# Chemistry

Consider the following three reactions:
Ca(s) + 2H2O(l) ---> Ca2+(aq) + 2OH^- (aq) + H2(g)

CaO(s) + H2O(l) ---> Ca2+ (aq) + 2OH^- (aq)

H2(g) + 1/2O2 (g) ----> H2O (l)

Delta H = 430.75 kJ
Delta H = 81.55 kJ
Delta H = 285.63 kJ

Determine Delta H for the overall reaction:
Ca(s) + 1/2O2 (g) ---> CaO(s)

1. 👍 0
2. 👎 0
3. 👁 100
1. Add eqn 1 to eqn 3 to the reverse of eqn 2. Add the dH values; when you reverse the rxn change the sign of dH for that rxn.
Post your work if you get stuck.

1. 👍 0
2. 👎 0
posted by DrBob222

## Similar Questions

1. ### Chem

Which of the following is the formation reaction for CaO(s) ? A. CaO(s) Ca(s) + 21O2(g) B. Ca2+(aq) + O2–(aq) CaO(s) C. 2 Ca(s) + O2(g) 2CaO(s) D. Ca(s) + 21O2(g) CaO(s). E. 2 CaO(s) 2 Ca(s) + O2(g) I know that you have to

asked by Anonymous on February 24, 2008
2. ### someone correct my work please? fun, fun chemistry

Okay. I'm very, very confused. The initial question is: predict the products of the electrolysis of a 1 mol/L solution sodium chloride. This is my work: The four different possible equations are: 2H2o + 2e- -------> H2 + 2OH- (V=

asked by Rienna on January 30, 2007
3. ### chemistry

Which of the following is the formation reaction for CaO(s) ? can you check my answer(the one that has star next to it) A. Ca(s) + 1/2O2(g)= CaO(s). B. CaO(s)= Ca(s) + 1/2O2(g) C. Ca2+(aq) + O2–(aq)= CaO(s) D. 2 Ca(s) + O2(g)=

asked by blasting on February 11, 2010
4. ### Chemistry

Can someone check my answers for me thank you. I have the equation balanced below. 2H2O + K2SO4 --> H2SO4 + 2KOH Ionic equation for the reaction between sulfuric acid and potassium hydroxide. 2H+ + SO4^2- + 2K+ + 2OH- --> 2K+ +

asked by Susie on January 13, 2008
5. ### Chemistry

Can someone please help me with this question? Hydrazine is somewhat toxic. Use the half-reactions shown be- low to explain why household bleach (a highly alkaline solution of sodium hypochlorite) should not be mixed with

asked by Anonymous on June 7, 2015
6. ### Chemistry

Which of the following is the formation reaction for CaO(s) ? A. Ca2+(aq) + O2–(aq) CaO(s) B. Ca(s) + .5O2(g) CaO(s). C. CaO(s) Ca(s) + .5O2(g) D. 2 Ca(s) + O2(g) 2CaO(s) E. 2 CaO(s) 2 Ca(s) + O2(g) Left with B and D. Please

asked by Tom on May 17, 2008
7. ### chemistry

"Write equations for the half-reactions that occur at the anode and cathode for the electrolysis of the following aqueous solution: CuBr2(aq)" Possible oxidation reactions: 1. 2Br- -> Br2 + 2e- = -1.09 2. 2H2O -> O2 + 4H+ + 4e- =

asked by Kate on April 2, 2014
8. ### chemistry

Which of the following is the formation reaction for CaO(s) ? A. CaO(s) Ca(s) + 21O2(g) B. Ca2+(aq) + O2–(aq) CaO(s) C. Ca(s) + 21O2(g) CaO(s). D. 2 Ca(s) + O2(g) 2CaO(s) E. 2 CaO(s) 2 Ca(s) + O2(g)

asked by eli on February 22, 2010
9. ### Chemistry

Performing a gravimetric analysis of Ca2+. 25 mL of unknown [Ca2+} added to 25 mL of 0.15 (NH4)2C2O4 and 75 mL of HCl. Urea also added. H2NCONH2 + 3H2O --heat→ CO2 + 2NH4 + 2OH CaC2O4*H2O --> Ca2+ + C2O42- [Ca2+]unknown=0.06028

asked by Anonymous on March 25, 2013
10. ### Chemistry

A solution is 0.20 M in Cd2+ and 0.20 M in Ca2+. NaOH solution is added slowly through a burette. Ca(OH)2 (s) Ca2+ (aq) +2OH (aq) Ksp= 5.5*10^-6 Cd(OH)2 (s) Cd2+ (aq) +2OH (aq) Ksp= 2.5*10^-14 Calculate the concentrations of

asked by Sally on April 5, 2018

More Similar Questions