1.16 Unit Test Chemical Thermodynamics

Question: Unless otherwise instructed, you may use a scientific calculator and refer to the periodic table in the Chemistry: Problems and Solutions book for this question.

Which example is an exothermic reaction?

Answer: condensation

Question: Two objects (A and B) of the same temperature are in contact with each other.

Which statement is true?

Answer: Although the molecules collide, no heat transfers because there is no temperature difference between the objects.

Question: Which parameter is measured directly in a coffee-cup calorimeter?

Answer: temperature

Question: Which type of substance would be best for use in a heating system?

Answer: a liquid with a high specific heat

Question: The reaction 2NO(g) → N2(g) + O2(g) has a ΔH=−180.5kJ .

How much heat will be required to produce 44.8 L of NO by the reverse reaction?

Answer: 180.5 kJ

Question: Which statement is true?

Answer: In an exothermic reaction, the energy of the products is less than the energy of the reactants.

Question: Which statement is a correctly written thermochemical equation?

Answer: 4Fe(s)+3O2(g)→2Fe2O3(s), ΔH=−3,926kJ

Question: What is likely to be true about the ΔH for this reaction?

C6H6 (s) → C6H6 (l)

Answer: ∆H>0

Question: Two hundred grams of a substance requires 0.52 kJ of heat to raise its temperature from 25°C to 45°C.

Use the table to identify the substance.

q=mCΔT.

Mass (m) is in grams. Temperature is in degrees Celsius.

Picture of Graph included.

Answer: gold

Question: A chemical reaction is carried out in a closed container. The energy absorbed by the chemical reaction is 200 kJ.

What is the energy liberated from the air or the walls of the container?

Answer: 200 kJ