Enthalpy and Entropy

The __________ law of thermodynamics states that entropy is always increasing. 

• first
• second
• third
• zeroth

Temperature is a measure of average _________ energy of individual atoms.

• heat

• potential

• mechanical

• kinetic

Tags

NGSS.HS-PS3-2

ΔH value in an endothermic reaction is a positive number.

• True
• False

Which phase of matter has the greatest motion and least orderly arrangement?

• solid
• liquid
• gas

Tags

NGSS.MS-PS1-4

The equation that relates enthalpy, temperature and entropy is

• Hess's Law
• Second Law of Thermodynamics
• Gibbs Free Energy
• Calorimetry

 For which of these processes is the value of ΔH expected to be positive?
1.  The temperature increases when calcium chloride dissolves in water.
2.  Steam condenses to liquid water
3.  Water boils
4.  Dry ice sublimates

• 4 only
• 1 only
• 3 and 4 only
• 2 and 3 only

6.  The formation ½ A2 + 2 B2 + C --> CAB4 has an enthalpy of formation of -104 kJ and a change in entropy of -60.8 J/K at 30 °C. What is the free energy and spontaneity of the reaction?  

• -85.6 kJ, spontaneous
• -18.3 kJ, not spontaneous
• +18.3 kJ, spontaneous 
• +85.6 kJ, not spontaneous 

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

When a liquid boils what are the signs for Δ H  and  Δ S  ? (Think about H₂O as an example!)

• Δ H  =  +   Δ S  =  +
• Δ H  =  -   Δ S  =  -
• Δ H  =  +   Δ S  =  -
• Δ H  =  -   Δ S  =  +

Tags

NGSS.HS-PS3-4

Spontaneity is determined by....

• enthalpy only
• entropy only
• enthalpy and entropy
• enthalpy, entropy, and temperature

Solid magnesium dissolves in a solution of hydrochloric acid, releasing hydrogen gas and heat from a solution of magnesium chloride. What is the sign on ΔG for this reaction?

• Negative because it is spontaneous
• Negative because it is nonspontaneous
• Positive because it is spontaneous
• Positive because it is nonspontaneous

Tags

NGSS.HS-PS3-1