Enthalpy and Thermochemistry Test

Calculate the enthalpy of the following chemical reaction:

2C(s) + H2(g) ---> C2H2(g) DH° = ??? kJ

Given the following thermochemical equations:

C2H2(g) + (5/2)O2(g) ---> 2CO2(g) + H2O(l) DH° = -1299.5 kJ

C(s) + O2(g) ---> CO2(g) DH° = -393.5 kJ

H2(g) + (1/2)O2(g) ---> H2O(l) DH° = -285.8 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Fe (s) + 3 O₂ (g) → 2 Fe₂O₃ (s) + 1625 kJ

Is this reaction endothermic or exothermic?

• endothermic

• exothermic

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Ice cream melting is an example of an __________ process.

• endothermic

• exothermic

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Which phrase best describes the reaction: N₂(g) + O₂(g)+ 182.6 kJ→2NO(g)

• Endothermic with ΔH= -182.6 kJ

• Endothermic with ΔH= +182.6 kJ

• Exothermic with ΔH= -182.6 kJ

• Exothermic with ΔH= +182.6 kJ

Tags

NGSS.HS-PS1-4

Sweating is an __________________ process because heat is released.

• endothermic

• exothermic

Tags

NGSS.HS-PS3-4

If 400 grams of water at 70 degrees C loses 9750 J of heat, what is the final temperature of the water?

• 4.184 J/gC

• 5.8 C

• 76 C

• 64 C

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

What is calorimetry?

• process of measuring kinetic and potential energy

• process of measuring heat flow of chemical reactions

• process of measuring pressure and temperature of a substance

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

50 grams of an unknown substance undergoes a temperature increase of 35 degrees C after absorbing 4172.4 Joules. What is the c of the substance?

• 2.44 J/gC

• 3523.36 J/gC

• 7134804 J/gC

• 2.38 J/gC

Tags

NGSS.HS-PS3-1

Samples of two different substances having the same mass always have the same heat capacity. True or False?

• True

• False

Calculate the number of joules needed to freeze 55 grams of liquid ammonia at its freezing point to produce solid ammonia where heat of fusion is 2500J/g and heat of vap. is 1374J/g.

• 71.43 J

• 39.26 J

• 137500 J

• 48090 J

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4