DE Semester 2 Review So far!)

For the formula:
 Q= m c ∆T
The  units for specific heat are:

• g /J C
• °C/g J
• kJ/g
• J/g°C

What would be the effect on the particles if more heat is supplied to the system?

• They would slow down
• They would stop moving
• They would speed up
• There would be no effect

If two objects have different temperatures when they come in contact, heat will flow from the warmer object to the cooler one UNTIL ____________

• one reaches a temperature of zero

• they both have an equal temperature

• one runs out of energy

What is the specific heat of an unknown substance if 100.0 g of it at 200.0 °C reaches an equilibrium temperature of 27.1 °C when it comes in contact with a calorimeter of water.  The water weighs 75. g and had an initial temperature of 20.00 °C?  (Specific heat of water is 4.18 J/g°C) (show your work)

• 0.111 J/g°C
• 1.29 J/g°C
• 0.129 J/g°C
• 22225.85 J

For a skillet, used for cooking, do you want a high or low specific heat

• High, so that it will need more energy to heat up

• Low, so that it will change temperature quickly

In an exothermic process, the surroundings are gaining energy.

• True
• False

What is a tool that measures the heat of chemical reactions?

• calorimeter
•  calorie
• Styrofoam™ cup
• none of these

A metal cube at temperature of 10°C immersed in a liquid at temperature of 70°C.
What is the temperature of the metal cube when thermal equilibrium is achieved between the cube and the liquid?

• Between 10°C and 70°C
• More than 70°C
• Less than 10°C
• Same as the room temperature

The enthalpies of combustion of C(s), H2(g) and C4H9OH(l) (in kJmol^-1) are as follows  
C(s) + O₂(g)   ->  CO₂(g)                                               ∆H=a
H₂(g) + ½O₂(g)   ->   H₂O(l)                                        ∆H=b
C₄H₉OH(l) + 6O₂(g)   ->   4CO₂(g) + 5H₂O(l)  ∆H=c
What is the enthalpy change for the reaction shown below?
  4C(g) + 5H₂(l) + ½O₂(g)   ->   C₄H₉OH(l)

• c – 4a – 5b
• 2a + 10b - c
• 4a + 5b - c
• 2a + 5b + c

The standard enthalpy changes of combustion of carbon, hydrogen and methane are shown in the table. 
Which one of the following expressions gives the correct value for the standard enthalpy change of formation of methane in kJ mol^–1?
C(s) + 2H₂(g) → CH₄(g) 

• 394 + (2 × 286) – 891 
• –394 – (2 × 286) + 891 
• 394 + 286 – 891 
• –394 – 286 + 891