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February 14, 2016

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Iron is malleable (able to be hammered into sheets). Is this an intensive physical property, extensive physical property, or a chemical property? Why?
Tuesday, September 8, 2015 by Amy

Chemistry
Below are 2 word equations. For each, identify the type of equation and write a chemical equation with symbols for the word equation. (I have solved the equations but I am not sure what the question means by ``type of equation``) a) Potassium was discovered in 1807 by ...
Tuesday, September 8, 2015 by Anonymous

Chemistry
I'm doing a virtual lab in which I'm trying to separate tin, aluminum, and steel. Does the order in which I heat them at 300 degrees and observe their magnetism matter? The lab says the three are isolated when they are heated to 300 degrees and then placed under a ...
Tuesday, September 8, 2015 by Anonymous

Chemistry
I'm having trouble turning mM to mOsmoles. The equation goes like this: red blood cell are placed into a beaker filled with .5L of a 150mM NACL solution. NACL is non-penetrating solute and will not cross the red blood cell membrane. I have 150mM/0.5L * 2mOsM/100mM But ...
Tuesday, September 8, 2015 by Anna

Chemistry
Hello! I was working on my Chemistry HW about metric conversion. Can you please check to see if my answers are correct? I was having a hard time converting, and I think I finally figured it out. 1 microliter= 0.000001 liters 1 mL= 1,000 microliters 100mL= 0.1 liters 45 ...
Tuesday, September 8, 2015 by Isabella

Organic Chemistry
An unknown carboxylic acid has a boiling point of 100 c at 25 torr. Determine its boiling point at 760 torr. I'm given a list to identify an acid that it correlates with. I'm confused as to how I set this up.
Tuesday, September 8, 2015 by Yoshi

Chemistry
To prepare 500.00 mL of 0.300 M buffer with a pH of 7.4. NaH2PO4/Na2HPO4 How many grams of each should be added to the 500.00mL flask to create this buffer?
Tuesday, September 8, 2015 by Josh

Chemistry
Does aluminum dissolve in acidic and basic solutions?
Tuesday, September 8, 2015 by Anonymous

Chemistry
The distribution coefficient between ether and water for aspirin at room temperature is 3.5. What weight of aspirin would be extracted by a single extraction with 60 ml of water from a solution of 10 grams of aspirin in 100 ml of ether? Calculate the weight of aspirin which ...
Tuesday, September 8, 2015 by Spencer

chemistry
What is the dominant intermolecular force for propionic acid?
Tuesday, September 8, 2015 by nyasha

chemistry
what is molarity of h2so4 solution contaning 9.8g of h2so4 per 500ml?
Tuesday, September 8, 2015 by ahtasham

Organic Chemistry
Consider the crystallization of sulfanilamide from 95% ethyl alcohol. If impure sulfanilamide is dissolved in the minimum amount of 95% ethyl alcohol at 40°C rather than 78°C (the boiling point of ethyl alcohol), how would this affect the percent recovery of pure ...
Tuesday, September 8, 2015 by Lee

Chemistry
A 2.20 g-sample of a compound containing carbon, hydrogen, and oxygen is burned and it produces 4.61 g CO2 and 0.94 g H2O. What is the empirical formula of this compound? (i.e., C2H4O) I found the mass of Carbon (4.61/44g)*(1 mol C/1 mol CO2)=.1047 I found the mass of Hydrogen...
Tuesday, September 8, 2015 by JORDAN

Chemistry 2
When 5.0g of CaCl2 was dissolved in 50 ml of water in a coffee cup calorimeter, the temperature of the solution rose from 22.3C to 30.5C. What is the qsoultion in J and what is the qrxn in J? What is the deltaH in kJ/mol of CaCl2 dissolved?
Tuesday, September 8, 2015 by nikk

Chemistry
A 2.20 g-sample of a compound containing carbon, hydrogen, and oxygen is burned and it produces 4.61 g CO2 and 0.94 g H2O. What is the empirical formula of this compound?
Monday, September 7, 2015 by JORDAN

Chemistry
ClO- + I- → IO- + Cl- 1) What are the names of these ions? is it "The hypochlorite ion reacts with iodide ion to form iodate ion with chloride ion" ? 2) Write the general rate law (using the letters k for the rate constant, and n and m for the reaction orders...
Monday, September 7, 2015 by Ken

chemistry
What is the mass of 0.0137 mol of aspirin?
Monday, September 7, 2015 by Amanda

Chemistry
Experiment questions: Experiment 1 results mass of beaker:116.944 g mass of dodecanoic:11.629 g hot water: 175 C warm water: 10 C Average Fressing pt of Dodecanoic = 42.7 Experiment 2 results: Unknown C solution mass: 2.091g Hot water: 175C warm water: 10C average FP of UK C ...
Monday, September 7, 2015 by Jessica

Chemistry
What volume of “wet” methane would have to be collected at 20.0 oC and 760.0 torr to be sure the sample contained 2.00 x 102 ml of dry methane at the same temperature and pressure ? My Work: All I have so far is that I use P1V1=P2V2 but I don't know the ...
Monday, September 7, 2015 by Joe

AP Chemistry
An ore contains Fe3O4 and no other iron. The iron in a 39.3-gram sample of the ore is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 10.6 g. What was the mass of Fe3O4 in the sample of ore? Answer in units of g
Monday, September 7, 2015 by Sierra

AP Chemistry
A 33.8 g sample of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 20.7 g. What was the mass of iron in the sample of ore? Answer in units of g. - I Don't Even Know ...
Monday, September 7, 2015 by Allyson

Chemistry
What relationship exists between the electron structure of a Group A ion and the electron structure of the nearest noble gas? Why do boron, carbon and silicon not form simple ions? How do they satisfy their electron requirements?
Monday, September 7, 2015 by Anon

Chemistry
Elements that do not chemically react with other elements are said to be???
Monday, September 7, 2015 by Alessandra

AP Chemistry
For the reaction NH3+? O2 →? NO+? H2O , what is the maximum amount of NO (30.0061 g/mol) which could be formed from 3.79 g of NH3 (17.0305 g/mol) and 18.63 g of O2 (31.9988 g/mol)? Answer in units of g -My first thought was to balance the equation, but I have no idea ...
Monday, September 7, 2015 by Ally

chemistry
A normal salt is formed when all the hydrogen atoms in acid have been replaced by a metal.Give equation
Monday, September 7, 2015 by jack

CHEMISTRY URGENT HELP
Why are the trunks of fruit trees painted with a mixture of copper sulphate and calcium hydroxide
Monday, September 7, 2015 by saurav

chemistry
Lime water can be used to detect carbon dioxide but it cannot be used to absorb carbon dioxide. Why?
Monday, September 7, 2015 by clive

chemistry
calculate the grammes of oxygen which would be evolved on heating 5g of potassium trioxochlorate(v)
Monday, September 7, 2015 by tea

Chemistry
The solubility of potassium nitrate at 20¡ãC is 340g/litre. How many grams of KNO3 can dissolve in 185ml of water?
Monday, September 7, 2015 by Samuel

Chemistry
For the combustion of 100. gm of methane, how much heat would be generated?
Sunday, September 6, 2015 by John

chemistry
a block of metal has a width of 3.2cm, a length of 17.1cm, and a height of 3.7cm. its mass is 1.3kg. calculate the density
Sunday, September 6, 2015 by keith

Chemistry
A 78.9g sample of HCN contains 0.290g of H and 4.06g of N. Find the mass of carbon in a sample of HCN with a mass of 3.37 g
Sunday, September 6, 2015 by Mark

chemistry
What assumption did you make about the reaction of KMnO4 solution in those determinations where temp didnt change to allow k to be a constant?
Sunday, September 6, 2015 by Frank

chemistry
It took 20 seconds for a certain volume of oxygen to effuse through an orifice(small opening) at 298K. How long will it take the same volume of each of the following gases to effuse through the same orifice at the same temperature?. The gases are hydrogen, helium, and chlorine...
Sunday, September 6, 2015 by JOHN

Chemistry
when heated, sulfuric acid will decompose into sulfur trioxide and water. Write a chemical equation, using words, to represent this chemical reaction. Identify reactants and products. (I'm having trouble identifying the reactants and products & writing the chemical ...
Sunday, September 6, 2015 by Sam

Chem
A carless chemistry student pours 200 grams of methanol, a flammable substance into the sink. Another careless chemistry student causes the bad situation to get even worse by dropping a lit match into the sink. The metanol burns completely with 300 grams of oxygen from the air...
Sunday, September 6, 2015 by Sara

Chemistry
What is the difference between a chemical change and a chemical reaction?? My answer: A chemical change leads to a solidifed chemical reaction but more or less they are the same thing because it's a change in which one or more pure substances are converted into diffeent ...
Sunday, September 6, 2015 by Sam

organic chemistry
Which has higher boiling point? A. Alkenes B. Alkadienes I think my answer would be A because it contains 1 double bond (1 pi bond)
Sunday, September 6, 2015 by fay

Chemistry
If 5ml of 10M HCl was added to 1 litre of 0.4M 3-(N-morpholino) propane sulfonic acid what would be the resulting pH?
Saturday, September 5, 2015 by Katie

Chemistry HELP
What is the velocity of an electron that has a de broglie wavelength approximately the length of a chemical bond? Assume this length to be 1.2 X10^-10 m.
Saturday, September 5, 2015 by Nicole

Chemistry
Calculate the frequency of an electron traveling at 1.85X10^7 m/s.
Saturday, September 5, 2015 by Tiffie

Chemistry
What is the percentage of sand (SiO2) in a 2.88g of a mixture If 1.93 of sand was recovered upon separation?
Saturday, September 5, 2015 by Dede

chemistry
while dilution the aqueous solution of salt, a student by mistake added ethanol.which technique can be used to recover it
Friday, September 4, 2015 by nizam

Chemistry
Suppose you have two 100-mL graduated cylinders. In each cylinder, there is 40.0 mL of water. You also have two cubes: one is lead, and the other is aluminum. Each cube measures 1.8 cm on each side. After you carefully lower each cube into the water of its own cylinder, what ...
Friday, September 4, 2015 by Anonymous

Chemistry
So the answer is c,correct? The density of copper decreases as temperature increases. Which statement accurately describes the changes in a sample of copper when it is warmed from room temperature to 95 degree Celcius. a. The sample will become lighter. b. The sample will ...
Friday, September 4, 2015 by Anonymous

Chemistry
The density of copper decreases as temperature increases. Which statement accurately describes the changes in a sample of copper when it is warmed from room temperature to 95 degree Celcius. a. The sample will become lighter. b. The sample will become heavier. c. The sample ...
Friday, September 4, 2015 by Anonymous

chemistry
What is the mass of 225ml of a liquid that has a density of 0.880g/ml
Friday, September 4, 2015 by Sarah

chemistry
A square piece of paper measuring 4.8 inches on a side is weighed and found to have a mass of 1.5 grams. How many pounds would exactly 500. sheets of this paper weigh, given that each page measures 21.50 cm by 27.73 cm?
Friday, September 4, 2015 by asd

Chemistry
Which of the following is a legitimate set of n, l, m(l), and m(s) quantum numbers? a. 4, -2, -1, 1/2 b. 4, 2, 3, 1/2 c. 4, 3, 0, 1 d. 4, 0, 0, -1/2 I don't think it's c because m(s) can only have +1/2 or -1/2 but I'm not sure how to figure out the others. Could ...
Friday, September 4, 2015 by Anonymous

chemistry
why is 2-methylpropan-2-ol is an excellent solvent for oxidation reactions while propan-1-olis a poor solvent
Friday, September 4, 2015 by wellly

chemistry
Hydrogen sulfide burns in oxygen to form sulfur dioxide and water. If sulfur dioxide is being formed at a rate of 0.19 mol L-1 s-1, what are the rates of disappearance of hydrogen sulfide and oxygen? rate of disappearance of O2? rate of disappearance of H2S? I got : rate of ...
Friday, September 4, 2015 by Ken

chemistry
The radioactive isotope, phosphorus-32, has a half-life of 14.26 days. How much phosphorus-32 will remain after 60 days? Please help.
Thursday, September 3, 2015 by Ken

Chemistry
Given the following values of ΔH, ΔS and T, calculate ΔG (in kJ). The values are: ΔH = -17.0 kJ, ΔS = -50.0 J/K, and temperature = 10.0 C.
Thursday, September 3, 2015 by Jason

Chemistry
f the ΔH of fusion for aluminum is 10.9 kJ/mol and the ΔH of vaporization is 284 kJ/mol, then what is the change in entropy upon melting down an aluminum can that weighs 18.9 grams?
Thursday, September 3, 2015 by Jason

Chemistry
Determine the pH of a solution made by mixing 50,00 mL of 0,100 M nitric acid with 100 mL of 0,200 M nitric acid
Thursday, September 3, 2015 by Anonymous

Chemistry
I'm having trouble with knowing the relations between quantum numbers n, l, m(sub l), and m(sub s). Could you please explain?
Thursday, September 3, 2015 by Sarah

Chemistry
A star is estimated to have a mass of 4.4x1026lbs. It has a diameter of 8.69x105 mi. Calculate the density in g/cm3.
Thursday, September 3, 2015 by Kay

Chemistry
Write the balanced chemical equation for the reaction of the weak acid HCN with water. Include the phase of each species.
Thursday, September 3, 2015 by NA

Chemistry
Which of the following statements about isotopes is/are true? a. Because isotopes have different numbers of neutrons, they have different mass numbers. b. because neutrons determine an atom's chemical properties, isotopes of the same element are very different. C. isotopes...
Wednesday, September 2, 2015 by Aleksandra

Chemistry
why is graphing a useful way for scientists to display data?
Wednesday, September 2, 2015 by Josh

chemistry
A solution of KOH is prepared by dissolving 2.00 g of KOH in water to a final volume of 250 ml of solution what volume of this solution will neutralize 20.0 ml of 0.115 mol/L sulfuric acid? amount of KOH= 2.00g(1mol of KOH/ 56.01g)= 0.357 moles concentration of KOH in water = ...
Wednesday, September 2, 2015 by Mariam

Chemistry
In the last part of this experiment, the temperature of tap water was recorded for fifteen minutes as the tap water was heated in a beaker. Identify the dependent and independent variable. (THE TEACHER Just said THE DEPENDENT AND INDEPENDENT VARIABLE but idk if he/she wants ...
Wednesday, September 2, 2015 by Sophia

Chemistry
Which is more soluble in water? Briefly explain why. Acetic Acid: CH3CO(OH) OR Ethanol : CH3CH2OH I think its acetic acid because when observing its structure it is more polar than ethanol. And when using the like dissolves like rule, a more polar molecule with dissolve in ...
Wednesday, September 2, 2015 by Mia

Chemistry
A store owner would like to install a red illuminated sign. However, when she goes to purchase the sign, the list only includes the types of gases used, rather than the colors they produce. Which gas (H, Kr, He, Ne, Xe, or Ar) would you suggest she buy? In lay terms, explain ...
Wednesday, September 2, 2015 by Anonymous

Chemistry
Write a brief discussion of the relationship between the atomic spectrum (number and position of the lines) and the electronic structure (shell model) of the gases. I know that the bigger the atom, less energy and so does that have something to do with this question?
Wednesday, September 2, 2015 by Anonymous

Chemistry
Is it true that good accuracy of data ALWAYS indicates good precision?
Wednesday, September 2, 2015 by Denna

Chemistry
Dividing 0.32g of sulfur by its density of 2.07g/cm^3 results in an answer with three significant figures? Am I right?
Wednesday, September 2, 2015 by Robert

Chemistry
Classify each of the following as a heterogeneous mixture (M) or homogeneous mixture (S)or compound (C) or element (E). oxygen dissolved in water - S carbon mixed with sand - M apple juice - S vegetable soup -M sour, curdled milk -M steel -S hydrogen -E salt -E distilled water...
Wednesday, September 2, 2015 by anonymous

chemistry
determine the volume of oxygen calculated at STP which is liberated when 43,4g mercury oxide decomposes completely into mercury and oxygen
Wednesday, September 2, 2015 by deempho

Physical Chemistry
Calculate the difference between H and U when 1 mole of water is boiled at 373 K and 1 atm. The volume of 1 mole of perfect gas at 373 K is 0.03 m3 and the volume of liquid water may be neglected. (1 atm = 105 N m-2) what equations should be used ?
Wednesday, September 2, 2015 by S

Chemistry
Is fermentation an irreversible reaction?
Wednesday, September 2, 2015 by Stoof

chemistry
ClO3^-(aq)+3SO3^2- ¡÷ Cl^-(aq)+3SO4^2- 1) If the SO3^2- ion is disaapearing at rate of 0.458 mol/L*s, how fast is the Cl^- ion appearing? 2) if the after 10 minutes of reaction time, 1.09x10^-4 mole of Cl^- ion has been produced, how many moles of SO3^2- ion have ...
Tuesday, September 1, 2015 by Ken

Chemistry
if 75.0 ml of 1.5m sodium hydroxide reacts with 100.0 ml of 2.0m phosphoric acid, to give sodium phosphate and water, how many grams of Na3Po4 may be produced?
Tuesday, September 1, 2015 by Joe

Chemistry
determine the molarity of a solution of silver nitrate prepared by dissolving 5g of silver nitrate in 25.0mL of water
Tuesday, September 1, 2015 by Morgan

Chemistry
Explain why the appearance of the wood flame is yellow whereas the gas flame most often appears blue.
Tuesday, September 1, 2015 by Diana

Chemistry
Is the temperature of a luminous flame greater than that of a non luminous flame? Please explain.
Tuesday, September 1, 2015 by Diana

Chemistry
The meter has been defined as 1,650,763.73 wavelengths of the orange-red line of the emission spectrum of ^86Kr. Calculate the frequency of this radiation. In what proportion of the electromagnetic spectrum does the radiation fall?
Tuesday, September 1, 2015 by Anonymous

Chemistry
Is photosynthesis a reversible reaction?
Tuesday, September 1, 2015 by Stoof

Maths
In a survey of 200 students of a school, it was found that 60% study mathematics, 45% study physics, 35% study chemistry, 20% study mathematics and physics, 15% study physics and chemistry, 25% study chemistry and mathematics and 10% none of these subjects. Find the number of ...
Tuesday, September 1, 2015 by Sabah

Chemistry
Calculate the density of an unknown sample of metal given that a 2.3504 gram sample of metal causes the water level in a graduated cylinder to rise from 33.5 ml to 35.2 ml. Show work
Monday, August 31, 2015 by josh

Chemistry
Suppose that 2.091x10^-18 J is absorbed by the electron of a hydrogen atom in the n=1 energy state. Describe the final energy state of the atom.
Monday, August 31, 2015 by Anonymous

Chemistry
How much energy in joules is required to change the energy state of the H-atom electron from n=2 to n=3? from n=2 to n=4? from n=2 to infinity? Kind of confused on this concept. Could you please explain for me? Thanks
Monday, August 31, 2015 by Anonymous

Quick chemistry help
The primary purpose of the scientific method is to A. Solve problems B. Design experiments C. Make observations D. Publish theories Is it c?
Monday, August 31, 2015 by Hannah

Physical Chemistry
If 5.00 mL of 3% H2O2 is decomposed, how many mL of gas will be produced at 1.01 bar and 25C?
Monday, August 31, 2015 by Michelle

Chemistry
is concrete homogeneous or heterogeneous
Monday, August 31, 2015 by Sam

Chemistry
Determine the freezing point of an aqueous solution containing 10.50 g of magnesium bromide in 200.0 g of water.
Monday, August 31, 2015 by Zac

chemistry
The volume of 0.025M Ca(OH)2 solution which can neutralise 100ml of0.0001M H3PO4
Monday, August 31, 2015 by Arun

CHEMISTRY
A large number of hydrogen atoms have electrons excited to the nh=4.How many possible spectral lines can appear in the emission spectrum as a result of the electron reaching the ground state(n1=1)?Draw a diagram to show all path ways for the de-excitation from nh=4 ton1=1.
Monday, August 31, 2015 by BOIKETLO

chemistry
100g of stea initial at 100 degree celcius is passed through a calorimeter containing 1kg of water at 20 degree celcius. Assuming no heat loose and negligible heat capacity of the calorimeter, calculate the final temperature of the calorimeter and the content. heat of ...
Monday, August 31, 2015 by minenhle

Chemistry
If the H-atom electron in the n=1 state absorbs energy equivalent to 2.178x10^-18 J, what energy state will it occupy?
Sunday, August 30, 2015 by Anonymous

Chemistry
7) 14 carat gold has a purity of 58.3%. How many moles of gold are in 163 grams of 14 carat gold? Answer in units of moles. 8) A 15.9 g sample of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of ...
Sunday, August 30, 2015 by Yasmin

chemistry
if 1.37 moles of Pb(NO3)2 is mixed with 2.56 moles of KI, how many moles of PbI2 are produced?
Sunday, August 30, 2015 by Dave

math , physics, chemistry
sec^4x=11tan^2x+5 than what is the value of tanx
Sunday, August 30, 2015 by vikas

Chemistry
How many atoms are present in 0.3333 mol of CO2? I know I need to use the conversion factor of 6.021x10^23 but do I just multiply that times .3333? =2.007?
Sunday, August 30, 2015 by Jordan

Chemistry
The mineral cassiterite is a compound of tin and oxygen. Chemical analysis of cassiterite shows that the mass percentages of tin, Sn, and oxygen, O, are 78.8% and 21.2%, respectively. Determine the formula of this compound. I found the molar mass and correct equation SnO4. Sn-...
Sunday, August 30, 2015 by Jordan

Chemistry
The velocity of an enzyme catalyzed reaction was 10% of Vmax at 2.0 μM substrate concentration. What was the Km in μM? I know Km=1/2Vmax but I do not know if this is the right equation to use or if I am incorporating the known substrate concentration right? I tried ...
Saturday, August 29, 2015 by RJ

Chemistry
a) Biphenyl, C12H10, is a nonvolatile, nonionizing solute that is soluble in benzene, C6H6. At 25 degrees Celcius, the vapor pressure of pure benzene is 100.84 torr. What is the vapor pressure of a solution made from dissolving 13.8 g of biphenyl in 32 g of benzene? b) Express...
Saturday, August 29, 2015 by Eric

chemistry
vapour density of gas is 11.2 volume occupied by 22.4gms at STP?
Saturday, August 29, 2015 by gori

Chemistry
A syrup is added to an empty container with a mass of 104.70 g . When 0.140 pint of syrup is added, the total mass of the container and syrup is 150.01 g . (1 qt = 2 pt) 0.140 pint= 66.2 mL 150.01g mass container and syrup 104.70g mass empty container -------- 45.31 mass syrup...
Saturday, August 29, 2015 by Ann

chemistry
calculate kole fraction of hcl in solution of hcl contaning 24.8% of hcl by mass
Friday, August 28, 2015 by dipak

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