4. Evaluate the following expression and report your answer to the proper number of significant figures: 245.1 g - 241.50 g 1.56 mL 6. A leaky faucet drips water at the rate of 1 drop every 2 seconds (exactly). Assuming 20 drops = 1 mL (exactly), how many days would it take to leak 500 ft of water? For answer: 7. The element californium (Ct) sells for $1000 per ug. Assuming 6.02 x 102 atoms of Cf have a mass of 251 grams, how many atoms of Cf could you buy for 1 U.S. penny? answer: 8. A person on a diet reduces from 554 pounds to 152 bounds in exactly 14 months. Calculate the average rate of "weight" loss in units of mg/see. [You may assume that 1 month - 30 days, exactly.)