Question

How much heat is evolved in converting 1.00 mol of steam at 145.0 ∘C to ice at -55.0 ∘C? The heat capacity of steam is 2.01 J/(g⋅∘C) and of ice is 2.09 J/(g⋅∘C).

Answer 1

Answer:

Heat evolved = 57.9 kJ i.e. -57.9 kJ

Explanation:

The transition from steam at 145 C to ice at -55 C involves the following steps:

Step 1: Heat involved in the change from steam at 145 C to steam at 100 C

$q1 = mc(T2-T1)\\\\m = mass\ of\ steam\\\\c = heat\ capacity\ of\ steam\\\\T2, T1 = final\ and\ initial\ temperatures$

Moles of steam (H2O)= 1 mole

Molar mass of H2O = 18 g/mol

$Mass\ of\ steam,\ m = moles*molar\ mass= 1 mole*18 g/mol= 18\ g\\\\c = 2.01 J/gC\\\\T2-T1 = 100-145 = -45 C\\\\q1 = 18 g*2.01J/gC *(-45C) = -1628.1J= -1.628\ kJ$

Step 2: Phase change from steam at 100 C to water at 100 C

$q2 = n\Delta H(cond)$

where ΔH(cond) = heat of condensation = -40.7 kJ/mol

n = number of moles$q2 = 1\ mole*(-40.7\ kJ/mol)= -40.7\ kJ$

Step 3: Heat involved in the change from water at 100 C to water at 0 C

$q3 = mc(T2-T1)\\\\m = mass\ of\ water\\\\c = heat\ capacity\ of\ water\\\\T2, T1 = final\ and\ initial\ temperatures$

$q3 = 18 g*4.18J/gC *(-100C) = -7524J= -7.524\ kJ$

Step 4: Phase change from water at 0 C to ice at 0 C

$q4 = n\Delta H(cond)$

where ΔH(fusion) = -6.01 kJ/mol

n = number of moles$q4 = 1\ mole*(-6.01\ kJ/mol)= -6.01\ kJ$

Step 5: Heat involved in the change from ice at 0 C to ice at -55 C

$q5 = mc(T2-T1)\\\\m = mass\ of\ water\\\\c = heat\ capacity\ of\ ice\\\\T2, T1 = final\ and\ initial\ temperatures$

$q5 = 18 g*2.09J/gC *(-55C) = -2069.1\ J= -2.069\ kJ$

Step 6: Total heat evolved

$q = q1+q2+q3+q4+q5$

q = -1.628 -40.7 -7.524-6.01-2.069 = -57.9 kJ

Answer 2

The study of chemicals is called chemistry. There are two type of solution in the chemistry and these are acid and base.

The correct answer to the question is as follows:- 57.9kj.

Heat capacity?

• Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature.
• The SI unit of heat capacity is joule per kelvin. Heat capacity is an extensive property.

The data is given as follows:-

• moles of h2o steam is 1 mole
• molar mass of h2o is 18

Mass will be$18*1$ = 18gram

Temperature variation is $T_2-T_1=100-145=-45C$. Therefore the charge q is as follows:-

$q=18g*20.1*-45=1628.1J$

Repeat this step for every reaction and you will get all the heat capacity. The final heat capacity is as follows:-

$q_1+q_2+q_3+q_4$

$q = -1.628 -40.7 -7.524-6.01-2.069 = -57.9 kJ$

Hence, the correct answer to the question is - 57.9kj.

For more information about the heat capacity, refer to the link:-

https://brainly.com/question/1453843