Deriving and Using Ratio Relationships from Statements
Chemistry Unit 5: Chemical Quantities and Calculations
GIA 5-3
Working Mode: Pairs
Reading: Chapter 3
Learning
Objective: To
convert a textual statement into a unit ratio that can be used in solving
problems. To understand density and
percent as well as other mass fraction units as ratios. To understand that the
numerator and denominator of ratios may contain two parts, number and unit or
when dealing with a specific item three parts, number, unit and item.
Instructions:
Express the following relationships as ratio conversion factors. Write
the ratio in both of the ways it can be used.
Identify the parts of the ratio: Underline the number, put a box around
the unit and circle the item.
1.
There are 1,000,000 m in a Megameter.
Student 1:
Identify the equality relationship between m and Mm.
Student 2: Derive both unit ratios
for the m and the Mm.
Student 1: Underline the number
parts of the ratio.
Student 2: Box the unit parts of
the ratio.
2.
One inch has exactly 2.54 cm.
Student
1: Identify the equality
relationship between in and cm.
Student 2: Derive both unit ratios
for the in and the cm.
Student 1: Underline the number
parts of the ratio.
Student 2: Box the unit parts of
the ratio.
Student 2: Determine how many centimeters 7 3/16 inches equals.
3. The tablet contains 45.65% by mass aspirin. Express mass in kg
Student 1: Identify the equality relationship between mass of the aspirin and
mass of the tablet.
Student 2: Derive both unit ratios for the mass of the aspirin and the mass of
the tablet.
Student 1: How many mg of aspirin are in a 325 mg regular aspirin tablet?
Student 2: What mass of tablet must a person take to get 300 mg aspirin?
4. The sea water sample is 6.4 ppm by mass Hg.
Student 1: Identify the equality relationship between mass of the Hg and mass
of the sea water.
Student 2: Derive both unit ratios for the mass of the Hg and the mass of the
sea water.
Student 1: How many mg of Hg are in 1.00 kg of sea water?
Student 2: How much sea water contains 3.2 micrograms of Hg?
3. The density of CCl4 is 1.65 g/mL.
Student 1: Identify the equality relationship between mass of the CCl4
and volume of the CCl4.
Student 2: Derive both unit ratios for the mass of the CCl4 and the
volume of the CCl4.
Student 1: What is the mass of 20.0 mL of CCl4?
Student 2: What volume does 250. g CCl4 occupy?
