Explain why the extrapolated temperature is used to determine the maximum temper

Question

Explain why the extrapolated temperature is used to determine the maximum temperature of the mixture rather than the highest recorded temperature in the experiment. See Figure 25.5. Experimental Procedure, Part B. Three student chemists measured 50.0 mL of 1.00 M NaOH in separate Styrofoam coffee cup calorimeters (Part B). Brett added 50.0 mL of 1.10 M HCI to his solution of NaOH; Dale added 45.5 mL of 1.10 M HCI (equal moles) to his NaOH solution. Lyndsay added 50.0 mL of 1.00 M HC1 to her NaOH solution. Each student recorded the temperature change and calculated the enthalpy of neutralization. Identify the other two Identify the student who observes a temperature change that will be different from that observed by chemists. Explain why and how (higher or lower) the temperature will be different.

Explanation / Answer

3) the reaction is

NaOH + HCl --------------> NaCl +H2O

No.1 50x1.00 50x1.1   

= 50 =55

N0.2 50 45.5x1.1 = 50.05

No.3 50 50x1.00 = 50

In each case the heat liberated will be the same as the number of moles of acid and base are same..

we know heat relased = mass x specific heat of water x rise in temperature

As heat , sp.heat are same the rise in temperature is inversely proportional to mass.

Thus the solution with more mass gives lower rise in teperature.

Thus the solutionof students Brett = 100mL = 100g

dale = 95.5 mL = 95.5 g

Lyndsay = 100ml = 100g

Hence Dale gets higher temperature rise than other two as his mass is less .

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

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