R1 IB Chem

What is the property that is commonly measured when observing thermal energy (heat) changes.

temperature

An ice cube is placed into a glass of water. The liquid water in the glass decreases in temperature. In this process, energy is being transferred from the ___ to the ___

water, ice cube

Which shows the change in temperature, in K, when a sample at 25 °C increases to 50 °C?

25K

Energy can exist in various forms, like ___

Kinetic

(___) is transformed from one form to another

Energy

When a substance transitions from a solid to a liquid, energy is ___

Absorbed

Temperature is used to measure changes in ___ energy (heat).

Thermal

(___) reactions involve the formation of a new substance and involve changes in energy.

Chemical

Chemical reactions involve the formation of a new ___ and involve changes in energy.

Substance

What is energy?

The ability to do work or cause a change

What is the unit used for energy

joules (J)

What are the 3 types of energy transfer?

Conduction, convection, and radiation

What is conduction

the transfer of energy by direct contact

What is convection

the transfer of energy by the movement of fluids

What is radiation

the transfer of energy by electromagnetic waves

What is chemical potential energy?

It’s stored in the bonds of the reactants

What is temperature?

It’s a quantitative measurement often associated with heat. It’s a measure of the average kinetic energy of particles

What is heat?

It’s the energy transferred from a region of high temperature to a region of low temperature

What are the units used for temperature?

C and K

What are the units used for heat

J

Which describes exothermic reaction?

System releases energy to the surroundings. Surroundings feel warm to the touch

Which describes endothermic reaction?

System absorbs energy from surroundings. Surroundings feel cool to touch

Which changes of state are endothermic?

Evaporation, sublimation, melting

Which changes of state are exothermic

Condensation, deposition, freezing

Which reaction is energy released?

exothermic

Which reaction is energy absorbed

endothermic

In endothermic reactions, ___ are more stable

reactants

In exothermic reactions, ___ are more stable

reactants

What is the equation for thermal energy?

Q=(m)(change in T)(c )

What is Q in the equation for thermal energy?

Thermal energy. Units of joules (j)

What is c in the equation for thermal energy?

specific heat capacity (specific to the substance undergoing a change in temperature). Units of joules per gram per unit Kelvin

what is m in the equation for thermal energy?

mass (of the species you’re measuring the change of temperature of). Units of grams (g)

What is the equation for change in enthalpy?

change in H=-Q/n

What is change in H in the equation for change in enthalpy?

Change in enthalpy. Units in kilojoules/mol (kJ/mol)

What is Q in the equation for change in enthalpy?

Thermal energy (heat absorbed or released). Units in joules (J)

What is n in the equation for change in enthalpy?

number of moles of an identified reactant or product in the chemical reaction. Units in moles (mol).

The standard enthalpy change for a chemical reaction refers to

heat transferred at constant pressure under standard conditions and states

Monitoring temperature changes during chemical reactions allows for

calculation of thermal energy transfer and enthalpy change

(___)is the average kinetic energy of particles in a system

Temperature

(___) is energy transferred from a region of high temperature to a region of low temperature

Heat

Exothermic reactions involve a transfer of energy from the system to the ___

surroundings

Exothermic reactions involve a transfer of energy from the ___ to the surroundings

system

Endothermic reactions involve a transfer of energy from the ___ to the system

surroundings

Endothermic reactions involve a transfer of energy from the surroundings to the ___

system

(___) reactions have products with a higher relative stability than reactants

Exothermic

(___) reactions have reactants with a higher relative stability than products

Endothermic

Energy profile diagrams have labels of reaction coordinate on the x-axis and ___ on the y-axis

potential energy

Energy profile diagrams have labels of ___ on the x-axis and potential energy on the y-axis

reaction coordinate

The standard enthalpy change for a chemical reaction refers to the heat transferred at constant pressure under ___ and states

standard conditions

The standard ___ for a chemical reaction refers to the heat transferred at constant pressure under standard conditions and states

enthalpy change

The enthalpy change of reaction can be determined from the ___

change in temperature