Heat of Formation

Q. The value of standard enthalpy of formation of $S{F}_6\left(g\right),S\left(g\right)andF\left(g\right)are-1100,275,80kJ/mol$ respectively. The average bond energy of $S{F}_6$ (in kJ/mol) is
(Give your answer to the nearest answer)

Q.

The standard enthalpies of formation of $C{O}_2\left(g\right)$, $H_{2}O\left(l\right)$ and glucose(s) at ${25}^{\circ }C$ are $-400kJ/mol$, $-300kJ/mol$ and $-1300kJ/mol$, respectively. The standard enthalpy of combustion per gram of glucose at ${25}^{\circ }C$ is

1. + 2900 kJ

2. −2900 kJ

3. −16.11 kJ

4. +16.11 kJ

Q. Standard molar enthalpy of formation of $C{O}_2$ is equal to

1. Zero
2. The standard molar enthalpy of combustion of gaseous carbon
3. The sum of standard molar enthalpies of formation of CO and $O_2$
4. The standard molar enthalpy of combustion of carbon (graphite)

Q. From the following reactions, heat of formation of $S{O}_{2\left(g\right)}$ is
$S_{\left(g\right)}+\frac{3}{2}{O}_{2\left(g\right)}\to S{O}_{3\left(g\right)}+2xkcal$
$S{O}_{2\left(g\right)}+\frac{1}{2}{O}_{2\left(g\right)}\to S{O}_{3\left(g\right)}+ykcal$

1. x + y
2. 2x + y
3. x - y
4. 2x - y

Q. The species which by definition has ZERO standard molar enthalpy of formation at 298 K is

1. Br₂(g)

2. Cl₂(g)

3. H₂O(g)

4. CH₄(g)

Q. The standard heat of formation of diamond is

1. Less than that of graphite
2. Zero
3. Same as that of graphite
4. Greater than that of graphite

Q. For which of the following reactions $\Delta H_{reaction}$ is equal to $\Delta H_{formation}$

1. 
2. 
3. 
4. 

Q. Calculate the heat of formation of acetic acid from the following data.

$C{H}_{3}COOH\left(l\right)+2O_2\left(g\right)\to 2C{O}_2\left(g\right)+2H_{2}O\left(l\right),△H=-207.9Kcal$
$C\left(s\right)+O_2\left(g\right)\to CO2\left(g\right)△H=-94.48Kcal$
$H_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to H_{2}O\left(l\right)△H=-68.4Kcal$

1. 117.86 K cal

2. -117.86 K cal

3. 116.86 K cal

4. -116.86 K cal

Q. The enthalpy of formation of two compounds A and B are -84 kJ/mol and -156 kJ/mol respectively. Which of the following statements about A and B are correct?

1. A is less stable than B
2. Both A and B are unstable
3. Both A and B are endothermic compounds
4. A is more stable than B

Q. Which of the following equations correctly represents the standard heat of formation of methane

1. $C\left(graphite\right)+2H_2\left(g\right)=C{H}_4\left(l\right)$
2. $C\left(graphite\right)+2H_2\left(g\right)=C{H}_4\left(g\right)$
3. $C\left(graphite\right)+4H=C{H}_4\left(g\right)$
4. $C\left(diamond\right)+2H_2\left(g\right)=C{H}_4\left(g\right)$