General Questions and Answers

4 Al (s) + 3 02 (g) Answer: - 2 Al2O3 (s) How many grams of Al (s) are needed to produce 197.8 g of Al2O3 if the percent yield for this reaction is 83.2% ? Assume that oxygen is present in excess. Do NOT include units in your answer. If you round during your calculation, be sure to keep at least three (3) decimal places. Report your answer to one (1) decimal places.

Drag each item to the correct box. Rank the following atoms in order of increasing electronegativity. least electronegative N most electronegative

Identify which sets of chemical reactions resulted in a white precipitate. (HINT: Please refer to the completed chart that you filled out during the hands-on lab OR the virtual video lab. You will need to look for the chemical sets that provided the color of precipitate listed above.) Select 3 correct answer(s) BaCl2 + AgNO3 Al2(SO4)3 + Ba(NO3)2 BaCl2 + KCI Na2CrO4 + AgNO3 BaCl2 + K₂CRO4 BaCl2 + MgSO4

When the Roman Empire could no longer expand, what did it do to increase revenue for the government? A. It acquired more slaves from other parts of the world. B. It sells the land back to the barbarians. C. It taxes the citizens. D. It forced those that were not citizens to leave the empire.

How many grams of Al are need to react with 3.4 mol HCl? Given that 2 Al + 6 HCl → 2 AlCl3 + 3H₂ 0 25g O 15 g O 93 g O 1.1 g O 31 g O 275 g O 26 g

What is the wavelength of the matter wave associated with a proton moving at 315 m/s? wavelength of proton matter wave: wavelength of astronaut matter wave: What is the wavelength of the matter wave associated with a 155 kg astronaut (including her spacesuit) moving at the same speed? 125 x10 0-11 wavelength of Earth matter wave: x10 What is the wavelength of the matter wave associated with Earth moving along its orbit around the Sun? x10 m m m

Avobenzone is an active ingredient in some common sunscreens. Which of the following is the correct molecular formula for avobenzone? solla avobenzone Multiple Choice C20H2403 C20H2203 C2202203 C21H2303 < Prex 9 of 20 www www Next > 55°F Mos

The balanced reaction equation for combustion of heptane, C₂H16, i is C₂H₁6 + 110₂7CO₂ + 8H₂0 If the reaction produced 28.5 g CO₂, how many grams of heptane were burned? mass: The reaction of limestone with hydrochloric acid is CaCO3 + 2HCl → CaCl₂ + CO₂ + H₂O If the reaction produced 28.5 g CO2, how many grams of HCl reacted? mass: g C₂H16 g HCI

14. Which of the following "rules" is being violated in each electron configuration below? Explain your answer for each. Hund's Rule, Pauli Exclusion Principle, Aufbau Principle 11 12 13 ↑↓ ↑↓ 14. 1s 2s 2p ↑↓ 11 11 14 1s 2s 2p ↑↓ ↑↓ ↑↓↑↑↓ 2p 14 1s 2s - 3s TL TL ↑↓↑↑↓ ↑↑ ttttt 1s 2s 2p 3s 3p NIL 3p ↑↓ ↓ ↓ ↓ ↓↓↓↓↓ 3s 3p 3d

Consider compounds which contain both a heteroatom and a double bond. For which compound is no additional Lewis structure possible? Multiple Choice O || ||| IV 11 E ||| IV

A mixture of 8 moles of hydrogen and 6 moles of oxygen are used in the reaction. Use the coefficients from the balanced chemical equation in your calculation. a) How many moles of water would be produced if you used up all the hydrogen? [Select] mol b) How many moles of water would be produced if you used up all the oxygen? [Select] mol c) Given your answers above and assessing the limiting reactant, how many moles of water can be produced? [Select] mol d) Which is the limiting reactant? [Select] e) How many moles of excess reactant is left over?______moles start - moles used = moles left over [Select] mol excess reactant initially - [Select] mol excess reactant used = [Select] mol excess reactant left over

A. copper sulfate (CuSO4) solution and steel wool (Fe). (6 pt.) balanced equation total ionic equation net ionic equation reaction type B. steel wool (Fe) and sulfur (S8) (4 pt.) balanced equation reaction type

The unbalanced equation above shows carbon and silicon dioxide reacting to form silicon carbide (SiC, molar mass = 40.1 g/mol) and copper. Balance it before beginning. Silicon carbide is a semiconductor, and copper is an excellent conductor of electric current. Previously cited A large electronics company is creating and testing SiC for use in new computer chips. A chemical technician has 22.0 g of each reactant. Assuming a 100% yield, what mass (in grams) of silicon carbide can be created from what the technician has available? g Sic Answer:

Balance the following equation: NH4NO3 (s) →→→ N₂ (g) + _O₂ (g) +______H₂O (1) • What is the coefficient for water in the balanced chemical equation? . If you begin with 55.2 g NH4NO3, what is the theoretical yield of water? g H₂0 • If the percent yield is 82.6 %, what mass of liquid product was actually obtained in the reaction? g H₂ Use the included Periodic Table for all molar mass values. Give 3 significant figures in all answers.

(1pts) is this chemical equation balanced? P+80₂4PO, (1pts) (1pts) 13. If you have 0.38 moles of P how many moles of O₂ would be needed to react? 14. If you have 0.28 moles of Os how many moles of PO₂ can be produced? 15. If you produce 8.07 moles of PO₂, how many moles of P, are required? (9pts) Stoichiometry (Chemical Calculations) Choose... Saved

Boyle's law. Let's return our balloon to the room again, where it's 26°C. Now imagine that you take an empty 0.500 L plastic pickle jar and gently push the balloon inside the jar: Now screw on the lid. What will happen to the pressure inside the balloon when you close the lid? (2 pts/ 0.4pt each) (a) Circle the correct words in the parentheses to complete the following sentence. The pressure in the balloon will (increase/decrease) (slightly/dramatically). In this experiment (volume/temperature/amount of gas) (is/are) constant. (b) Write an equation using the information from (a) that compares the initial state of the balloon and to its final state. P1V1= P2V2 (c) Calculate the new pressure (in torr) using the ideal gas law or the equation written from your answer in (b). P=?atm V1=0.500 L (d) Now explain the change in pressure based on the behavior of the gas molecules.

Refer to Q#4: Draw the Lewis structure for the FCN molecule. As modeled and discussed in the live session: How many electrons are present in the Lewis Dot Structure for FCN? O 16 18 O 20 O 14

A student intended to make a salt solution with a concentration of 10.0 grams of solute per liter of solution. When the student's solution was analyzed, it was found to contain 8.90 grams of solute per liter of solution. What was the percent error in the concentration of the solution? 1) 1.10% 2) 8.90% Experimental value: Theoretical value: Percent error = 3) 11.0% 4) 18.9%

When you calculate the density of chemical A experimentally you get 1.13 g/mL. The actual density according to the literature is 1.16 g.mL. What is your percent error? Experimental value: Theoretical value: Percent error =

2Mg(s) + O₂(g) →→→ 2MgO(s) A college chemistry student is performing this reaction in a lab, where magnesium is burned and combines with oxygen from the air to produce magnesium oxide. The students burns 2.92 g of Mg, and there is excess oxygen from the air. They incorrectly calculated that the mass of magnesium oxide produced was 2.42 g. Here is their work: 2.92 g 1 mol 2 mol X X 24.3 g 1 mol X 40.3 g = 2.42 g - 1 mol 1) What did the student do wrong? There is an error in their work. Explain specifically what part is incorrect. (2 pts) 2) What recommendation(s) would you give to the student regarding showing their work? There is an improvement that can be made to help them avoid this mistake in the future. (2 pts) 3) Instead of 2.42 g, what answer should the student have gotten? (2 pts)

Phosphorus trichloride is produced by the reaction of phosphorus and chlorine as shown in the following balanced chemical equation. P4 (s) + 6 Cl₂ (g) → 4 PC13 (1) Consider the reaction of 125 g P4 and 322 g Cl₂. 1. Determine the maximum amount of PC13 that can be formed from the mass of P4 (in grams). g PC13 to 3 SF 2. Determine the maximum amount of PC13 that can be formed from the mass of Cl₂ (in grams). g PC13 to 3 SF 3. Based on your answers above, what mass of PC13 is expected to form? g PCI; to 3 SF 4. What is the limiting reactant? blank) 5. How much excess reactant (in grams) is left at the end of the reaction? • Start - used=left over (put numbers in blanks in this order) g to start with - O (write phosphorus or chlorine in the g used in the reaction = g left over at the end of the reaction. 6. If the percent yield is 84.5 %, what mass of PC13 was obtained in the reaction (actual yield)? g PC13 to 3 SF

How many grams of Al2O3 can form from 38.8 g of Al? 4 Al(s) + 3 O₂(g) → 2 Al₂O3(s) Step 1: Show the strategy for solving this problem. grams Al -> grams Al₂O3

For the following reaction, 14.9 grams of sulfur are allowed to react with 17.3 grams of carbon monoxide. sulfur (s) + carbon monoxide (g)-sulfur dioxide (g) + carbon (s) What is the maximum amount of sulfur dioxide that can be formed? What is the FORMULA for the limiting reagent? What amount of the excess reagent remains after the reaction is complete? grams grams

How many grams of Cl₂ are needed to form 79.7 g of AICI, ? 2 Al(s) + 3 Cl₂(g) ->> 2 AICI, (s) Step 1: Show the strategy for solving this problem. grams AlCl3 - grams Cl₂

A molecular compound has the following empirical formula: CH₂O. The molar mass of the empirical formula is g. Write your answer using 3 significant figures. If the molar mass of the molecular compound is 180.0 g/mol, write the molecular formula of the compound.

Based on periodic trends, which element below has the greatest electronegativity? O Potassium (K) O Fluorine (F) O Bromine (Br)

Write the molecular and net ionic equations, including phases, for the reaction that occurs between aqueous sodium chloride, NaCl, and aqueous silver nitrate, AgNO3. molecular equation: net ionic equation:

PC15 (s) + H₂O(1) POCl3 (1) + 2HCl(aq) When 58.15 g of phosphorus pentachloride reacts with excess water, what mass of hydrogen chloride will be produced? If needed, enter scientific notation with the "e". For example, 1.44x107 would be entered as 1.44e7. Answer: g HCI.

The hydrides of group 5A are NH3, PH3, AsH3, and SbH3. Arrange them from highest to lowest boiling point. Rank the molecules from highest to lowest boiling point. To rank items as equivalent, overlap them. View Available Hint(s) PH3 NH3 SbH3 AsH3

Indicate the major type of intermolecular forces between particles in each of the following compounds. Drag the appropriate items to their respective bins. Dipole-dipole attractions NH3 HBr OBr2 CHCl3 Dispersion forces CF4 Hydrogen bonds lonic bonds LICI Reset Help

Select the correct answer. Which reaction is a decomposition reaction? OA. 2KCIO3- 2KCI +30₂ 4Na + O₂ → 2Na₂O ZnS +30₂ ZnS + 30₂ → 2ZnO + 250₂ 2NaBr + CaF₂ → 2NaF + CaBr₂ B. O C. O D.

You are given the number of grams of compound NO₂ and are asked to determine the number of mol in the sample Choose the respond that best describes what is needed to solve this problem. a. the g of NO₂ sample is divided by the molar mass of NO2 in g/mol Ob. the molar mass of NO₂ in g/mol is divided by the grams NO₂ in the sample O c. the mol of NO₂ is multiplied by the molar mass of NO₂ in g/mol 2 points

Calculate the number of pounds of CO₂ released into the atmosphere when a 17.0 gallon tank of gasoline is burned in an automobile engine. Assume that gasoline is primarily octane, Cg H₁g, and that the density of gasoline is 0.692 g mL-¹. This assumption ignores additives. Also, assume complete combustion.

With respect to membrane transport, diffusion driven transport requires no external energy active transport always moves at least one molecule with a concentration gradient O ATP is the only source of energy for active transport O all of the above are true O none of the above are true

Indicate whether or not a precipitate forms when aqueous solutions of the following soluble compounds are mixed. If a precipitate forms, write the net ionic equation for the reaction. A precipitate is formed for products that are insoluble and slightly soluble. a) Na₂S and Sr(NO3)2 b) NH4NO3 and NaBr c) KCl and NaCl d) K₂SO4 and Bal₂

How many molecules of NH Br are in 3.746 g of NH Br? Show the conversions required to solve this problem and calculate the molecules of NH Br. 3.746 g NH Br x amount of NH Br = 1 mol NH Br Answer Bank 6.022 x 1023 molecules NH Br = ? molecules NH Br 1 mol NH₂ Br 97.94 g NH₂ Br molecules NH Br

This activity will help you begin balancing simple chemical equations. Five of the spaces below will have NO number on them. This means that those spaces each hold an invisible ONE. Remember, in a balanced chemical equation, there are equal numbers of each atom on each side of the arrow. Good luck! 1) Zn+0₂ → _ZnO 2) ____ HI → - 3)____B +_ F₂ → ___ BF3 - 5)__ Fe + H₂ + 1₂ 4)__N+ _H,> _NH, _H₂ → — H₂O → Fe3O4 + - —— H₂

3. Which of the following describes the relationship between Jim Crow and Plessy v. Ferguson? O A Jim Crow segregation laws compelled Plessy to protest segregated trains. OB Jim Crow segregation laws were made possible by the Plessy v. Ferguson decision. OC OD Plessy v. Ferguson made Jim Crow laws widely accepted, but not officially legal. Plessy v. Ferguson hoped to end the segregation common during Jim Crow.

Where is the lanthanide series located? far left side of the periodic table far right side of the periodic table O in the middle of the periodic table underneath the main section of the periodic table

Calculate the mass of precipitate formed when aqueous solutions of the following reactants are mixed, assuming that the reaction goes to completion. a) 50.0 mL of 0.150 M (NH4)2SO4 and 100. mL of 0.100 M CaBr₂ 10.0 mL of 0.525 M NaCl and 20.0 mL of 0.250 M Pb(NO3)2 c) 15.0 mL of 0.235 M Na₂SO3 and 10.0 mL of 0.525 M BaCl₂ b)

How many grams of AlPO4 are in 5.56 x 1021 molecules of AIPO? Show the conversions required to solve this problem and calculate the grams of AlPO4. 5.56 x 1021 molecules AlPO4 X mass AlPO4 = 1 mol AlPO4 1 mol AlPO4 Answer Bank 6.022 x 1023 molecules AIPO4 = ? g AlPO4 121.95 g AIPO4 g AIPO 4

Consider the reaction. CaCl₂(aq) + K₂CO3(aq) → CaCO3 + 2 KCI Identify the precipitate, or lack thereof, for the reaction. O no precipitate OKCI O CaCO3 Consider the reaction. FeCl,(aq) + (NH4),SO4 (aq) — FeSO4 +2NHẠCI Identify the precipitate, or lack thereof, for the reaction. O NH CI no precipitate O FeSO4

Suppose you heat a metal object with a mass of 32.9 g to 96.6 °C and transfer it to a calorimeter containing 100.0 g of water at 17.2 °C. The water and metal reach a final temperature of 22.4 °C. What is the specific heat of the metal inc? Type answer:

Watch the animation and select the interactions that can be explained by hydrogen bonding. Check all that apply. View Available Hint(s) OCH4 molecules interact more closely in the liquid than in the gas phase. Ice, H₂O, has a solid structure with alternating H-O interactions. OH₂ Te has a higher boiling point than H₂S. OHF is a weak acid neutralized by NaOH. HF has a higher boiling point than HCl.

A chemist dissolves 491. mg of pure barium hydroxide in enough water to make up 170. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Round your answer to 3 significant decimal places.

At the start of nerve transmission, O potassium gates open to attempt to restore the charge imbalance caused by opening of the sodium gates the first ions to move are protons the second ion to move is sodium all of the above are true 4 pts none of the above are true

in Appendix 1 of this lab write the balanced molecular equation for each of the precipitation reactions in aqueous solution and the net ionic equation for the precipitate that is formed. Indicate the phase, (aq), (1), (s), or (g), for each of the reactants and products. The formation of a precipitate is indicated as a solid, (s). A precipitate is formed for products that are insoluble and slightly soluble. a) Ammonium chloride reacts with silver nitrate. b) Sodium carbonate reacts with calcium bromide. c) Barium nitrate reacts with magnesium sulfate. d) Sodium phosphate (Na3PO4) reacts with lead nitrate (Pb(NO3)2).

Balance the equations by inserting coefficients as needed. equation 1: CaCO3 + HCl equation 2: CaCl₂ + CO₂ + H₂O CaH₂ + H₂O → Ca(OH)₂ + H₂

Identify which of the following molecules can exhibit hydrogen bonding as a pure liquid. Check all that apply. ► View Available Hint(s) F OF-C-F I F O H-C-H H H OF-C-H F H N H OH-0-0-H H₂C-H₂C-0-H OH-Cl

For an experiment a scientist needs a 0.445 L solution of 0.725 M acetic acid. The labs has a bottle of 18.3 M concentrated acetic acid. What volume in milliliter (mL) of the concentrated acetic acid does the scientist need to use to create their solution? O 17.6 mL O 0.0176 mL O 11.2 mL O 11200 mL O 29.8 mL