1. Chapter 7: Unit Conversions (Proportion method) If a student weighs 80 kg, how much does he weigh in pounds? Step 1. Find a conversion factor that relates the units of interest to one another (page 34 table). 1 kg ≈ 2.205 pounds

2. Chapter 7: Unit Conversions If a student weighs 80 kg, how much does he weigh in pounds? Step 2. Express the conversion factor as a ratio (fraction): 1 kg 2.205 pounds Chapter 7: Unit Conversions (Proportion method)

3. Chapter 7: Unit Conversions If a student weighs 80 kg, how much does he weigh in pounds? Step 3. Express the problem as a ratio with an unknown: 80 kg ? Chapter 7: Unit Conversions (Proportion method)

4. Chapter 7: Unit Conversions Step 4. Set up a proportion equation such that the units in both numerators are the same and the units in both denominators are the same: 80 kg ? Chapter 7: Unit Conversions (Proportion method) 1 kg 2.205 pounds =

5. Chapter 7: Unit Conversions Step 5. Solve for the unknown: 80 kg (2.205 pounds) Chapter 7: Unit Conversions (Proportion method) 1 kg =? = 176.4 pounds?

6. Chapter 7: Unit Conversions Step 6. Check that the answer makes sense Chapter 7: Unit Conversions (Proportion method) = 176.4 pounds?

7. Chapter 7: Unit Conversions (Unit canceling method) Convert 2.80 kg to pounds. Step 1. Write the problem as an equation. 2.8 kg = ? pounds

8. Chapter 7: Unit Conversions Convert 2.80 kg to pounds. Step 2. Find a conversion factor such that the units cancel (page 34). 1 lb 0.454 kg Chapter 7: Unit Conversions (Unit canceling method)

9. Chapter 7: Unit Conversions Convert 2.80 kg to pounds. Step 3. Place the conversion factor into the equation. 2.80 kg X = ? Chapter 7: Unit Conversions (Unit canceling method) 1 lb 0.454 kg

10. Chapter 7: Unit Conversions Step 4. Solve the equation; multiply 2.80 kg by the conversion factor: Chapter 7: Unit Conversions (Unit canceling method) 2.80 kg X ≈ 6.17 lb 1 lb 0.454 kg

11. Chapter 7: Word Problems Requiring Multiple Steps Transgenic sheep can secrete a human protein, AAT, into their milk. AAT is valuable in the treatment of emphysema. The concentration of AAT in the milk is 15 g/L. A sheep can produce 400 liters of milk each year. AAT is worth $110/gram. What is the value of a year’s production of AAT from such transgenic sheep? = $?/year 400 L year 15 g L X $110 gram X = $660,000/year