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Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
calculate the number of molecules in 6.4g of so2. (b) 1.5 moles of hydrogen chloride
Sunday, February 19, 2017 by obot

college chemistry
How many grams of NaCN are needed to react with 50.0 g of MgCl2?
Saturday, February 18, 2017 by Al

Chemistry
Writing balanced chemical reaction of K2CO3 (s) and HCl (aq) ???
Saturday, February 18, 2017 by Hashini

science, chemistry
Lead metal is added to 0.150 M Cr3+(aq). Pb(s)+2Cr3+(aq)⇌Pb2+(aq)+2Cr2+(aq). KC=3.2×10−10 What is [Pb2+] when equilibrium is established in the reaction? What is [Cr2+] when equilibrium is established in the reaction? What is [Cr3+] when equilibrium is established in the ...
Friday, February 17, 2017 by Sara

Chemistry
The number of calories needed to raise the temperature of 5.0g of water from 25C to 55C
Friday, February 17, 2017 by Daph

Chemistry
How Would You Classify The Oxides Of period3A Elemet?
Friday, February 17, 2017 by Isaac

COLLEGE CHEMISTRY
write the net ionic equation (including phases) that corresponds to zn(no3)2 + Na2CO3--->ZnCO3+2NaNO3.
Friday, February 17, 2017 by Alex

Chemistry AP
Determine the value of x in al2(so4)3 . xh2o when 4 grams of aluminum sulfate hydrate was heated and 3.5 grams remain. (show working please)
Friday, February 17, 2017 by Roger

chemistry
Q: Find pH of 0.2 M of CH3COONa + 0.1M of CH3COOH?
Friday, February 17, 2017 by Basharat

Chemistry
Find the number of miles of calcium chloride 0.44g
Thursday, February 16, 2017 by Cynthia

Chemistry
How many liters of CO2 will be formed from 200. grams of this sugar at STP? C6H12O6--2C2H6O+2CO2
Thursday, February 16, 2017 by William

chemistry
How much energy is required to increase the temperature of 755 g of iron from 10 ̊C to (40,679 J)?
Thursday, February 16, 2017 by monica

chemistry
Hi, I'm doing a post-lab report and I have no idea how to solve this question. It asks which of the following molecules would be useful in quenching benzophenone photoreduction. it then lists oxygen (s1 = 22kcal/mol), 9,10-diphenylanthracene (t1=42 kcal/mol), trans-1,3-...
Thursday, February 16, 2017 by Alexa

Chemistry
Iron pyrite (FeS2) is the form in which much of the sulfur exists in coal. In the combustion of coal, oxygen reacts with iron pyrite to produce iron(III) oxide and sulfur dioxide, which is a major source of air pollution and a substantial contributor to acid rain. What mass of...
Thursday, February 16, 2017 by Danana

Chemistry
Air bags in cars are inflated by the sudden decomposition of sodium azide (NaN3) by the following reaction. 2 NaN3(s) −→ 3 N2(g) + 2 Na(s) What volume of N2 gas, measured at 1.30 atm and 88.0◦C, would be produced by the reaction of 65.0 g of NaN3? Answer in units of L.
Thursday, February 16, 2017 by Danana

Chemistry
If one wanted to a make a 500.0 mL of 4.5 x 10-6M solution of this red dye, how many grams would they need to weigh out? The molar mass of the dye is 492 g/mol. SHOW WORK.
Thursday, February 16, 2017 by Steven

Chemistry
Write “yes” or “no” below if the chemical equation is balanced or not. 1. 2H2 + O2 ---> 2H2O 2. S8 + 12O2 ---> 8SO3 3. HgO ---> Hg + O2 4. Zn + HCl ---> ZnCl2 + H2 5. 2Na + 2H2O ---> 2NaOH + H2 6. 2Al + 3FeO ---> Al2O3 + 3Fe 7. 4Si2H3 + 11O2 ---> ...
Thursday, February 16, 2017 by Bro...?...

Chemistry
Give the oxidation state for the metal ion in each of the following compounds, respectively: K2O,CaO,TiO2,V2O5
Thursday, February 16, 2017 by Diana

math statistic
One of your friends knows that you are taking Advanced Placement Statistics and asks for your help wither Chemistry lab report. She has come up with five measurements of the melting point of a compound: 122.4, 121.8, 122.0, 123.0, and 122.3 degrees Celsius. a. The lab manual ...
Thursday, February 16, 2017 by rhinechilde

Chemistry
Which of the following statements cannot be assumed for the vapourization of a liquid? A)Enthalpy is positive B)Entropy is postive C)Temperature (in degrees Celcius) is positive D)They are all true
Thursday, February 16, 2017 by Sarah

Chemistry
Is the following a properly written thermochemical equation? 2C8H18 + 25O2 → 16CO2 + 18H2O, ΔH = –5,471 kJ/mol No, the equation does not list the enthalpy of reaction. Yes, the equation is correct. No, the equation does not list the states of each substance. No, the ...
Wednesday, February 15, 2017 by AM

Chemistry
In the following chemical reaction between H2 and Cl2 to produce HCl, what is the mass of HCl produced with 0.35g of H2 completely reacts with 12.42g of Cl2?
Wednesday, February 15, 2017 by Anonymous

chemistry
magnesium react with hydrochloric acid,what is the volume of hydrogen produced at r.t.p when 0.12g of magnesium ribbon react?
Wednesday, February 15, 2017 by BLESSING

chemistry
If 25 g of NH4Cl is dissolved at 80C, how many additional grams would be needed to make the solution saturated?
Tuesday, February 14, 2017 by Veronica

chemistry
How many grams of O2(g) are needed to completely burn 17.3 g of C3H8(g)?
Tuesday, February 14, 2017 by alex

chemistry
How many grams of NH4Cl will dissolve at 50 degrees C?
Tuesday, February 14, 2017 by demi

Science(chemistry)
Some students believe that teachers are full of hot air. If I inhale 2.2 litres of gas at a temperature of 18 degree Celsius and it heats to a temperature of 38 degree Celsius in my lungs,what is the new volume of the gas?
Tuesday, February 14, 2017 by Arthur

Chemistry
Given that the battery produces a current of 2.5A that passes through molten zinc chloride for 3 minutes what charge would be dissipated through the electrolyte
Tuesday, February 14, 2017 by Michelle

Chemistry
Express the absolute value of the partial charges as a decimal fraction of the elementary charge for CH. The bond length, is 131.1 pm, and the Dipole Moment, D is 1.46
Tuesday, February 14, 2017 by Nicole

Chemistry
Express the absolute value of the partial charges as a decimal fraction of the elementary charge for OH.
Tuesday, February 14, 2017 by Nicole

Chemistry
What mass of sucrose should be added to 75 gram of water to raise the boiling point about 100.35°C.What mass of sucrose is required to produce the solution of this molality?
Tuesday, February 14, 2017 by Mehreen

chemistry
queous solution of sodium phosphate (Na3PO4). Adding which compound to the solution will cause a phosphate compound to precipitate?
Tuesday, February 14, 2017 by Anonymous

Chemistry
When heated, KClO3 decomposes into KCl and O2. If this reaction produced 79.9 g of KCl, how much O2 was produced (in grams)?
Monday, February 13, 2017 by Nicole

chemistry
Complete combustion of 4.20 g of a hydrocarbon produced 13.4 g of CO2 and 4.81 g of H2O. What is the empirical formula for the hydrocarbon?
Monday, February 13, 2017 by Alex

Chemistry
If you begin with 34.4 grams of ammonia how many grams of hydrogen and nitrogen can you produce in a decomposition reaction
Monday, February 13, 2017 by Kyla

Chemistry
Element X has a face-centered cubic unit cell structure. If the density of the element is measured to be 12.4 g/cm^3, what is the atomic radius of X? units are in pm (picometers) MM: 102.9055 g/mol I have done this 4 different times and came up with the same answer - 381pm, ...
Monday, February 13, 2017 by Amanda L

Chemistry
Complete and balance each of the following molecular reactions. Indicate the phase of each species. If no reaction occurs, write N.R. A) ____ Na2CO3 (aq) + ___ Mg (NO3)2 (aq) --> B)____ K2SO4(aq) + ___ Fe(CH3CO2)2 (aq) --> C)___ AlCl3 (aq) +____ K2S (aq) Please help and ...
Monday, February 13, 2017 by Emily

Chemistry
A reaction requires 22.4 L of gas at STP. You have 30.5 L of gas at 101.5 kPa and 373 K. Which of the following statements is true? (Use the ideal gas law: PV = nRT where R = 8.31 L-kPa/mol-K.) You will have excess gas for the reaction. You will have enough gas for the ...
Monday, February 13, 2017 by Michael

chemistry
determine the mass of carbon4oxide produced from burning 104g of ethyne
Monday, February 13, 2017 by Hafsat

chemistry
If there are 2.871mol of gas present at a temperature of 200.0K and a pressure of 1.009atm, what would the volume be?
Monday, February 13, 2017 by jennifer

Chemistry
what is the concentration of I- before the reaction when 35 ml of 0.23M KI is mixed with 15 ml of 0.15M Fe3+ 2I- + 2Fe3+ --> 2Fe2+ + I2
Monday, February 13, 2017 by Farh

chemistry
How can we separate a mixture of iron filings and sodium chloride
Monday, February 13, 2017 by T.j

Chemistry
Trimix 10/50 is a gas mixture that contains 10% oxygen and 50% helium, ant the rest is nitrogen. If a tank of Trimix 10/50 has a total pressure of 2.07 x 10 4 kPa, then what is the partial pressure of helium?
Monday, February 13, 2017 by kathy

chemistry (ap)
using the measured value of the extinction coefficient for CV ( extinction coefficient = 87,000 M−1 cm−1 ) calculate the [CV] for and abs of 0.9562 (CV stands for Crystal Violet)
Monday, February 13, 2017 by Jamera

Chemistry
which compound shows small change in solubility from 0°C to 100°C?
Monday, February 13, 2017 by Rayan

Chemistry (ap)
using the measured value of the extinction coefficient for CV ( extinction coefficient = 87,000 M−1 cm−1 ) calculate the [CV] for and abs of 0.9562
Monday, February 13, 2017 by Jamera

Chemistry
While you are doing heavy work, your heart pumps up to 25.0 L of blood per minute. Your muscles get about 80% by volume of your blood under these conditions. What volume of blood in quarts is pumped through your muscles in 107 minutes of work that causes your heart to pump 20....
Sunday, February 12, 2017 by Daneila

Chemistry
What volume of oxygen gas at STP would be needed for the complete combustion of 39.0 grams of octane ?
Sunday, February 12, 2017 by Ned

Chemistry
What volume of 12.1 HCL (aq) is needed to prepare 250.0 mL of 1.00 M HCL (aq).
Sunday, February 12, 2017 by Eddie

Chemistry
You are supposed to mix 250 mL of a 0.1 M solution of Pb(NO3)2 solution. You would need to mix ______ g of Pb(NO3)2 with enough water to make 250 mL of solution.
Sunday, February 12, 2017 by Kelly

chemistry
When silver nitrate reacts with barium chloride, silver chloride and barium nitrate are formed. How many grams of silver chloride are formed when 8.0 g of silver nitrate reacts with 15.0 g of barium chloride? Please explain how to do this. I honestly do not know.
Sunday, February 12, 2017 by china

Chemistry
A 14.9g of lead at 92.5C is dropped into a calorimeter with 165g of water at 20.0C. The final temperature of the system is 20.2C. What is the lead's specific heat? -Could I get help setting this up? I'm not sure how I'm supposed to set it up.
Sunday, February 12, 2017 by Nav

Chemistry 2
The molar heat of solution of ammonia is −30.50 kJ/mol. What happens to the temperature of water when ammonia is added to it? I simply don't know how to answer this and wouldn't ask otherwise. I would be very grateful for assistance.
Sunday, February 12, 2017 by Eric

Chemistry
You add 3.5 L of an HCl solution of unknown concentration to 2.0 L of 0.5 M HCl and 4.5 L of water. The final concentration of HCl was 1.5 M. What was the unknown concentration of the initial HCl solution?
Sunday, February 12, 2017 by Laura

chemistry
A stock solution of HNO3 is prepared and found to contain 11.1 M of HNO3. If 25.0 mL of the stock solution is diluted to a final volume of 0.500 L, the concentration of the diluted solution is ________ M.
Sunday, February 12, 2017 by chanel

Chemistry
Consider an alloy that is 14.1% copper by mass in tin. Copper makes up what percentage of the atoms in this sample?
Sunday, February 12, 2017 by Seth

Chemistry
what is the molarity of the following solution? 13.8g of potassium trioxocarbonate (IV) in 200cm^3 of solution
Sunday, February 12, 2017 by Hayzed

chemistry
10.5g of potassium trioxonitrate(v) salt saturated 5g of solvent at 15°c. Calculate the solubility of potassium trioxonitrate(v) salt at that same temperature in: a)g/100g of solvents b)moles per dm^-3
Sunday, February 12, 2017 by Isaac

chemistry
one of the ingredients in detergent making, lauryl alcohol is extracted from coconut oil. A 5.00 g of this substance is added to 100 g of benzene and the solution boils at 80.78° C. what is the molar mass of lauryl alcohol?
Sunday, February 12, 2017 by elmer iscal

chemistry
if 6.0g of carbon is heated in air, the mass of the product obtained could be either 22.0g or 14.0g depending on the amount of air present. with what law would this be in accordance? (C=12, O=16)
Sunday, February 12, 2017 by Nana Khadija

Chemistry
If you wanted to create a equimolar buffer using 1.0 mol of NaHS in 1.0L of water what acid would you need to add? how many moles of that acid do you need to add?
Saturday, February 11, 2017 by Jake

Chemistry
Calculate the expected freezing point of a solution of 0.579 g pelargonic acid in 4.225 g of lauric acid, if the melting point of pure lauric acid was measured to be 43.20*C. (MM pelargonic acid = 158.2 g/mol; MM laruic acid = 200.32 g/mol). Kf for lauric acid is 3.90*C/Mc; ...
Saturday, February 11, 2017 by Amanda

chemistry please help
what is wrong with these names?provide the correct name for each. i.2-Dimethylpentane {4] ii.2-Ethylpentane {4} iii.5,5-Dimethyl-3-ethylhexane {4]
Saturday, February 11, 2017 by sophie

Chemistry
Element X has a face-centered cubic unit cell structure. If the density of the element is measured to be 12.4 g/cm^3, what is the atomic radius of X? units are in pm (picometers) I can't seem to find how to get the atomic radius with only the density given for an unknown ...
Saturday, February 11, 2017 by Amanda

Chemistry
338 grams of the organic liquid hexane is poured into a tall cylindrical container that has a base with radius 2.91 cm. Given that hexane has a density of 0.66 g/mL, what is the distance (in cm) between the bottom of the cylinder and the surface of the liquid?
Saturday, February 11, 2017 by Daneila

Organic Chemistry
The compounds below are contained in a mixed sample. Rank the compounds in order of elitism if separated using a silica gel column rank them from what elutes first to what elutes last. Benzoic acid, 1,3-dichlorobenzene, tert-butylcyclohexane, and 2-pentanol So far from first ...
Friday, February 10, 2017 by Arianna

Chemistry
The heat of combustion of liquid hexane (C6H14) to carbon dioxide and liquid water at 298 K is -4215 kJmol−1 . Find ΔrU of the reaction.
Friday, February 10, 2017 by someone

Chemistry
What is the molality of a solution of water and KCl if the boiling point of the solution is 103.07°C? (K subscript b equals 0.512 degrees C/m solution; KCl is an ionic compound right parenthesis A: .300 B: .600 C: 3.00 D: 6.00 I'm really confused as to how to solve this, and ...
Friday, February 10, 2017 by Emily

chemistry
The density of a certain type of plastic is 0.89 g/cm3. If a sheet of this plastic is 10.0 m long, 1.0 m wide, and 1.0 cm thick, what is its mass?
Friday, February 10, 2017 by tas

Chemistry
Hello, I just would like to know the different types of formulas for moles... Example: Molecular, empirical, etc. I would like to know them for an upcoming test. Just to refresh my memory
Friday, February 10, 2017 by Lusa

Chemistry
You start with 2.5L of a KNO3 stock solution and wish to prepare 10.0 L of 1.5 M KNO3. What percentage (m/v) would the potassium nitrate stock solution need to be if you were to use it all? (MW of KNO3: 101g/mole)
Thursday, February 9, 2017 by sarah

Chemistry.HELP (IONS)
Determne the boiling point of 16.3g of calcium chloride dissolved in 250. g water. My work: 16.3 g CaCl2 *(1 mole CaCl2/110.984 g Cacl2)= 0.147 mol CaCl2 M= 0.147/0.250kg =0.588 mCaCl2 ... From here, How do you find out how many ions CaCl2 has. Calcium has a 2+ charge and Cl ...
Thursday, February 9, 2017 by Julia

Chemistry
"How many grams of the precipitate will form if 25.5 mL of 4.5 M solution of lead (II) nitrate is allowed to react with 35.5 mL of 3.0 M solution of potassium chloride? What is the concentration of the excess reactant after the reaction has reached completion?" I got that the ...
Thursday, February 9, 2017 by cj

Math/Chemistry
How to rearrange the given equation for A: ln (Ao/A) = k*t
Thursday, February 9, 2017 by Kara

Math/Chemistry
How to rearrange the given equation for Ao: ln (Ao/A) = k*t
Thursday, February 9, 2017 by Kara

Chemistry
The reaction of nitrogen dioxide with fluorine generates nitryl fluoride: 2NO2(g) + F2(g) --> 2NO2F(g) To determine the rate law for this reaction, a chemist performed several initial-rate experiments using different initial concentration, with the details tabulated below. ...
Thursday, February 9, 2017 by Lily

Chemistry
The following is a Limiting Reactant problem: Magnesium nitride is formed in the reaction of magnesium metal with nitrogen gas in this reaction: 3 Mg(s) + N2(g) -> Mg3N2(s) How many grams of product are formed from 2.0 mol of N2 (g) and 8.0 mol of Mg(s)?
Thursday, February 9, 2017 by Ari

chemistry
calculate the pH of 0.1M NH4NO3
Thursday, February 9, 2017 by augustus

Analytical Chemistry
1. If the unknown solid were not dried before analysis, would the calculated percent of KHP be too high or too low? Explain
Thursday, February 9, 2017 by Mia

Chemistry
What mass of salt(NaCl)should you add to 1.20 L of water in an ice cream maker to make a solution that freezes at -10.4∘C?
Thursday, February 9, 2017 by Anna

Chemistry
The density of cesium is 1870 kg/m3 and the cell volume is 2.23 x 10-22 mL. Determine the number of atoms in the unit cell. Note: the number of atoms in a unit cell is a whole number.
Wednesday, February 8, 2017 by Joe Zheng

Chemistry
What mass of salt(NaCl)should you add to 1.20 L of water in an ice cream maker to make a solution that freezes at -10.4∘C?
Wednesday, February 8, 2017 by Anna

chemistry
If 25.4 g of water initially at 20.0 C absorbs 115 cal heat what is final temp?
Wednesday, February 8, 2017 by Anna Baker

chemistry
describe how you prepare a 250cm3 of 0.5M solution Na2C03.indicate the variouse laboratory apparatus you will use
Wednesday, February 8, 2017 by Dorcas

chemistry
describe how you prepare a 250cm3 of 0.5M solution Na2C03.indicate the various laboratory apparatus you will use
Wednesday, February 8, 2017 by Dorcas

chemistry
what is the theoretical yield in grams of MgO if 2.54g Mg metal reacts with excess O2
Wednesday, February 8, 2017 by naty

chemistry
2CH3OH + 3O2-> 2CO2 + 4 H2O wHAT IS THE AMOUNT OF OXYGEN IS REQUIRED TO COMPLETRLY BURN 5 MOL OF METHANOL?
Wednesday, February 8, 2017 by melissa

Chemistry
The element Sc has hcp packing with a hexagonal unit cell. The density of Sc is 3000 kg/m3. Calculate the volume (L) of the unit cell of Sc. Sc Molar Mass =44.956 It is hcp, so it has 2 atoms/unit cell. I would appreciate any help with this problem! Thank you in advance!
Wednesday, February 8, 2017 by Jenny Selby

Chemistry
The element rubidium has bcc packing with a body-centered cubic unit cell. The density of Rb is 1530 kg/m3. Calculate the volume (L) of the unit cell of rubidium. Molar mass of Rb=85.468. Since it is bcc, it would have 2 atoms/unit cell. Can you please help me solve this? ...
Wednesday, February 8, 2017 by Sidney Ngo

Chemistry
The density of iridium is 22400 kg/m3 and the cell volume is 5.66 x 10-23 cm3. Determine the number of atoms in the unit cell. Note: the number of atoms in a unit cell is a whole number. The molar mass of iridium is 192.22. I know that this can either be a bcc, cap, or hcp ...
Wednesday, February 8, 2017 by Sidney Ngo

Chemistry
a. If 5.57 g of glucose are produced through photosynthesis, what is the minimum number of moles of carbon dioxide and of water that were used? b. If the 5.57 g of glucose is an 80.2% yield, and assuming that carbon dioxide was the limiting reagent, how many moles of carbon ...
Wednesday, February 8, 2017 by Seida

Chemistry
Aluminum and oxygen react to form aluminum oxide. 4 Al + 3 O2 2 Al2O3 a. What is the limiting reactant if 30.7 g Al are reacted with 38.3 g of O2? b. What is the theoretical yield of Al2O3, in grams? c. If 35.3 g of Al2O3 are obtained, what is the percent yield?
Wednesday, February 8, 2017 by Seida

Chemistry
Consider the following reaction. 2KClO3(s) → 2KCl(s) + 3O2(g) a.) How many grams of KCl are produced from the complete reaction of 12.5 mol of KClO3? b.) How many grams of KCl are produced from the complete reaction of 38.4 g of KClO3? Please explain how to solve for the ...
Wednesday, February 8, 2017 by Seida

Chemistry
When nitrogen dioxide is bubbled through a solution of potassium permanganate, the solution turns colorless. Which of the following statements is true? Question 3 options: 1) The test reveals that nitrogen dioxide is a colored gas. 2) The test reveals that nitrogen dioxide is ...
Wednesday, February 8, 2017 by Carley B.

chemistry
An aqueous solution containing bromothymol blue is used to identify the chemical properties of thionyl chloride gas. When the gas is bubbled through the bromothymol blue solution color changes from blue to yellow we could say that the gas ____________________. Question 4 ...
Wednesday, February 8, 2017 by Carley B.

Chemistry
The sodium sulfite-acid solution should be disposed of by ____________________. Answers Options: 1) washing down the drain with large amounts of water. 2) washing out with diluted sodium bicarbonate for sink disposal. 3) neutralizing the solution with sodium bicarbonate before...
Wednesday, February 8, 2017 by Carley B.

math
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 and 18 study biology but not chemistry.Determine the number of students who study =Art only =Chemistry only
Wednesday, February 8, 2017 by Nana Adwoa

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 Sarah

Chemistry
Assuming that the unknown acid sample in question 1 had a mass of 0.177 g, what is the molar mass of the unknown acid?
Wednesday, February 8, 2017 by Erin

Chemistry
Suppose that 16.41 mL of 0.0512 M NaOH were required to titrate a sample of unknown acid. How many moles of NaOH were used?
Wednesday, February 8, 2017 by Erin

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