Chemistry Questions and Answers

For each atom in the table below, write down the subshell from which an electron would have to be removed to make a +1 cation and the subshell to which an electron would have to be added to make a -1 anion. The first row has been completed for you. | Atom | Subshell from which electron removed to form +1 cation | Subshell to which electron added to form -1 anion | | --- | --- | --- | | H | 1s | 1s | | Hg | | | | Ne | | | | K | | |

Ozone, O_{3}, is not a linear molecule. It is bent with an angle that is a little less than 120°. a. Draw the Lewis structure of ozone, O_{3}. b. Describe why ozone has a bent shape instead of a linear shape. c. Describe why ozone's bond angle is larger than that of water, H_{2}O.

If a compound is reduced, what is the result? Fewer C-H bonds Increased number of C-H bonds Fewer C-Z bonds Both increased number of C-H bonds and fewer C-Z bonds Which of the following terms explain why aldehydes are more reactive than ketones? $\bigcirc$ Hybridization and resonance $\bigcirc$ Electronegativity and resonance $\bigcirc$ Electronegativity and hybridization $\bigcirc$ Sterics and electronics Which reagent can be used to reduce the carbonyl in methyl vinyl ketone? $\mathrm{NaH}$ $\mathrm{FeCl}_{3}$ $\mathrm{NaBH}_{4} / \mathrm{CH}_{3} \mathrm{OH}$ $\mathrm{H}_{2}$ and Pd-C What reagent would be used to reduce an amide to an amine? - NaBH₄ - LiAlH(OtBu)₃ - FeCl₃ - LiAlH₄ What is the name of the general reaction type that carboxylic acids, esters, and amides undergo? - Nucleophilic acyl addition - Electrophilic acyl substitution - Nucleophilic acyl substitution - Electrophilic acyl addition

What is the molecular geometry of NF3? A. Trigonal pyramidal B. Tetrahedral C. Trigonal planar D. Bent

Which of the following best defines Avogadro's number? A. Mass, in grams, of each particle of the substance B. Number of particles in one mole of a pure substance C. Mass, in grams, of the nucleus of the substance's atoms D. Total mass, in grams, of all the particles in one mole of the substance

Is sulfur a metal or a nonmetal? How many valence electrons does a sulfur atom have?

Is calcium a metal, non-metal, or metalloid? Show your work.

What is the molar mass of fluorine gas, F 2 ?

# 14) Anson -1) neutral D) radical E) They are all the same size. 14) Mostlly the elements correctly shown by decreasing radii size. A) $\mathrm{N} 2-\mathrm{N}$ B) $\mathrm{K}=\mathrm{N}$ C) $\mathrm{N}>\mathrm{N} 3$ D) $\mathrm{C} 12+\mathrm{Cs}$ E) $\mathrm{S}->82$

How do you find the van't Hoff factor?

Fill in the subshell from which the electron is removed to form a +1 cation and the subshell to which the electron is added to form a -1 anion. Atom Subshellfromwhichelectronisremovedtoform+1cation Subshell to which electron is added to form -1 anion H 1s 1s Y □ □ Ga □ □ Ca □ □

How many valence electrons does lithium (Li) have available for bonding? A. 1 B. 2 C. 3 D. 4

Draw the Lewis structure for acetylene (C2H2). Be certain you include any lone pairs.

# 2 Question Use the periodic table $\varnothing$ to write the electron configuration of gallium (Ga). Drag the labels to the correct locations on the image. Each label can be used more than once.

The formal charge is the "charge" an element would have in a molecule or ion if all of the bonding electrons were shared equally between atoms. We can draw three inequivalent Lewis structures for the thiocyanate ion, $S C N^{-}$. The concepts of formal charge and electronegativity can help us choose the structure that is the best representation. 1. Assign formal charges to the elements in each of the structures below. | | Formal Charge | | --- | --- | | A | | | B | | | C | | | SCN- | $+10-1$ | | | $00-1$ | | | $0-10$ | 1. The best Lewis structure for $S C N^{-}$is $\qquad$ .

Write the name of each polyatomic ion: NO3-

# 2 Which best describes a stable binary ionic compound? (2 Points) two ions with the same charges and a net charge of negative one two ions with opposite charges and a net charge of positive one two ions with the same charge and a net charge of zero (0) two ions with opposite charges and a net charge of zero (0)

What is the Lewis structure of a fluorine molecule $\left(\mathrm{F}_{2}\right)$ ?

Why is propylene glycol banned in Europe?

Re-order each list in the table below, if necessary, so that the atoms or ions in it are listed in order of decreasing size. | atoms or ions | atoms or ions in order of decreasing size | | --- | --- | | Be, Be⁺, Li | Li, Be, Be⁺ | | Br, I, Cl | I, Br, Cl | | Cl, Na, S | ☐, ☐, ☐ | ☐ ☐ ☐ ☑ ☐ ☐ ☒ ☑

Explain how to calculate an Rf value and what that information can tell you about the success of your reaction. Was your guaifenesin synthesis successful?

# Draw the Lewis structure for chloroform, $\mathrm{CHCl}_{3}$. What are the electron pair and molecular geometries?

"Draw a diagram that connects substrates and products of photosynthesis and cellular respiration (CO₂, O₂, H₂O, etc.). Which of these processes is (are) performed by microalgae? By aerobic bacteria?"

"There are 6 strong acids you need to know. List their names and formulas below: Names of Acids: Acid 1 Acid 2 Acid 3 Acid 4 Acid 5 Acid 6 Formulas: Formula 1 Formula 2 Formula 3 Formula 4 Formula 5 Formula 6 Classify each of the following as a strong acid or a weak acid. Indicate how each should be written in aqueous solution. For example, should hydrochloric acid (HCl) be written as HCl or as H+ + Cl−? Phosphoric acid: In solution, this acid should be written as __________. Nitrous acid: In solution, this acid should be written as __________. Hydrofluoric acid: In solution, this acid should be written as __________."

Describe the difference between hypochlorous acid and hydrochloric acid.

How many valence electrons do barium and phosphorus have, respectively?

Atoms will combine with each in order to become more chemically stable. Compounds are formed between two atoms that have | | | | --- | --- | | | | outer energy levels. The two types of compounds that can be formed between atoms are ionic and covalent. Ionic compounds are formed between two charged atoms. Ionic compounds contain a ion and a nonmetal ion. Metals will lose electrons to form positive ions and nonmetals will gain electrons to form negative ions. These oppositely charge ions are very attracted to each other and form very strong bonds as a result. Ionic compounds are characterized by crystalline structure, | | | | --- | --- | | | | melting and boiling points, and are at room temperature. Two will combine to form covalent compounds. Covalent compounds are formed when two atoms | | | | --- | --- | | | | one or more pairs of electrons. The force of attraction between the nonmetals is relatively weak. Covalent compounds are characterized by | | | | --- | --- | | | | melting and boiling points and can be gases, liquids, or soft solids at room temperature. | | | | --- | --- | | | | metal | oppositely | incomplete | low | share | nonmetals | solids | high

Show how lithium forms an ion. Does it form a cation or an anion?

The molar mass of carbon dioxide (CO2) is _____. A. 44.0 g/mol B. 47.0 g/mol C. 43.0 g/mol D. 42.5 g/mol

# **Experiment 23** ## **Advance Study Assignment: Determination of the Equilibrium Constant for a Chemical Reaction** 1. A student mixes 5.00 mL 2.00 × 10^-3 M Fe(NO₃)₃ in 1 M HNO₃ with 3.00 mL 2.00 × 10^-3 M KSCN and 2.00 mL of water. She finds that in the equilibrium mixture the concentration of FeSCN²⁺ is 7.0 × 10^-5 M. Find *K* for the reaction Fe²⁺(aq) + SCN^-(aq) with Fe(SCN)²⁺(aq). **Step 1** Find the number of moles Fe²⁺ and SCN^- initially present. (Use Eq. 3.) $$ \begin{aligned} 2.00 \times 10^{-3} \, \text{mM} & \times 0.005L + 1.00 \times 10^{-2} \, \text{mM} \\ 1L & \times 0.005L + 4.00 \times 10^{-2} \, \text{mM} & \times 3.10^{-2} \, \text{moles Fe}^{2+} \\ 10.00 \, \text{mL} & \times 0.005L + 7.00 \times 10^{-3} \, \text{mM} & \times 3.10^{-2} \, \text{moles Fe}^{2+} \\ 10.00 \, \text{mL} & \times 4.00^{-2} \, \text{moles FeSCN}^{2+} \end{aligned} $$ **Step 2** How many moles of FeSCN²⁺ are in the mixture at equilibrium? What is the volume of the equilibrium mixture? (Use Eq. 3.) $$ \begin{aligned} 2.00 \times 10^{-3} \, \text{mM} & \times 0.005L + 7.00 \times 10^{-3} \, \text{mM} \\ 1L & \times 0.005L + 4.00 \times 10^{-3} \, \text{mM} \\ 10.00 \, \text{mL} & \times 3.10^{-2} \, \text{moles FeSCN}^{2+} \end{aligned} $$ How many moles of Fe²⁺ and SCN^- are used up in making the FeSCN²⁺? $$ \begin{aligned} 8 \, \text{mM} \, \text{Fe}^{2+} + \text{SCN}^{2+} & + 7.00 \times 10^{-3} \, \text{mM} \\ 7.00 \, \text{mM} & + 7.00 \times 10^{-3} \, \text{mM} \\ 7.00 \, \text{moles Fe}^{2+} & + 7.00 \times 10^{-3} \, \text{moles SCN}^{2+} \end{aligned} $$ **Step 3** How many moles of Fe²⁺ and SCN^- remain in the solution at equilibrium? (Use Eq. 4 and the results of Steps 1 and 2.) $$ \begin{aligned} (1.00 \times 10^{-5} - 7.00 \times 10^{-5}) & = 7.00 \times 10^{-4} \, \text{mM} \\ (4.00 \times 10^{-4} - 7.00 \times 10^{-5}) & = 5.30 \times 10^{-4} \, \text{mM} \\ 1.00 \times 10^{-4} & = 5.30 \times 10^{-4} \, \text{moles Fe}^{2+} \\ 1.00 \times 10^{-4} & = 5.30 \times 10^{-4} \, \text{moles SCN}^{2+} \end{aligned} $$ **Step 4** What are the concentrations of Fe²⁺, SCN^-, and FeSCN²⁺ at equilibrium? (Use Eq. 3 and the results of Step 2 and Step 3.) $$ \begin{aligned} 9.30 \times 10^{-2} & = 5.30 \times 10^{-2} + 5.30 \times 10^{-1} \\ 0.01L & = 5.30 \times 10^{-2} + 5.30 \times 10^{-1} \\ 1.010^{-2} & = 5.30 \times 10^{-2} + 5.30 \times 10^{-1} \end{aligned} $$ $$ \begin{aligned} 7.00 \times 10^{-3} & = 7.00 \times 10^{-3} + 5.30 \times 10^{-2} \\ 10.00 \times 10^{-3} & = 5.30 \times 10^{-3} + 5.30 \times 10^{-1} \end{aligned} $$ **Step 5** What is the value of *K* for the reaction? (Use Eq. 2 and the results of Step 4.) $$ \begin{aligned} K_0 &= \frac{142}{142} \\ &\quad \text{(continued on following page)} \end{aligned} $$

2. Having obtained the volume of the flask above, the student emptied the flask, dried it, and filled it with an unknown liquid. The mass of the stoppered flask when completely filled with liquid was 50.376 g . a. What was the mass of the unknown liquid? $\qquad$ b. What was the density of the unknown liquid? $\qquad$ $\mathrm{g} / \mathrm{mL}$ 3. The student then emptied the flask and dried it once again. To the empty flask he added pieces of a metal until the flask was about half full. He weighed the stoppered flask containing the metal and found that its mass was 106.366 g . Next, he filled the flask containing the metal with water, stoppered it, reweighed it and obonised a total mass of 121.860 g . a. Find the mass of metal in the flask $\qquad$ # DENSITY MEASUREMENTS OF LIQUIDS AND SOLIDS ## ADVANCE STUDY ASSIGNMENT ## Name 1. A student obtained a clean, dry, glass-stoppered flask. He weighed the flask and stopper and found the total mass to be 22.624 g . He then filled the flask with water, weighed again, and obtained a mass of 59.479 g . At the temperature of the water, he found that its density was $0.9973 \mathrm{~g} / \mathrm{mL}$. a. What was the mass of the water? $\qquad$ g b. What was the volume of the water? $\qquad$ mL c. What was the volume of the flask? $\qquad$ mL

Is the baking of a cake a chemical change or a physical change? Justify your answer.

" Identify what reagents you would use to achieve each transformation: (a) Conversion of 2-methyl-2-butene into a secondary alkyl halide (b) Conversion of 2-methyl-2-butene into a tertiary alkyl halide (c) Conversion of cis-2-butene into a meso diol (d) Conversion of cis-2-butene into enantiomeric diols"

Choose the correct Lewis electron-dot diagram for an atom of boron. | 1. | $\cdot \mathrm{B}^{\cdot}$ | | --- | --- | | 2. | $\mathrm{B}^{\cdot}$ | | 3. | $: \mathrm{B}:$ | | 4. | $: \mathrm{B}^{\cdot}$ |

Brand of vinegar or unknown no. | | | Dish | | | --- | --- | --- | --- | | | Trial 1 | Trial 2 | Trial 1 | | 1. Mass of flask (g) | 40.3016g | 91.0265g | 73.8552g | | 2. Mass of flask + vinegar (g) | 45.8638g | 94.9985g | 78.5294g | | 3. Mass of vinegar (g) | 5.5522g | 3.912g | 4.6742g | | B. Analysis of Vinegar Sample | | | | | 1. Buret reading of NaOH, initial (mL) | 0 mL | 0.5 mL | 0 mL | | 2. Buret reading of NaOH, final (mL) | 28 mL | 28 mL | 28.5 mL | | 3. Volume of NaOH used (mL) | 28 mL | 27.5 mL | 28.5 mL | | 4. Molar concentration of NaOH (mol/L) | 0.11635 mol/L | | 0.11635 mol/L | | 5. Moles of NaOH added (mol) | 3.2578 x10-3 mol | 3.199625 x10-3 mol | 3.315975 x10-3 mol | | 6. Moles of CH₃COOH in vinegar (mol) | 3.2578 x10-3 mol | 3.199625 x10-3 mol | 3.315975 x10-3 mol | | 7. Mass of CH₃COOH in vinegar (g) | 0.195468g | 0.1919775g | 0.1989585g | | 8. Percent by mass of CH₃COOH in vinegar (%) | 3.52% | 5% | 4.3% | | 9. Average percent by mass of CH₃COOH in vinegar (%) | 4.27% | | | *Calculations for Trial 1 of the first vinegar sample on next page.

What is the chemical formula for the compound strontium sulfide, which contains $S r^{2+}$ and $S^{2-}$ ions?

Thiols have structures similar to alcohols except that they contain A) sulfur in place of oxygen in the functional group. B) lithium in place of oxygen in the functional group. C) more than one carbon. D) three alcohol groups. E) nitrogen in place of oxygen in the functional group. When a primary alcohol is completely oxidized, the product is A) a carboxylic acid. B) an aldehyde. C) another alcohol. D) an alkene. E) a ketone. 36 Mennanol is used in all the following except A) solvents. B) making plastics. C) paint remover. D) racing fuel. E) alcoholic beverages. Secondary alcohols are oxidized to A) esters. B) carboxylic acids. C) ketones. D) aldehydes. E) ethers.

"What is the difference between cations and anions? A. Anions become less dense as they cool, whereas cations increase in density as they cool. B. Cations have an absolute charge greater than one, and anions are neutrally charged. C. Cations have a positive charge, and anions have a negative charge. D. Anions are attracted to the magnetic north pole, and cations are attracted to the magnetic south pole."

What happens to electrons in ionic bonds?

"Give the name or formula of the following ionic compound: Vanadium (V) phosphate"