WorksheetsThermochem - Endo/Exo and Stoichiometry
Total questions: 11
Worksheet time: 27mins
2N2(g) + 3H2(g) → 2NH3(g) ΔH= 46 kJ
What is the enthalpy if 6 moles of hydrogen reacts?
92 kJ
0.143 kJ
23 kJ
15 kJ
Two cups of water, one at 100oC and the other at 50oC are poured into a larger container. What would be the final temperature of the water?
Less than 50oC.
Greater than 100oC.
Between 50oC and 100oC.
The water temperature will rise and fall continually.
C2H4(g) + H2(g) → C2H6(g) ∆H= −137 kJ
Which statement about the reaction above is correct?
reaction is exothermic and energy is released
reaction is endothermic and energy is released
reaction is exothermic and energy is absorbed
reaction is endothermic and energy is absorbed
How many moles of sulfur must react to release 5905 kJ of energy?
2S(s) + 3O2(g) →2SO3(g) ΔH= −790 kJ
7.47 moles
0.267 moles
477 moles
14.9 moles
C(s) + O2(g) → CO2(g) ∆H = –390 kJ
What is the enthalpy if 75.0 grams of carbon reacts?
6.24 kJ
-2440 kJ
-29,300 kJ
-914 kJ
Which statements about exothermic reactions are correct? (choose all that are true)
They have negative ΔH values.
The products have a lower enthalpy than the reactants.
They absorb energy from the surroundings.
They take place at faster rates than endothermic reactions.
A chemical reaction that releases heat to the surroundings is said to be ____ and has a ____ ΔH at constant pressure.
endothermic; positive
endothermic; negative
exothermic; negative
exothermic; positive
Which process is endothermic?
condensing steam into water
combustion of methane gas
freezing molten copper into a solid
sublimation of solid iodine into gaseous iodine
What is the change in internal energy of a system that absorbs 85 kJ of heat from the surroundings as it performs 20 kj of work.
105 kJ
-105 kJ
+65 kJ
-65 kJ
2Na2O2(s) + 2H2O(l) → 4NaOH(s) + O2(g) ΔH = −126 kJ
What is ΔH when 2 moles of NaOH is formed?
−126 kJ
−252 kJ
−63 kJ
+126 kJ
