chemistry

posted by .

Given the thermochemical equation:

2 Al(s) + 3/2 O2(g) > Al2O3(s) ΔH = -95.7 kJ

find the heat of reaction, ΔH, for the following reaction:

2 Al2O3(s)> 4 Al(s) + 3 O2(g)
Select one:
a. -95.7 kJ
b. +95.7 kJ
c. -47.8 kJ
d. +47.8 kJ
e. +191.4 kJ

  • chemistry -

    You have the reaction as shown. You want the reverse reaction and double that. So take dH that you have, change the sign (because of the reversal) and double it.

  • chemistry -

    would it be a positive or a negative though?

  • chemistry -

    it would be e...

  • chemistry -

    yes.
    You reversed the sign because the reaction is reversed. So that makes it positive. Then double that for e.

  • chemistry -

    thank you !!!

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry

    The standard internal energy change for a reaction can be symbolized as ΔU°rxn or ΔE°rxn. For the following reaction equations, calculate the energy change of the reaction at 25 °C and 1.00 bar. Sn(s) + 2Cl2(g) --> …
  2. Chemistry

    How would you exactly start the first problem?
  3. Chemistry

    I would really like to understand how to do these problems, because my exam is coming up in a few weeks. I still cannot comprehend how you can tell if a system is is positive or negative according to reaction. For #1, I presume it …
  4. Chemistry

    I would really like to understand how to do these problems, because my exam is coming up in a few weeks. I still cannot comprehend how you can tell if a system is is positive or negative according to reaction. For #1, I presume it …
  5. Chemistry

    Given 2Al(s) + 3/2O2(g) → Al2O3(s), ΔH°f = -1,670 kJ/mol for Al2O3 (s). Determine ΔH° for the reaction 2Al2O3(s) → 4Al(s) + 3O2(g).
  6. Chemistry

    Consider the following reaction at constant P. Use the information here to determine the value of ΔSsurr at 398 K. Predict whether or not this reaction will be spontaneous at this temperature. 4 NH3(g) + 3 O2(g) → 2 N2(g) …
  7. (11) Chemistry - Science (Dr. Bob222)

    In the following hypothetical reaction A + B → C + D, the equilibrium constant, Keq is less than 1.0 at 25°C and decreases by 35% on changing the temperature to 45°C. What must be true according to this information?
  8. Chemistry

    The ΔH of the reaction below is -575.13 kJ. Is this reaction spontaneous?
  9. chemistry (Physchem)

    Calculate the standard heat of reaction at 250C (298K) and 1 atm pressure of 3FeO(s) + 2Al(s) → Al2O3(s) + 3Fe(s) in terms of per mole of Al2O3 formed, per mole of Fe formed, per mole of FeO reacted, per mole of Al reacted and …
  10. chemistry

    The standard internal energy change for a reaction can be symbolized as ΔU°rxn or ΔE°rxn. For the following reaction equations, calculate the energy change of the reaction at 25 °C and 1.00 bar. Sn(s) + 2Cl2(g) --> …

More Similar Questions