Download WORKSHOP 2: Dimensional Analysis and

WORKSHOP 2: Dimensional Analysis and Energy
Answer Key
Show your calculation setup for the following problems. Make certain to express the
appropriate units and round-off your answers to the proper number of significant figures.
You will need to look-up certain conversion factors in your course guide and textbook.
1. Convert 25 oF to degrees Celsius.
-4 oC
2. Convert -75 oC to degrees Fahrenheit.
-103 oF
3. A ruler is 48.0 in. long. How long is this in centimeters?
122 cm
4. A bowling ball weights 15.3 lbs. Calculate its mass in grams.
6.95 x 103 g
5. 125 mL of water are contained in a beaker. Convert this to quarts.
1.32 x 10-1 qt
6. An object has a mass of 35.8 g and a volume of 40.5 cm3. Calculate the density of the
object in g/mL.
0.884 g/cm3
7. A rubber stopper weighing 65.4 g is immersed into a graduated cylinder filled with
30.0 mL of liquid. The liquid level then rises to 48.8 mL. Calculate the density of
the stopper.
3.48 g/mL
8. If the density of a liquid is known to be 0.785 g/mL, calculate the mass of the liquid if
its volume is 18.8 mL.
14.8 g
9. Given the table of specific heat values below, what is the identity of a 26.2 g metal
sample that increases by 8.5 ºC when 100.0 J of energy is absorbed? Use the
formula q = m s ∆T and solve for specific heat. In other words,
100.0 J = (26.2 g)(s)(8.5 °C). Once you solve for s, match the value with the
metal below which is Fe.
Element
Au
Ag
Cu
Fe
Al
Specific Heat (J/g ºC)
0.128
0.235
0.385
0.449
0.903
10. Determine the final temperature (in ºC) of 245 mL of water initially at
32 ºC upon absorption of 17 kJ of heat. Recall we learned that the density of water
is approximately 1 g/mL. Therefore, that means that 245 mL = 245 g water.
Therefore, solve for the final temperature via q = m s (Tfinal - Tinitial) to obtain
Tfinal = 49 oC.