Calculation questions
Endothermic and Exothermic
Vocabulary
Hess's Law
Free For All
100

How many Joules are in 146 calories (conversion is famous number for water's specific heat)

What is 610 Joules

100
A process that absorbs heat is called
What is endothermic
100

What happens to energy when is moves from one system to another

What is energy is conserved OR heat in equals heat out (q=-q)

100

Add 2 or more thermochemical equations to give you a final equation

What is the heat of the reaction (or Hess' Law)

100

What happens to the water in a calorimeter when an exothermic reaction occurs in it

What is absorbs heat, and a rise in temperature.

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

200
Which process is exothermic the vaporization of water/the freezing of water?
What is the freezing of water
200

Name of the energy released or absorbed when a solid dissolves.

What is heat of solution

200

The Delta H for the reaction:  Cl2 (g)+ H2 (g) -> 2 HCl (g)   (H-Cl = 431 kJ/mol,  H-H = 436 kJ,  Cl-Cl = 243 kJ/mol)

What is (delta)H=-183 kJ/mol

200

Why does warm water have a more rapid of evaporation than cold water?

What is Its molecules have a higher average kinetic energy.

300

How much energy does it take to convert 750 grams of ice at -15ºC to liquid water at 40ºC? (H fusion = 333 J/g; c (ice)= 2.1 J/goC; c (water)= 4.18 J/goC)

What is 399 kJ

300
What kind of equation is the following reaction: CH4 + O2 -> CO2 + H2O + 1725 kcal
What is exothermic
300

A quantity of heat needed to change 1 gram of water by 1 degree Celsius (or 4.18 Joules).

What is a calorie?

300

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

Hf of N2H4 = +50.6 kJ/mol   and  Hf of NH3 = -46.2 kJ/mol

What is (delta)H=-143 kJ

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

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

What is 90 kJ

400
What is an exothermic reaction?
What is a chemical reaction that releases energy
400

When dissolving is exothermic

Solute-solvent bonds are greater than solute-solute and solvent-solvent bonds.

400

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

       Hf =         -811.3        -395.2     -241.8

What is (delta)H= + 174.3 kJ

400

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

What is cooler

500

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

What is 1540 g

500
What happens to the system in an endothermic process?
What is the system gains heat and the surroundings cool down
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.

500

Find (delta)H:    CS2(ℓ) + 3O2(g) ---> CO2(g) + 2SO2(g)

Given:   C(s) + O2(g) ---> CO2(g)   ΔH = −393.5 kJ/mol

             S(s) + O2(g) ---> SO2(g)   ΔH = −296.8 kJ/mol

             C(s) + 2S(s) ---> CS2(ℓ)     ΔH = +87.9 kJ/mol

What is (delta)H= -1075 kJ

500

What determines the amount of temperature change due to a chemical reaction?

What is the mass and amount of heat released or absorbed by the reaction

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