Show your work for 2 points each. How many moles of Pb is 9.3 × 10 15atoms of Pb?

2. What is the molar mass of ethane, C2H6?

3. Find the mass of 3.65 × 10 -2mol K2SO4.

4. How many representative particles are in 2.5 mol H2O2?

5. What is the molar mass of Al2(SO4)3 ?

6. How many moles is 112 g of oxygen gas (O2) ?

In a laboratory experiment, a fermenting aqueous solution of glucose and yeast produces carbon dioxide gas and ethanol. the solution was heated by burning natural gas in a bunsen burner to distill the ethanol that formed in the flask. during the distillation, the ethanol evaporated and then condensed in the receiving flask. the flame of the burner was kept too close to the bottom of the flask and some of the glucose decomposed into a black carbon deposit on the inside of the flask. during this experiment the following changes occurred. which of these changes involved a physical change and not a chemical change? check all that apply. 1-condensation of ethanol 2-evaporation of ethanol 3- formation of carbon dioxide gas from glucose burning of natural gas 4-formation of ethanol from glucose by yeast 5-formation of a carbon deposit inside the flask

Answer explain why it is not possible to deduce a complete order of reactivity.

State one important difference between a physical change and a chemical change?