Answer to Question #309684 in Chemistry for mcc

Question

Enthalpy of reaction is positive when _______________. 

a. chemical reaction is both endothermic and exothermic.

b. chemical reaction is endothermic.

c. the amount of heat transferred and absorbed are unequal.

d. chemical combustion does not happen.

When work is accomplished on the system, it _________ 

a. gains work and energy is denoted as positive.

b. gains energy and work is denoted as negative.

c. gains work and energy is denoted as zero.

d. gains energy and work is denoted as positive.

Explosion of a firecracker triggered by a spark is _________. 

a. exothermic

b. partly exothermic

c. both endothermic and exothermic

d. endothermic

Hess’s law applies the rule that enthalpy is an ________. 

a. extensive property.

b. intensive property.

c. extensive process.

d. intensive process

Answer 1

Solution:

(B) Enthalpy of reaction is positive when chemical reaction is endothermic.

(D) When work is accomplished on the system, it gains energy and work is denoted as positive.

(A) Explosion of a firecracker triggered by a spark is exothermic reaction.

(A) Hess’s law applies the rule that enthalpy is an extensive property.