Thermochemistry Concepts

Which statement correctly describes an endothermic chemical reaction?

• The products have higher potential energy than the reactants, and the ΔH is negative.

• The products have higher potential energy than the reactants, and the ΔH is positive.

• The products have lower potential energy than the reactants, and the ΔH is negative.

• The products have lower potential energy than the reactants, and the ΔH is positive.

Tags

NGSS.HS-PS1-4

As water boils, the heat transfer through the water is best described as

• convection

• conduction

• radiation

• insulation

Tags

NGSS.HS-PS3-4

The measure of average kinetic energy is called a.

• Temperature

• Pressure

• Volume

• Heat

Tags

NGSS.HS-PS3-2

A chunk of ice whose temperature is –20ºC is added to an insulated cup filled with water at 0 ºC. What happens in the cup?

• The ice melts until it reaches the temperature of the water.

• The water cools until it reaches the temperature of the ice.

• Some of the water freezes, so the chunk of ice gets larger.

• none of the above

Tags

NGSS.HS-PS3-4

What would likely happen if you were to touch the flask in which an endothermic reaction was occurring?

• The flask would probably feel cooler than before the reaction started.

• The flask would probably feel warmer than before the reaction started.

• The flask would feel the same as before the reaction started

• none of the above

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

If heat is released by a chemical system, an equal amount of heat will be ____.

• absorbed by the surroundings

• released by the surroundings

• absorbed by the universe

• released by the universe

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

Which of the following is transferred due to a temperature difference?

• chemical energy

• electrical energy

• mechanical energy

• heat

Tags

NGSS.HS-PS3-4

In an exothermic reaction, the energy stored in the chemical bonds of the reactants is ____.

• equal to the energy stored in the bonds of the products

• greater than the energy stored in the bonds of the products

• less than the energy stored in the bonds of the products

• less than the heat released

Tags

NGSS.HS-PS1-4

The process of converting steam at 125ºC to liquid water at 0ºC requires _____steps on the heating curve calculations.

• five

• four

• three

• two

What does the symbol H stand for?

• the specific heat of a substance

• the heat capacity of a substance

• the heat (enthalpy) of reaction for a chemical change

• one calorie given off by a reaction