1. For the element potassium, K: (a) Calculate the number of moles in 7.09 g. (b) Calculate the number of grams in 0.237 mol.

(c) How many moles are there in 9.04 x 10^22 atoms of the element?

2. Answer the following questions about the compound C10H6Cl2. Report your answers to parts (a)-(c) 2 decimal places.

(a) What is the molar mass (g/mol). (b) What is the percentage carbon? (c) What is the percentage hydrogen? (d) How many atoms of carbon are contained in 1.00 g of the compound? Report your answer scientific notation to 3 significant figures.