A 35.6 g sample of ethanol (C_2H_5OH) is burned in a bomb calorimeter, according

Question

A 35.6 g sample of ethanol (C_2H_5OH) is burned in a bomb calorimeter, according to the following reaction. If the temperature rose from 35.0 to 76.0 degree C and the heat capacity of the calorimeter is 23.3. kJ/degree C, what is the value of Delta H_rxn degree? The molar mass of ethanol is 46.07 g/mol. C_2H_5OH(I) + 3 O_2(g) rightarrow 2 CO_2(g) + 3 H_2O(g) Delta H_rxn degree = ? Determine the specific heat capacity of an alloy that requires 59.3 kJ to raise the temperature of 150.0 g alloy from 298 K to 398 K. Which of the following is TRUE if Delta E_sys = - 97 J? A piece of iron (C = 0.449 J/g degree C) and a piece of gold (C = 0.128J/g degree C) have identical masses. If the iron has an initial temperature of 498 K and the gold has an initial temperature of 298 K, which of the following statements is TRUE of the outcome when the two metals are placed in contact with one another? Assume no heat is lost to the surroundings.

Explanation / Answer

1)since temperature is increased, so dH has to be negative. so,

moles of ethanol = 35.6/46

=0.774

dH=-23.3*(76-35)/0.774

=-1.24*10^3 kJ/mol

2)let it be x.so,

x*150*(398-298)=59.3*10^3

or x=3.95 J/gC

3)since it is negative, the system is losing energy(as it is being given out) and the surrounding is gaining energy

4)the first statement is true since the heat energy change is proportional to the specific heat capacity.

let the final temp be T.so,

0.449*(498-T)=0.128*(T-298)

or T=453.633 C

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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