THERMOCHEMISTRY

Calculation questions

100

How many Joules are in 146 calories

What is 611 Joules

200

What is the specific heat of a substance if 1560 calories is required to raise a 312 g sample by 15 degrees Celsius?

What is 0.33 cal/gºC

300

How much energy does it take to convert 750 grams of ice at -15ºC to liquid water at 40ºC?

What is 399 kJ

400

2 KCl + 3 O2 -> 2KClO3 Given that the heat of formation of potassium chloride is -436 kJ/mol and the heat of formation of potassium chlorate is -391 kJ/mol, determine the heats of reaction.

What is 90 kJ

500

A certain mass of water was heated with 41,840 Joules, raising its temperature from 22.0ºC to 28.5ºC. Find the mass of water

What is 1538.46 g

Endothermic and Exothermic

100

A process that releases heat is called

What is exothermic

200

Which process is exothermic the vaporization of water/the freezing of water?

What is the freezing of water

300

What kind of equation is the following reaction: CH4 + O2 -> CO2 + H2O + 1725 kcal

What is exothermic

400

What is an exothermic reaction?

What is a chemical reaction that releases energy

500

What happens to the system in an endothermic process?

What is the system gains heat and the surroundings cool down

Vocabulary

100

This type of energy changes during a phase change

What is potential energy

200

This is the change in energy in a chemical reaction

What is enthalpy

300

A quantity of heat needed to change 1 gram of water by 1 degree Celsius.

What is calorie

400

This is the amount of energy needed to start a reaction

What is activation energy

500

What does it mean if the (delta)H value for a chemical reaction is positive?

What is reactants have less potential energy than products.

Hess's Law

100

If you add 2 or more thermochemical equations to give you a final equation, what does it allow you to do?

What is determine the heat of the reaction directly

200

Cl2(g)+2 HBr(g) -> 2 HCl(g)+Br2(g) (delta)H=

What is (delta)H=-112kJ

300

Find (delta)H: N2H4(l)+H2(g) -> 2NH3(g)

What is (delta)H=-18kJ

400

Find (delta)H: H2SO4(l) -> SO3(g)+H20(g)

What is (delta)H=72.5kJ

500

Find (delta)H: N2H4(l)+CH4O(l) -> CH2O(g)+N2(g)+3H2(g)

What is (delta)H=-46.2kJ

Free For All

100

happed during the phase changes melting, vaporization and sublimation

what is heat get absorbed

200

This occurs when a hot object is placed in contact with a cooler object

What is conduction?

What is heat is transferred from the hot object to the cold object?

300

What is the formula to calculate the amount of heat energy exchanged between the system and its surroundings?

What is q= m c (delta)T

400

If you were to touch a flask in which an endothermic reaction was occurring, the flask would feel _____ before the reaction started.

What is cooler than

500

What amount of heat will be absorbed according to the following equation when 25.0 g of calcium oxide reacts with excess water?  CaO + H2O + 65.2 kJ à Ca(OH)2

what is 29.1 kJ