Question

*A Study in Spontaneity*

Data and Analysis

100.00 mL distilled water

*Calculated mass of* KNO3 *from prelab = 10.1
Part I KNO*

Mass of KNO3 Run1 = 10.1 | Run2 = 10.1

Initial temperature (*T**i*) Run1 = 21.8 | Run2 =
21.8

Final temperature (*T**f*) Run1 = 14.5 | Run2 =
14.5

Calculate *q**system* (*J*) =

Calculate moles of KNO3 (*mol*) =

Calculate *Δ**H* (*kJ/mol*) =

Average *Δ**H* (*kJ/mol*) =

**Use** *Δ**H – T**Δ**S
< 0* **to calculate the entropy.** Calculated
*Δ**S =*

*Calculated mass of* KOH *from prelab = 5.6
Part II KOH*

Mass of KOH Run1 = 5.6 | Run2 = 5.6

Initial temperature (*T**i*) Run1 = 22 | Run2 =
29

Final temperature (*T**f*)Run1 = 28.6 | Run2 =
35.1

Calculate *q**system* (*J*)

Calculate moles of KOH (*mol*) =

Calculate *Δ**H* (*kJ/mol*) =

Average *Δ**H* (*kJ/mol*) =

**Use** *Δ**H – T**Δ**S
< 0* **to calculate the entropy. =**

Calculated *Δ**S =*

Answer #1

Calculate enthapy

Calculate q(system) = 100 x 4.184 x (14.5 - 21.8) = 3054.32 J

moles KNO3 = 10.1/101.1032 = 0.10 mol

dH = 3054.32/0.1 x 1000 = 30.5432 kJ/mol

To calculate entropy

q(system) = 100 x 4.184 x (28.6 - 22) = 2761.44 J [Run 1]

q(system) = 100 x 4.184 x (35.1 - 29) = 2552.24 J [Run 2]

dH = 2761.44 x 56.1056/5.6 = 27.67 kJ/mol

dH = 2552.24 x 56.1056/5.6 = 25.57 kJ/mol

Average dH = 26.62 kJ/mol

Average final temperature = (28.6 + 35.1)/2 = 31.85 oC = 304.85 K

dS = 26.62/304.85 = 87.322 J/K.mol

How does the temperature change in the water correlate
to the change in the reaction????????????????
Trial 1
Trial 2
mass of baking powder (Na2cO3) added
3g
3g
mass of vinegar added
43.3 g
43.3 g
Final
temperature, tf
19.3°C
19.3°C
Initial temperature, ti
21.2°C
21.2C
Change in temperature, ∆t
1.9°C
1.9°C
q (water) = mwCwTw
368.06648 J
368.06648 J
q(reaction)
- 368.06648 J
- 368.06648 J
moles of Na2CO3
0.02830 mol
0.02830 mol
ΔH (kJ/mol)
13.006 kj/mol
13.006 kj/mol
S

CH6N2 (l) + 5 O2 (g)
→ + 2 N2 (g) + 2 CO2 (g) + 6 H2O
(l) ΔH = -2600 kJ
What is the Molar Mass H2O (2 decimal places
Minimum)? In the last conversion factor what is the ratio of Heat ÷
moles H2O from the balanced equation (4 SF Minimum) -
Is the sign + or -? ΔH (in kJ) -
Is the sign + or -?
The specific heat of ethanol is 2.46 J/goC. When...

Table 1 shows the temperature-time data were recorded for the
reaction between 50.0 mL of 1.18 M HA (a weak acid) and 50.0 mL of
0.98 M NH4OH, ammonium hydroxide (a weak base, also
known as aqueous ammonia). The solutions were mixed after 60 s of
approximately constant temperature readings of 24.20 oC.
This is the initial temperature.
Table 1: temperature-time Data
Time
(s)
Temperature
(oC)
Time (s)
Temperature
(oC)
0
24.25
90
31.22
15
24.22
105
31.12
30
24.20...

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