scin131 Quiz 4 - Questions with 100 Correct Answers | Graded A+

Question 1 of 25 4.0/ 4.0 Points `One of the first chemical WMDs, researchers initially produced VX nerve agent for retail sale in the 1950s as a pesticide. Thankfully, your likelihood of coming in contact with VX is extremely low - the world's stockpiles have been destroyed, including the United States' main stockpile in Anniston, AL. The molecular formula for this nerve agent is C11H26NO2PS, and it has a molar mass of 267.37 g/mol. Given this information, what is its empirical formula?  A. CH2.36N0.09O0.18P0.09S0.09  B. C11H26NO2PS  C. C22H52N2O4P2S2  D. C66H156N6O12P6S6  E. none of these are the correct empirical formula Feedback: Great! Empirical Formula discussed in Chapter 6.2. Question 2 of 25 4.0/ 4.0 Points I was in the lab analyzing compounds from a drug bust and found a compound that had an empirical formula C17H14O7 with a mass of 1321.31 g/mol. What is the value of n (the multiplier) necessary to find the molecular formula?  A. 2  B. 3  C. 7  D. 4  E. 1 Feedback: Great! Empirical Formula discussed in Chapter 6.2. Question 3 of 25 4.0/ 4.0 Points Since 1983, pennies have been made with zinc and plated with copper. Prior to 1983, pennies were about 95% copper and 5% tin and zinc. However, from , pennies were pure copper. If you had a penny from 1800 that had a mass of 2.78g, how many atoms of copper would you have?  A. 6.02 × 1023  B. 1.67 x 1024  C. 8.13 × 10-26  D. 1.19 × 1026  E. 2.63 × 1022 Feedback: Great! Mass percent discussed in Chapter 6.2. Question 4 of 25 4.0/ 4.0 Points `Which of the following is true about a compound's empirical formula?  A. it will always be the same as the molecular formula due to the law of conservation  B. it cannot be reduced to a more simple whole number ratio of elements  C. it is based on the ratios of the masses of each atom present  D. it is unique and no two compounds can have the same emprical formula  E. all of these are true  F. none of these are true Feedback: Great! Empirical Formula discussed in Chapter 6.2. Question 5 of 25 4.0/ 4.0 Points `A chemical known as pyrite is sometimes called Fool's Gold because of it's shiny color. However, it has no gold atoms in it at all! In fact, it's just iron and sulfur atoms at a molar ratio of 1 mole of iron to 2 moles of sulfur. So, using this to determine its chemical formula, what, then, is the %Fe (by mass) in Fool's Gold?