Chemistry Exam 1 Practice

Exam 1 Practice

• The average score on the exam was 72%
• Students should treat this practice exam like a real exam and time themselves for 50 minutes
• Only a calculator and a periodic table and formula sheet are allowed
• Use pencil, write legibly, and show all work and calculations
• Answers without accompanying work receive zero points
• Report answers with the correct units and significant figures
• Clarification questions are allowed, but no help with questions
• Any corrections to the exam will be written on the board and announced
• Scratch work should be done on the back page and clearly labeled
• The honor code requires students to acknowledge that they have not given or received any assistance on the exam

Molecular Formulas and Names

• Na2Se: Sodium Selenide
• Nickel (II) Carbonate: NiCO3
• Dinitrogen Trioxide: N2O3
• (NH4)3P: Ammonium Phosphide
• Pb(CrO4)2: Lead (II) Chromate

Calcium Arsenate

• The formula for Calcium Arsenate is Ca3(AsO4)2
• The arsenate ion is polar
• The most stable resonance structure for the arsenate ion is the one with the negative charges on the oxygen atoms that are not double bonded to the phosphorus

Molecular Geometry

• The molecular geometry around phosphorus is tetrahedral
• The C-O-C angle is larger than the H-P-H angle
• The electron geometry around the nitrogen is tetrahedral
• The N-H bond is the longest bond on average
• The hybridization around the carbon marked with an arrow is sp3
• The N - H bond is formed by the overlap of an sp3 and an s orbital
• The C - C bond is formed by the overlap of an sp3 and an sp3 orbital
• Four unhybridized p orbitals are used for bonding in this molecule

SNCl2+

• The Lewis structure for SNCl2+ has 26 valence electrons
• There is a formal charge of +1 on the sulfur atom and a formal charge of -1 on one chlorine atom

Br 4At

• The VSEPR-3D model shows the bromine atoms in a square planar arrangement around the astatine
• The electron geometry around the astatine is square planar
• The molecular geometry around the astatine is square planar
• The bond angles around astatine are 90 degrees
• The molecule is nonpolar

Phosphorus and Chlorine Molecule

• There is a formal charge of +1 on the phosphorus atom and a formal charge of -1 on one chlorine atom
• The phosphorus atom has a tetrahedral molecular geometry
• The molecule is polar

Intermolecular Forces

• Hydrogen bonding and dipole-dipole forces are present between molecules with hydrogen bonding (like water)
• Dipole-dipole forces are present between polar molecules
• London dispersion forces are present between all molecules

Polarity

• Both Molecule A and Molecule B are polar

Nitrogen Molecule

• There are 5 sigma bonds in the given structure
• There are 2 pi bonds in the given structure
• The electron geometry around nitrogen is trigonal planar
• The resonance structure that accounts for the trigonal planar geometry around the nitrogen atom shows a double bond between the nitrogen and one of the oxygens, a single bond between the nitrogen and the other oxygen, and a lone pair on the positively charged nitrogen

Prepare for your Chemistry Exam 1 with this practice quiz that mimics the exam conditions. Covering key topics such as molecular formulas and naming compounds, this quiz is designed to enhance your understanding and performance. Remember to time yourself and show all work for complete credit.