Thermodynamics

When barium hydroxide and ammonium chloride react, the temperature of the mixture decreases. What kind of reaction is this?

• Endothermic

• Decomposition

• Exothermic

• Indothermic

Tags

NGSS.HS-PS1-4

When calcium reacts with water, the temperature changes from 18°C to 39°C. Which statement is correct?

• The solution at the end is acidic

• The reaction is reversible

• The reaction is exothermic

• The reaction is endothermic

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

First Law of Thermodynamics states that (keeping in mind the sign convention of IUPAC)

• ΔU = Q + W

• ΔU = Q - W

• ΔU = W-Q

• ΔU = -W -Q

Isolated system can exchange------- with its surroundings.

• only energy

• both matter and energy

• neither matter nor energy

• only matter

If work is done by the system, the internal energy of the system decreases, then work done by the system is taken as--------

• negative

• positive

The potential energy diagram of a reaction is shown. Which statement below is correct relating to this reaction?

• represents the enthalpy change for this exothermic reaction.

• represents the enthalpy change for this endothermic reaction.

• represents the enthalpy change for this endothermic reaction.

• represents the enthalpy change for this exothermic reaction.

Tags

NGSS.HS-PS1-4

The diagram represents two solids and the temperature of each. What occurs when the two solids are placed in contact with each other?

• Heat energy flows from solid A to solid B. Solid A decreases in temperature

• Heat energy flows from solid A to solid B. Solid A increases in temperature

• Heat energy flows from solid B to solid A. Solid B decreases in temperature.

• Heat energy flows from solid B to solid A. Solid B increases in temperature.

Tags

NGSS.HS-PS3-4

Which law states that the change of enthalpy in a chemical reaction is the same regardless of whether the reaction takes place in one step or several steps, provided the initial and final states of the reactants and products are the same?

• Third Law of Thermodynamics

• Netwon's Law of Cooling

• Hess's Law

• Joule's Law of Heating

Enthalpy (H) is defined by the relation

• H = U + PV

• H = U - PV

• H = UV + P

• H = PV - U

Heat change at constant volume is

• U

• ΔU

• H

• ΔH

Tags

NGSS.HS-PS3-4