19. A typical H2-O2 PEMFC operates at 0.8 V and a fuel utilization of 88% at STP. What is the efficiency of such a fuel cell

Suppose that a certain fortunate person has a net worth of $71.0 billion ($7.10×1010). if her stock has a good year and gains $3.20 billion (3.20×109) in value, what is her new net worth?

Which of these is a density dependent factor? a. epidemic b. earthquake c. drought d. hurricane

6) (a) calculate the absorbance of the solution if its concentration is 0.0278 m and its molar extinction coefficient is 35.9 l/(mol cm). the depth of the cell is 5 mm. (b) what is the %t? (7) calculate the absorbance of the solution if the transmitted light intensity is 70% of the initial light beam intensity