Complete the sentence: When heat is transferred to the system, the process is sa

Question

Complete the sentence: When heat is transferred to the system, the process is said to be _____, and the sign of q is _____. A) endothermic, positive B) exothermic, positive C) exothermic, negative D) forbidden, indeterminate E) endothermic, negative What is q if 28.6 g of water is heated from 22.0 degree C to 78.3 degree C? The specific heat of water is 4.184 J/g middot degree C. A) 9.37 kJ B) 2.63 kJ C) 3.94 times 10^4 kJ D) 6.74 kJ E) 2.60 J What is Delta H degree_rxn for the following reaction? Delta H degree_f (H_2 O(l)) = -285.8 kJ/mol, Delta H degree_f (H_2 O_2 (l)) = -187.6 kJ/mol A) 98.2 kJ/mol B) -196.4 kJ/mol C) -98.2 kJ/mol D) -946.8 kJ/mol E) -473.4 kJ/mol The solar radiation spectrum peaks at a wavelength of approximately 500 nm. Calculate the energy of one photon of that radiation (c = 3.00 times 10^8 m/s; h = 6.63 times 10^-34 J middot s). A) 1 times 10^-27 J B) 6 times 10^14 J C) 2 times 10^-25 J D) 4 times 10^-19 J E) 4 times 10^-10 J

Explanation / Answer

18 ) A

19 ) D

q = mc(delta C)

q = ( 28.6 g ) * ( 4.184 j/g c) * ( 78.3 - 22.0 c)

q = 6736 j = 6.74KJ

20) B

[ 2 ( delta Hf [H2O])] - [ 2 ( delta Hf [H2O2])] = delta H

2 ( - 285.8) - 2 ( -187.6) = -196.4 Kj/mol

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

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