SLC Problem Set - 1111111 PDF

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SLC Science Program, Chemistry 1A Fall 2018, Professor Geissler Exam 02 Review, Practice Problem Set https://slc.berkeley.edu/chemistry-1a-1al

Exam 2 Review: Practice Problem Set Question 1: Periodic Trends Please use the molecules below to answer the following questions: Na, Li, Be, C, F, Cl, Cla. Rank these atoms and ions for radius (smallest to largest). b. What trends did you consider and how do these trends affect atomic radius? c. Rank these in the ascending order for electronegativity. d. What trends did you consider and how do these trends affect electronegativity? e. What’s the difference between electronegativity, ionization energy and electron affinity? f. Would Na, or Na+ have a larger ionization energy? Why? g. Show the reaction of NaCl formation. h. What is lattice energy? Question 2: Hybridization Given the molecule H₂BCN: a. Count the total number of valence electrons. b. Draw the Lewis structure. c. Using VSEPR, answer the following questions:

Contributors: Avani Vaid, Naz Dundar, Sneha Agrawal, Valery Yanez, Zhaoyi Gu

Fall 2018

i. ii. iii. iv.

What is the hybridization of B? What is the hybridization of C? What is the hybridization of N? What is the geometry of the central C atom? What is the angle?

d. Draw the 3D representation of H₂BCN. e. What are the bonding and antibonding molecular orbitals present in the BH bonds? Draw an image of what these look like. Question 3: Molecular Orbital Theory A

B

a. Is A or B the correct molecular orbital diagram for F2? b. Label all of the molecular orbitals. c. Fill the molecular orbital diagram for F2 with electrons. d. Is F2 magnetic? e. Draw the Lewis structure of F2. Determine its bond order in terms of the Lewis structure. f. Determine the bond order in terms of the molecular orbital diagram. Is it consistent with the Lewis dot structure? g. Is the bond order for the molecular cation, F 2+ larger or smaller than the bond Contributors: Avani Vaid, Naz Dundar, Sneha Agrawal, Valery Yanez, Zhaoyi Gu

Fall 2018

order of F2? Question 4: Thermodynamics A compound is found to have a molar mass of 284 g/mol, and has a mass composition 43.67% P and 56.33% O. This compound is formed using tetraphosphorus and oxygen gas as follows:

P4 + O2(g) → _______ Additional information: approximate boiling point of the product is 630 K. Use the following atomic masses: P=31, O=16. a. Find the empirical formula and the molecular formula of the compound. b. Add the product to the reaction above and balance the reaction. c. You add 12.4 grams of tetraphosphorus to 64 grams of oxygen gas in a 2 liter jar at 25º C. What is the pressure in the jar before the reaction starts? d. As the reaction takes place, you slowly heat the jar to 400º C. Find the pressure in the jar after the reaction is complete. (hint: don’t forget about the reactants) e. Find the root-mean-square speed of the molecules of the product at this temperature.

Contributors: Avani Vaid, Naz Dundar, Sneha Agrawal, Valery Yanez, Zhaoyi Gu

Fall 2018...