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  • improper integral?

    integral from 6 to 8

    4 / (x-6)^3 dx

    1 AnswerMathematics1 decade ago
  • improper integrals. please help asap. thanks.?

    integral from infinite to 0

    e^2 / e^(2x) + 3 dx

    2 AnswersMathematics1 decade ago
  • definite integral using the substitution rule?

    if f is continuous and integral from 9 to 0 f(x) dx=4

    find integral 3 to 0 xf(x^2) dx

    please help thanx.

    2 AnswersMathematics1 decade ago
  • indefinite integral question?

    USe the substitution rule

    x divided by squareroot of x^2 +1

    what would be the indefinite integral of that ? use substitution rule. thankx

    5 AnswersMathematics1 decade ago
  • How many possible four aminoacid long peptides (a peptide is a small protein) can be made from the below pepti

    How many possible four aminoacid long peptides (a peptide is a small protein) can be made from the below peptides.

    (I.E. rearrange them to form different sequences, where each sequence is made up of only the four aminoacids given below)

    met trp met trp

    Enter a whole number numerical answer.

    3 AnswersChemistry1 decade ago
  • Which of the following statements are true for the reactions that precede them.?

    Which of the following statements are true for the reactions that precede them.

    NOTE: Read the equations left to right

    a) NH3 + H2O ↔ NH4 + + OH − NH3 is the Lewis base

    b) HF + H2O ↔ H3O + + F &minus Water is the Lewis acid

    c) C5H5N + H2O ↔ C5H5NH + + OH &minus Water is the Lewis base

    d) Al(H2O)6 3+ + H2O ↔ H3O + + Al(H2O)5OH 2+ Al(H2O)6 3+ is the Lewis acid

    e) NH4 + + H2O ↔ H3O + + NH3 Water is the Lewis acid

    1 AnswerChemistry1 decade ago
  • calculate the percent yield?

    For the reaction BaI2 + MgSO4 (aq) BaSO4 precipitates out.

    Calculate the percent yield (%) if 18.052 g of BaSO4 precipitates

    when 1.950 L of 0.0550 M BaI2 and 2.100 L of 0.0426 M MgSO4 (aq) are mixed.

    Enter a numeric answer only

    1 AnswerChemistry1 decade ago
  • optical isomers?

    WHAT MAKES A chemical structure..optical isomer?!?!?!?!?!?! how do you count how many there are?!?! please tell me I need to know! thanx!

    4 AnswersChemistry1 decade ago
  • isomers and isomerism?

    Which of the following are true statemtents about isomers/isomerization ?

    a) Looking at a pair of Optical isomers one would see the same

    chemical bonds, however these bonds would have different spatial arrangements in each isomer

    b) Optical isomers always have identical chemical properties

    c) A thumbtack and its mirror image are identical, they are superimposable

    d) The mirror image of your left hand appears the same as your left hand, i.e. superimposable

    3 AnswersChemistry1 decade ago
  • exceptions to the octet rule?

    Which of the following compounds present exceptions to the octet rule ?

    a) PF5

    b) XeF4O

    c) XeF6

    d) ClO3-

    e) BrF3

    NOTE: condsider formal charges when drawing Lewis structures

    1 AnswerChemistry1 decade ago
  • resonance structure?

    Choose those statements that are true for the most stable resonance structure of the molecules H−C−N and C−N−H

    a) Both of these structures have a triple bond between the carbon and nitrogen atoms

    b) Both of these structures have a positive charge on the nitrogen atom

    c) CNH is predicted to be more stable than HCN

    d) One resonance structure has eight valence electrons and the other has ten valence electrons

    e) These two resonance structures are resonance structures of different molecules

    3 AnswersChemistry1 decade ago
  • Resonance structures..chemistry help plz?

    Choose those statements that are true for the most stable resonance structure of the molecules H−C−N and C−N−H

    a) Both of these structures have a triple bond between the carbon and nitrogen atoms

    b) Both of these structures have a positive charge on the nitrogen atom

    c) CNH is predicted to be more stable than HCN

    d) One resonance structure has eight valence electrons and the other has ten valence electrons

    e) These two resonance structures are resonance structures of different molecules

    2 AnswersChemistry1 decade ago
  • chemistry- energy change PLZZZZ HELp!?

    calculate the energy change in kJ for the formation of 0.25 mol of NaI(s)

    given the following information: I2(s) ? I2(g) : 62.44 KJ/mol

    Na(s) ? Na(g) : 107.32 KJ/mol

    I2(g) ? 2I(g) : 276.10 KJ/mol

    Na+(g) + e- ? Na(g) : -496 KJ/mol

    Electron affinity for I(g) : -295.16 KJ/mol

    Lattice energy for NaI = -702 KJ/mol

    1 AnswerChemistry1 decade ago
  • help meee! chemistry! experts help!?

    Using average bond energy values estimate ?H for the following gas phase reaction.

    2CH2=CHCH3 + 2NH3 + 3O2 produces-> 2CH2=CHCN + 6H2O

    please tell me how u arrived at htat answer.i've tried sO many times i keep getting it wrong! thanx!

    1 AnswerHomework Help1 decade ago
  • bond energy and energy related chemistry question?

    Using average bond energy values estimate ?H for the following gas phase reaction.

    2CH2=CHCH3 + 2NH3 + 3O2 ? 2CH2=CHCN + 6H2O

    ANOTHER QUESTION:

    Calculate the energy change in kJ for the formation of 0.25 mol of NaI(s)

    given the following information: I2(s) ? I2(g) : 62.44 KJ/mol

    Na(s) ? Na(g) : 107.32 KJ/mol

    I2(g) ? 2I(g) : 276.10 KJ/mol

    Na+(g) + e- ? Na(g) : -496 KJ/mol

    Electron affinity for I(g) : -295.16 KJ/mol

    Lattice energy for NaI = -702 KJ/mol

    Enter a numerical answer only, do not enter units.

    im jsut stuck on these two. please explain how u got the answer. thanx! it'll be great help!

    2 AnswersHomework Help1 decade ago
  • chesmitry sis and trans isomers. EXPERTS PLEASE?

    Which of the following compounds can exist as cis and trans isomers ?

    a) CH2=CHF

    b) CHCl=CH-CH2Cl

    c) HClCFCl

    d) CBrBr=CH-CH2Cl

    e) 3-hexene

    please explain how uk now when something is both cis and trans isomer. thanx.

    1 AnswerHomework Help1 decade ago
  • chemistry problem!!! ADVANCED?

    (H-C=N-H)+ with two electrons on top of N...like two dots on top of N.

    Choose the statements that are true about the proposed Lewis structure shown above for the molecule [HCNH]+.

    Base your answers on the struture as drawn here.

    a) For this Lewis structure the number of valence electrons shown is correct

    b) All of the atoms have an octet of electrons

    c) In this Lewis structure the formal positive charge is on the carbon atom

    d) This is the best Lewis structure for the molecule [HCNH]+

    2 AnswersHomework Help1 decade ago
  • cheMISTRY!?

    Which of the following compounds can exist as cis and trans isomers ?

    a) CH2=CHF

    b) CHCl=CH-CH2Cl

    c) HClCFCl

    d) CBrBr=CH-CH2Cl

    e) 3-hexene

    please explain how uk now when something is both cis and trans isomer. thanx.