Practice_EXAM_I

According to this proportion or ratio 5500 mole of

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Unformatted text preview: al formula is CH3 and the empirical molar mass of CH3 = 12x1+1x3 =15. So the integer = 30/15 = 2. Thus there are two empirical formulas in a molecular formula. Therefore, the molecular formula is C2H6. 21. What are the coefficients respectively when the equation __PH3 + __O2 __P2O5 + __H2O is balanced? (a) 2, 2, 1, 3 (b) 2, 1, 3, 4 (c) 2, 3, 1, 2 (d) 2, 4, 1, 3 (e) 1, 1, 3, 3 Hint: For 11th ed.: 90‐95 and Example 3.12; For 9th edition: p.p. 94‐97. Example 3.12 or p. 109 (3.60). 10th edition: p.p. 94‐99: Example 3.12. Balancing an equation is a process of trial an error. Sometimes it requires more than one trial. Usually start visual examination and select the most bulky species, that is, the one with the most different kinds of atoms and number of atoms as the reference and set its coefficient as one. In this question, P2O5 is the most bulky one, we put 1 in front of it to remind us we have done examining P2O5. Now the equation is updated to __PH3 + __O2 1 P2O5 + __H2O 4 Since P2O5 contains 2 phosphorus atoms, so we need two phosphorus atoms at the left s...
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This note was uploaded on 01/25/2014 for the course CHEM 1411 taught by Professor None during the Fall '11 term at HCCS.

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