I'm a rising senior at Brown studying neuroscience, applying to MD-PhD programs in this AMCAS application cycle. As a premed, I've had fairly rigorous coursework in chemistry, physics, and biology (especially neuroscience). I have had extensive experience preparing for and taking standardized exams, scoring in the 99th percentile or above on the SAT, SAT II subject tests (Math, Biology, Chemistry, Physics, World History), and the MCAT. I also took and received 5's on 17 AP exams spanning a variety of subjects. I'm passionate about mentoring and teaching, and have just completed my second year of TAing Biostatistics, this time as a head TA and a Data Fellow sponsored by the Sheridan Center for Teaching and Learning.
An electron in a hydrogen atom is excited with electrical energy to an excited state with $n=2 .$ The atom then emits a photon. What is the value of $n$ for the electron following the emission?
Write a balanced chemical equation for the combustion of liquid pentane.
Balance the following equations:(a) $\operatorname{Cr}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) \longrightarrow \mathrm{Cr}_{2} \mathrm{O}_{3}(\mathrm{s})$(b) $\mathrm{Cu}_{2} \mathrm{S}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) \longrightarrow \mathrm{Cu}(\mathrm{s})+\mathrm{SO}_{2}(\mathrm{g})$(c) $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{3}(\ell)+\mathrm{O}_{2}(\mathrm{g}) \longrightarrow \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{CO}_{2}(\mathrm{g})$
Balance the following equations and name each reactant and product:(a) $\mathrm{Fe}_{2} \mathrm{O}_{3}(\mathrm{s})+\mathrm{Mg}(\mathrm{s}) \longrightarrow \mathrm{MgO}(\mathrm{s})+\mathrm{Fe}(\mathrm{s})$(b) $\mathrm{AlCl}_{3}(\mathrm{s})+\mathrm{NaOH}(\mathrm{aq}) \longrightarrow \mathrm{Al}(\mathrm{OH})_{3}(\mathrm{s})+\mathrm{NaCl}(\mathrm{aq})$ (c) $\mathrm{NaNO}_{3}(\mathrm{s})+\mathrm{H}_{2} \mathrm{SO}_{4}(\ell) \longrightarrow \mathrm{Na}_{2} \mathrm{SO}_{4}(\mathrm{s})+\mathrm{HNO}_{3}(\ell)$(d) $\mathrm{NiCO}_{3}(\mathrm{s})+\mathrm{HNO}_{3}(\mathrm{aq}) \longrightarrow$$\mathrm{Ni}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\ell)$
Aluminum reacts with oxygen to give aluminum oxide.$$ 4 \mathrm{Al}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{g}) \longrightarrow 2 \mathrm{Al}_{2} \mathrm{O}_{3}(\mathrm{s}) $$ What amount of $\mathrm{O}_{2},$ in moles, is needed for complete reaction with 6.0 mol of Al? What mass of $\mathrm{Al}_{2} \mathrm{O}_{3},$ in grams, can be produced?
Like many metals, aluminum reacts with a halogen to give a metal halide (see Figure 3.1 ).$$ 2 \mathrm{Al}(\mathrm{s})+3 \mathrm{Br}_{2}(\ell) \longrightarrow \mathrm{Al}_{2} \mathrm{Br}_{6}(\mathrm{s}) $$ What mass of $\mathrm{Br}_{2}$, in grams, is required for complete reaction with $2.56 \mathrm{g}$ of Al? What mass of white, solid $\mathrm{Al}_{2} \mathrm{Br}_{6}$ is expected?
