258 kj to calories

1. Expressing amounts of energy in different energy units is necessary to solve many chemistry problems. For practice, complete the following table.

The Joule (J) is the SI unit of energy. 1 calorie (cal) = 4.184 J

J

cal

kJ

656

132

0.736

B Expressing amounts of energy in different energy units is necessary to solve many chemistry problems. For practice, complete the following table.

The Joule (J) is the SI unit of energy. 1 calorie (cal) = 4.184 J

J

kJ

kcal

656

0.703

0.115

C. The nutritional label on the package indicates that a package of crackers contains 166 Calories. Express this value in kJ and in J.

kJ J 1 cal = 4.184 J

2. An automobile engine provides 632 Joules of work to push the pistons. In this process the internal energy changes by -2966 Joules. Calculate the amount of heat that must be carried away by the cooling system. q = Joules

B. A chemical reaction is run in which 163 Joules of heat are absorbed and 262 Joules of work are done by the system. Calculate the change in the internal energy of the chemical system. http://cxp.cengage.com/contentservice/assets/T=1446652789472/owms01h/mediaarchives/GenChem/Image/delta16-1.GIFE = Joules

C. An automobile engine provides 510 Joules of work to push the pistons and generates 2121 Joules of heat that must be carried away by the cooling system. Calculate the change in the internal energy of the engine. http://cxp.cengage.com/contentservice/assets/T=1446652789472/owms01h/mediaarchives/GenChem/Image/delta16-1.GIFE = Joules

3. When 1 mole of H2(g) reacts with Cl2(g) to form HCl(g) according to the following equation, 185 kJ of energy are evolved.

H2(g) + Cl2(g) http://cxp.cengage.com/contentservice/assets/T=1446652789472/owms01h/mediaarchives/GenChem/Image/Arrow.gif 2HCl(g)

Is this reaction endothermic or exothermic? What is the value of q? kJ

B When 2 moles of H2S(g) react with O2(g) to form H2O(l) and SO2(g) according to the following equation, 1.12×103 kJ of energy are evolved.

2H2S(g) + 3O2(g)