Question

Check my answers please? Only 5 multiple choice questions. I'm really confused. Any and all help is appreciated! Will give medal!

1. Which of the following is a correctly written thermochemical equation?

NH4Cl NH4+ + Cl
2C8H18 + 25O2 16CO2 + 18H2O, H = 5,471 kJ/mol
Fe (s) + O2 (g) Fe2O3 (s), H = 3,926 kJ
-->C3H8 (g) + 5O2 (g) 3CO2 (g) + 4H2O (l), H = 2,220 kJ/mol
2. How does a phase change affect a thermochemical equation?

It alters the moles of reactants.
-->It can affect the (delta) H value.
It alters the products.
It affects the balance of the equation.

Answer 1

3. For the reaction CH4 (g) + 2O2 (g) CO2 (g) + 2H2O (l), H = 890 kJ, what will be the change in enthalpy when 3 moles of methane react in excess oxygen?

890 kJ

-->2.67 × 103 kJ

+890 kJ

+2.67 × 103 kJ

4. In which of the following thermochemical equations would the H be considered a heat of solution?

NH4Cl (s) NH4+ (aq) + Cl (aq), H = + 14.8 kJ/mol

2C8H18 (l) + 25O2 (g) 16CO2 (g) + 18H2O (l), H = 5,471 kJ/mol

-->4Fe (s) + 3O2 (g) 2Fe2O3 (s), H = 3,926 kJ

C3H8 (g) + 5O2 (g) 3CO2 (g) + 4H2O (l), H = 2,220 kJ/mol

5. For the following reaction at STP, how much heat will be required to produce 63 L of NO? (At STP, one mole of any gas occupies 22.4 L.)

N2 (g) + O2 (g) 2NO (g), H = 180.5 kJ

+63 kJ

+127 kJ

-->+254 kJ

+508 kJ

Answer 2

Are they alright?

Answer 3

All but number 4 are correct, it should be NH4Cl (s) NH4+ (aq) + Cl (aq), H = + 14.8 kJ/mol

Answer 4

Alright, thanks for responding...I'm long done with this by now but thank you anyways! :) I appreciate it!