QUIZ ANSWER KEY

1. If the atoms of an object are moving or vibrating fast, the temperature of the object would be Hot.

2. The fact that desert sand is very hot in the day and very cold at night is evidence that sand has a low specific heat.

3.Heat energy travels from an object with a high?

Both of these, for they say essentially say the same thing

4.A surveyor uses a steel measuring tape that is exactly 50m at a temperature of 20 °C. What is the length of steel measuring tape in a hot summer day when the temperature is 35 °C? when (αsteel = 1.2×10-5/°C)      

ΔL= LαΔT                                                L=ΔL+L0

ΔL= (5m)(1.2x10-5/°C)(35°C-20°C)         L=0.009m+50m

ΔL= 0.009m                                             L=50.009m

5. Two matters have specific heat capacities c and 2c. If we give Q and 4Q heat to these matters, changes in the temperatures of them become equal. If the matter A has mass m, find the mass of matter B in terms of m.

Q=m.c.ΔT

Q=mA.c.ΔT           4Q=mB.2c.ΔT

mB=2mA

mB=2m

6. A gas in a closed container is heated with 50J of energy, causing the lid of the container to rise. If the change in energy of the system is , how much work was done by the system?

ΔEint = ΔU=Q−W

           30J=50J−W 

         −20J=−W

7. Which of the following represents the first law of thermodynamics?

The first law of thermodynamics is another wording of the law of conservation of energy. Effectively it states that energy cannot be created or destroyed, but it can change forms.

This means that, in the given situation of the ball rolling down the hill, the total initial energy equals the final kinetic energy plus heat. 

8. When 100 kJ of work is done on a closed system during a 

process, the total energy of the system increases by 55.0 kJ. 

Calculate how much heat is either added or removed from

the system?

ΔEint = ΔU=Q−W

               Q=ΔU−W

               Q=55J−100

               Q=-45KJ

9. A gas start with 200J of internal energy, While you add 180J of Heat to the gas, The gas does 70J of work. What would be the final internal energy of the gas?

            ΔU = Q−W

         Uf-Ui = Q−W

    Uf-(200) = 180J - 70J

             Uf = 110J + 200J

             Uf = 310 J

10.The absolute thermodynamic temperature scale is also known as Kelvin scale.

PREVIOUS