Chemistry Questions and Answers

20. Sodium azide, $\mathrm{NaN}_{3}$ is best known as the chemical found in automobile airbags. When the car undergoes a head-on collision, chemical reactions occur inside the gas generator will generate nitrogen gas $\left(\mathrm{N}_{2}\right)$ by the rapid decomposition of $\mathrm{NaN}_{3}$ to fill the airbag. $$ 2 \mathrm{NaN}_{3}(\mathrm{~s}) \rightarrow 2 \mathrm{Na}(\mathrm{~s})+3 \mathrm{~N}_{2}(\mathrm{~g}) $$ For the air bag to operate correctly, calculate the amount (mass) of $\mathrm{NaN}_{3}$ needed in the gas generator to generate $\mathrm{N}_{2}$ gas that is completely fill 65 L of nylon airbag to a pressure of 980 mmHg at $25.0^{\circ} \mathrm{C}$.

I. Arrange the following steps chronologically. Use 1 as the first step, 2 for the second step and so on. Write the number before the letter. A. Add 4 gtts of K2CrO4 into the centrifugate. B. Place 10 drops of the solution to be analyzed in a test tube. C. Dissolve the precipitate in 2 drops of concentrated nitric acid. D. Add 6-7 drops of water and heat. E. Discard the wash water F. Keep the mixture hot in a steam bath G. Test for the completeness of precipitation H. Add 1-2 drops of SnCl 2 I. Instill 10 drops of 3F Ammonia J. Yellow precipitate confirms the presence of Lead ion. K. Wash the precipitate with 10 drops of cold water L. White or gray precipitate confirms the presence of mercurous ions.

Which of the following is the correct Lewis structure for carbon dioxide (CO₂)? A. Central C singly bound to two O atoms, no non-bonding electrons B. Central C singly bound to two O atoms, double-bonded O with 2 electron pairs C. C double-bonded to 2 O atoms, each O has 2 lone pairs of electrons D. One C atom in the center, single-bonded to two O atoms, no other bonds, each O has three lone pairs of electrons

"Which statement best describes the trend in atomic radii observed in the periodic table? The atomic radii increase, moving across a period to the right and up in a group. The atomic radii increase, moving across a period to the left and down in a group. The atomic radii increase, moving across a period to the left and up in a group. The atomic radii increase, moving across a period to the right and down in a group."

"What is the charge on the barium ion? (The symbol for barium is Ba) "

"Which statement best describes the electronegativity of an element? A. Electronegativity of an atom is its ability to lose electrons during cation formation. B. Electronegativity of an atom is its ability to share electrons during a covalent bond formation. C. Electronegativity of an atom is its ability to gain electrons during anion formation. D. Electronegativity of an atom is its ability to produce energy while losing an electron. E. Electronegativity of an atom is its ability to attract electrons during bond formation."

Calculate the number of nitrogen atoms in a 110.0 g sample of hydrazine (N₂H₄). Be sure your answer has a unit symbol if necessary, and round it to 4 significant digits.

| 4 | Name the following compound: $\mathrm{N}_{2} \mathrm{O}_{5}$. <br> nitrogen oxide <br> Dinitrogenpentoxide <br> Dinitrogen hexoxide <br> Dinitrogen octaoxide <br> Dinitrogen fiveoxide | | :--: | :--: |

"Determine the molecular geometry for SF₄. A. Square pyramidal B. Trigonal bipyramidal C. Seesaw D. Square planar E. T-shape"

What is the charge on an ion of sodium (Na)?

"An atom of an element contains 6 protons, 6 neutrons, and 6 electrons. An atom that is a different isotope of this element would contain — A. 6 protons, 7 neutrons, and 6 electrons. B. 6 protons, 6 neutrons, and 7 electrons. C. 7 protons, 6 neutrons, and 6 electrons. D. 7 protons, 7 neutrons, and 7 electrons."

| atom | subshell from which electron removed to form +1 cation | subshell to which electron added to form -1 anion | | --- | --- | --- | | H | 1s | 1s | | Ne | 2p | 3s | | Cl | 11 | 1 | | Sc | 4s | 3d |

What is the electronic geometry and the molecular geometry of BF3?

Draw the Lewis structure for the polyatomic phosphite $\left(\mathrm{PO}_{3}^{3-}\right)$ anion. Be sure to include all resonance structures that satisfy the octet rule. | | | | | | --- | --- | --- | --- | | $\mathrm{O}^{2-}$ | $\mathrm{P}-\mathrm{O}$ | | | | | 0 | | | | | | | | | --- | --- | --- | --- | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

What is the name for CH3CO2-

"What is the molecular geometry of carbon dioxide, CO₂? A. bent B. linear C. tetrahedral D. trigonal pyramidal E. not enough information"

"Which equation is balanced? A. 2Al + 3F2 → 2AlF3 ​ B. Al + 3O2 → Al2O3 C. Na + F2 → 2NaF D. Mg + 2O2 → 2MgO"

Provide the formula for each compound. hydrochloric acid: strontium carbonate: dinitrogen trioxide:

What is the molecular geometry of C2H4?

"Draw the Lewis structure of HCN. Include lone pairs."" is a complete question. It clearly asks for: The Lewis structure of hydrogen cyanide (HCN). That lone pairs should be shown."

How many valence electrons does a nitrogen atom possess?

Although silver can form +1 and +2 cations, the +2 is so rare that we usually name Ag+ silver ion, not silver(I) ion. Ag2+ is named silver(II) ion.

| compound | name | | --- | --- | | CH_{3} CH_{2} CH_{3} | ☐ | | CH_{3} — CH — CH_{3} | ☐ | | CH_{3} CH_{3} CH_{2} — CH_{2} — CH_{2} — CH_{3} CH_{2} — CH_{3} | ☐ | | CH_{3} CH_{2} CH_{3} — CH — CH_{2} — CH_{2} — CH_{3} | ☐ |

"For each ionic compound formula, identify the main group to which X belongs: (c) X(NO3)2 ​"

Question Almond Joy: Draw the skeletal structure of the product formed form this last combination (see screenshot below) Note: the question is referring to the last free radical combination you can possibly make in the given scenario. The presentation already demonstrated the Cl to Cl free radical combination, and the combination of the alkane free radical and the Cl free radical. What is the last possible combination of free radicals you can make given you have the choices of Cl and alkane free radicals (hint: the free radical can combine with another free radical of its type like the Cl to Cl)?

"Predict the molecular geometry for C2H4. A. Linear B. Bent C. Tetrahedral D. Trigonal Planar "

"Choose the two-letter symbol from the periodic table. A. Fe B. Mg C. Zn D. Sn"

4. Provide the major organic product of the following reaction.

Draw a Lewis structure for NO, indicating whether NO could be expected to be a stable molecule from the Lewis structure. Draw a molecular orbital diagram for NO. Does MO theory predict NO to be stable (include bond order in your answer)? Comment on the differences between predictions from the Lewis structure and that from MO theory.

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 | | --- | --- | | N, Be, F | | | $\mathrm{B}^{2+}, \mathrm{B}, \mathrm{Be}$ | | | I, F, Cl | |

2. A solution of KCl is saturated at 50°C. Use Table 9.1 (a) How many grams of solute are dissolved in 100 g of water? (b) What is the total mass of the solution? (c) What is the mass percent of this solution at 50°C? (d) If the solution is heated to 100°C, how much more KCl can be dissolved in the solution without adding more water? (e) If the solution is saturated at 100°C and then cooled to 30°C, how many grams of solute will precipitate out?

draw the lewis structure for chlorate (ClO3^-). for this structure, give each atom an octet and do not include a formal charge

What is the molar mass of butane, C4H10 ? I got 58.12 g/mol Calculate the mass of water produced when 8.80 g of butane reacts with excess oxygen. Calculate the mass of butane needed to produce 76.2 g of carbon dioxide.

Question 3: Draw the molecule given the following spectrums and molecular formula.

# Data Table 2: Sodium Hypochlorite SDS information | Items | SDS information | | --- | --- | | Physical State | close light green liquid | | Route of Exposure & Symptoms | cache shortness of breaths | | Protective Equipment | safe sheets for eye protection | | First Aid Procedures | exposed individual to teeth air | | Fire-fighting Measures | unsuitable extinguishing (agent) | | Chemical Reactivity | non-reactive under normal condition | | Safe Storage | 2 store away from oxidian agent | | Safe Disposal | reach sewage system or paper water | | Environmental/ Ecotoxicity | water stays very toxic to aquatic animals | | Spill Cleanup Procedures | |

What is the IUPAC name for the compound shown? # 2011 ## 2011

Complete the table below by listing the properties of ionic and covalent compounds. | Property | Ionic | Covalent | | Boiling Point | | | | Melting Point | | | | Solubility | | | | Conductivity | | |

(+)-Tartaric acid has a specific rotation of +12.0°. What is the specific rotation of a mixture of 75% (+)-tartaric acid and 25% (-)-tartaric acid? A. +4.0° B. +6.0° C. +8.0° D. +9.0°

# **SEWALS** Structures and Molecular Models For each of the following molecules or processes may be an instance of through it using the molecules created in the chemical system. These interactions are based on chemical energy values. 1. Calculate the total number of certain molecules in each reaction. 2. Determine the number of the molecules in the same reaction as the one in which the reaction occurs. 3. Determine the number of molecules that are in the same reaction. The number of molecules that are in the same reaction is defined as the number of the molecules in which the reaction occurs. The number of molecules that are in the same reaction is defined as the number of the molecules in which the reaction occurs. The number of molecules that are in the same reaction is defined as the number of the molecules in which the reaction occurs. 4. Determine the number of molecules that are in the same reaction. The number of molecules that are in the same reaction is defined as the number of the molecules in which the reaction occurs. The number of molecules that are in the same reaction is defined as the number of the molecules in which the reaction occurs. | Molecular model | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Molecular model | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 2 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 3 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 4 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 5 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 6 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 7 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 8 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 9 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 10 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 11 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 12 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 13 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 14 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 15 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 16 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 17 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 18 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 19 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 20 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 21 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 22 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 23 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 24 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 25 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

Which of the following statements best describes a limiting reactant? A. It is the reactant that determines the amount of product formed. B. It is the reactant that remains when the reaction is complete. C. It is the reactant that has the smallest mass. D. It is the reactant that reacts the fastest.