3) The value of ??\' for the reaction below is 126 kJ How much heat (in k ) is r

Question

3) The value of ??' for the reaction below is 126 kJ How much heat (in k ) is released when 2.00 mol of NaOH is formed in the reaction? 2Na202 (s) + 2H20() 4NaOH (s) + 02(8) A) 252 B)-126 C) 7.8 D) 63 E) 3.9 4) The value of AH for the reaction below is -790 kJ. The enthalpy change accompanying the reaction of 0.95 g of S is kJ. 2S (s)+ 302 (g) 2s03 (g) A) -23 B) 12 C)-12 D) 23 E) -790 5) The value of AH for the reaction below is -6535 kJ. How many kJ of heat are released in the combustion of 16.0 g of CoH6 ()? C6H6 () + 1502 (g) 12CO2 (g) + 6H20 (i) A) 673 B) 2.68 x 103 C) 5.23 x 104 D) -6535 E) 1.34 x 103

Explanation / Answer

Answer:

3) Given reaction is

2Na2O2(s) + 2H2O(l) --------> 4NaOH(s) + O2(g) ?H°=-126kJ

From the reaction, for 4 moles of NaOH formation 126 kJ heat is released then for 2 mol of NaOH formation,

heat released=(2 mol x 126 kJ)/4mol=63 kJ.

So option (D) is correct.

4) Given reaction is

2S(s) + 3O2(g) --------> 2SO3(g) ?H°=-790 kJ

Given mass of S=0.95 g and molar mass of S=32 g/mol

Therefore moles of S=0.95 g /32 g/mol=0.02968 mol.

For 2 moles of S, the enthalpy change=-790 kJ, then for 0.02968 mol S, how much enthalpy change

Enthalpy change=(0.02968 mol x -790 kJ)/2mol

=-11.72~ -12 kJ.

Option (C) is correct.

4) Given reaction is

2C6H6(l) + 15O2(g) -------> 12CO2(g) + 6 H2O(l) ?H°=-6535 kJ

Given mass of C6H6=16 g and

molar mass of C6H6=78.11 g/mol

Moles of C6H6=16g/78 g/mol=0.205 mol.

For 2 mol of C6H6 heat released=6535kJ, then for 0.2048 mol, heat released=(0.205 mol x 6535 kJ)/2 mol=673 kJ

Option (A) is correct.

As per our guidelines I have to answer first question but I answered all for you. Please let me know if you need any help.

Thanks and please give me rating.

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.