Unit 7: Thermochemistry

Heat is...

• The transfer of thermal energy between two bodies that are a different temperature.

• A unit of measurement, form of energy and a physical property

• A physical property with twice the amount of value than that of a temperatures source

• A type of matter in which the objects can be perceived as absract

what does n mean in the following equation? △H°rxn = ⨊n (△H°f) of products - ⨊n (△H°f) of reactants

• Number of moles

• number of atoms

• number of ionic configurations

• type of compound used in the formula

What are the correct units for the specific heat equation?

• J = s x J/L°C

• J/g°C + D = J

• F = Q x J/m°C

• J = g x J/g°C x °C

Solve the following problem using:

△H = -3013 KJ

1 mole of P₄ reacts, 3013 KJ of heat will be RELEASED. How much heat will be released if 230 g of P₄ reacts?

Remember to use the coeff. in the equations.

Answer explanation

Use dimensional analysis to figure it out

The --- of a substance is the amount of heat required to raise the temperature of 1g of the substance by 1℃.

Temperate is the measure of ...

• Degree of brightness or darkness in relation to wavelegths

• Degree of wetness or dryness
• The thermal energy

  *Temp. does NOT equal thermal energy*

• Degree of loudness or quietness according to solubility

True or False: phase changes occur without a change in temperature, rather heat.

• False

• True

What do these letters stand for? Q = m x s x △T

• Change in Heat = mass x specific heat x change in temperature

• Quantity = mass x specific heat capacity x change in pressure

• Quantity = mass x specific heat capacity x time

• Quantity = mass x specific heat capacity x temperature

What do thermochemical equations show?

• How much heat is absorbed or released during the reaction.

• The stoichiometry of reactants and products in a chemical reaction.
• The rate at which a chemical reaction occurs.
• The physical properties of reactants and products in a chemical reaction.

If you --- both sides of the equation by a factor n, then △H must change by the --- factor.