Post a New Question

chem- i reallyneed help

posted by .

Consider the following equations.
N2H4(l) + O2(g) N2(g) + 2 H2O(l) ÄH = -622.2 kJ
H2(g) + 1/2 O2(g) H2O(l) ÄH = -258.5 kJ
H2(g) + O2(g) H2O2(l) ÄH = -187.8 kJ

Use this information to calculate the enthalpy change for the reaction shown below.

N2H4(l) + 2 H2O2(l) N2(g) + 4 H2O(l) ÄH = ?



i really do0nt know how to do these

  • chem- i reallyneed help -

    Add equn 1 as is, to 2x equation 2, to 2x the reverse of equation 3 to obtain the equation you want. Then add the delta H values. When you multiply an equation you must multiply delta H values too. When reversing an equation, change the sign of delta H.

  • chem- i reallyneed help -

    so is it - 764.2?

  • chem- i reallyneed help -

    oops that's me ^

  • chem- i reallyneed help -

    763.6 is what I get.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry

    Hydrazine, N2H4, is a colorless liquid used in rocket fuel. What is the enthalpy change for the process in which hydranzine is formed from its elements?
  2. Chemistry

    Hydrogen peroxide, H2O2, is a colorless liquid whose solutions are used as a bleach and an antiseptic. H2O2 can be prepared in a process whose overall change is the following. H2(g) + O2(g) H2O2(l) Calculate the enthalpy change using …
  3. chemistry

    A mixture of hydrogen peroxide, H2O2, and hydrazine, N2H4, can be used as a rocket propellant. The reaction is: 7 H2O2(g) + N2H4(l) ® 2 HNO3(aq) + 8 H2O(l) a) How many moles of H2O2 react with 0.477 mol N2H4?
  4. Chem

    RXN #1: H2 (g) + O2 (g) --> H2O2 (l) ; delta-H =?
  5. chemistry-Thermochemistry (grade 12)

    calculate enthalpy of H for the reaction N2H4(l) + 2H2O(l) -> N2(g) + 4H2)(l) Given the reactions N2H4(l) + O2(g) -> N2(g) + 2H2O(l) Enthalpy of H = -6.22.2 kJ H2(g) + (1/2)O2(g) -> H2O(l) enthalpy of H = -285.8 kJ/mol H2(g) …
  6. chemistry-Thermochemistry (grade 12)

    calculate enthalpy of H for the reaction N2H4(l) + 2H2O(l) -> N2(g) + 4H2)(l) Given the reactions N2H4(l) + O2(g) -> N2(g) + 2H2O(l) Enthalpy of H = -6.22.2 kJ H2(g) + (1/2)O2(g) -> H2O(l) enthalpy of H = -285.8 kJ/mol H2(g) …
  7. chem urgent!

    Set up a Hess's law cycle, and use the following information to calculate ÄH°f for aqueous nitric acid, HNO3(aq). You will need to use fractional coefficients for some equations. 3 NO2(g) + H2O(l) 2 HNO3(aq) + NO(g) ÄH° = -138.4 …
  8. please check my answer

    Consider the following equations. N2H4(l) + O2(g) N2(g) + 2 H2O(l) ÄH = -622.2 kJ H2(g) + 1/2 O2(g) H2O(l) ÄH = -258.5 kJ H2(g) + O2(g) H2O2(l) ÄH = -187.8 kJ Use this information to calculate the enthalpy change for the reaction …
  9. chemistry

    Hess¡¯ law says that when we add reactions together we can also add the enthalpies. Given the following set of reactions, use Hess¡¯ Law to calculate the enthalpy of the reaction given below. N2H4 + H2 ¡æ 2 NH3 ¥ÄH¡Æ = ?
  10. chemistry

    Calculate the number of moles of H2O2 required to produce 0.08 moles of HNO3 by the following reaction. 7 H2O2 + N2H4 2 HNO3 + 8 H2O

More Similar Questions

Post a New Question