conversion practice - Head

MORE CONVERSION PRACTICE
name_____________ date____
Use Dimensional analysis. Show ALL your work. Every number needs a unit!
1. The density of ice is 0.93 g/mL.
You have an ice block which has a volume of
300mL. (a) What mass of ice is this?
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(b) What volume will it occupy as water? (Density of water is 1g/cm )
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(c) write a ratio for the conversion of mL and cm .
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2. The density of osmium is 22.59g/cm .
Osmiroid pen nibs, contained osmium because it is a very hard
metal and wears well. Osmium was found to be very toxic, so
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no longer used in nibs! Each nib contained 4.3 x 10
g.
(a) What volume of Osmium is this?
(b) Osmium costs about $13000/Kg. What is the cost of the osmium in the pen nib?
3.
Demo:
Draw diagrams of the two beakers on the trolley and label
CALORIMETRY problems:
substance
Cu
Ag
Au
Pb
water
Fe
specific heat J/g°C
0.386 0.235
0.126
0.128
4.18
0.450
1. How much energy is lost when 68.9g of solid gold cools from 455°C to 35°C?
2. What is the mass of a piece of silver if absorbing 97,000J of energy causes a 46.5°C
temperature change?
3. What is the specific heat of an unknown substance if 386.6g of it absorb 4500J and
have a temperature change of 6.8°C?
4. What mass of water will have a temperature change from 25°C to 100°C if one had
570 Kcal? (the amount of energy in a large order of McDonald’s French Fries.)
Answer the rest on binder paper along with the dimensional analysis problems:
5. You have 340 g of each of these metals at room temperature (22°C)
A. gold
B. copper
C. iron
a. How many joules are required to raise each sample’s temperature to 100°C.
b. Which sample requires the most energy to heat to 100°C?
c. Which sample has the lowest specific heat?
d. If you allowed the heated samples to cool back down to room temperature (22°C),
how many joules would each sample release. Show reasoning.
e. If you drop each heated sample into 200 g of room temperature water, which
sample will heat the water the most? Show reasoning.
Going further:
1. Suppose a 47.6 g piece of metal with a temperature of 100°C is dropped into
100.0 g of water at 24°C. The final temperature of the system is 32.5°C. What is
the specific heat of the metal?
2. A blacksmith heated an iron bar to 1445°C. The blacksmith then tempered the
metal by dropping it into 42.8 liters of water that had a temperature of 22°C.
The final temperature of the water was 45°C. What is the mass of the iron bar?