CHEM 131 Midterm Examination APU | Page 2

15 . I recently went to the dentist for a procedure that required me to have laughing gas ( nitrous oxide , or N​ 2​ O ). I specified that I wanted EXACTLY 1.000 x 10​ 25​ molecules of this gas delivered to me . If he was going to be my dentist , he had to prove to me he knew a little chemistry . How many grams would he have to deliver ?
16 . When answering the question of what I would do for a Klondike bar , I said I would jump into the Nile river with a crocodile while wearing 5.50 x 10​ 25​ atoms of lead on my body . What would be the mass of this lead in ​kg ?
17 . I have some aliens in my basement who have developed a chemical weapon in an attempt to escape . I was able to survive the first attack and capture a sample of the dangerous gas . I analyzed it to find that it had a molar mass of 648.52 grams , and its empirical formula is C​ 5​ H​ 11​ N​ 2​ O​ 2​ P . What is its molecular formula ?
18 . In the image below , which reaction type is represented in equation 2 ?
19 . If I ask you to write an equation representing a chemica reaction , you must first know
20 . Oxidation-reduction reactions are also known as redox reactions . We learned about their unique characteristics in this lesson . Which of the following would be a FALSE statement given what we learned about redox reactions ?
21 . You have to be careful about pouring drano down your pipes since it is mainly hydrochloric acid--you can ' t do it if they are made of aluminum because it will dissolve them ! You can ' t acid clean your aluminum auto parts for the same reasons : 2 Al + 6 HCl → 2 AlCl3 + 3H2 . If you were able to dissolve 10.0 mol of Al , how many many moles of hydrogen gas could you make ? NOTE : All numbers located immediately after elemental symbols should be considered subscripts
22 . Suppose you were tasked with producing some nitrogen monoxide ( a . k . a . nitric oxide ). I ' m sure this is often requested of you . You can do it by combusting ammonia ( be careful !). The equation would be as follows : 4NH​ 3​ + 5O ​ 2​ → 4NO + 6H​ 2​ O . If you form 3.50 mol of water , how much NO forms ?