Organic Chemistry Questions

In a chemistry lab test, you are asked to react a solution of bromine with each of the following unknown liquids. Which one decolourizes the bromine solution? a. 2,3-dimethylbutane b. ethanoic acid c. cyclohexene d. n-methylmethanamide

Which of these is a significant ethical dilemma that a drug designer may face? A. A new drug effectively fights allergies but causes drowsiness. B. A new drug effectively treats skin cancer but may cause minor skin rashes during treatment. C. A new drug effectively lowers blood pressure but may cause headaches. D. A new drug treats hypothyroidism but destroys the thyroid; this means that patients will be on the drug indeterminately.

What is the difference between science and pseudoscience? A. Science is based on observation, while pseudoscience is based on experimentation. B. Pseudoscience is based on observation, while science is based on experimentation. C. Pseudoscientific conclusions are based on empirical evidence, while scientific conclusions are not. D. Scientific conclusions are based on empirical evidence, while pseudoscientific conclusions are not.

What does Le Châtelier's principle state? A. A reaction at equilibrium will go to completion when the equilibrium is upset. B. A reaction will form a new equilibrium ratio when the equilibrium is upset. C. A reaction at equilibrium will respond to balance a change. D. A reaction at equilibrium will not respond to a change.

You work at a factory that produces ammonia gas. The reaction gives off heat. If the reaction is at equilibrium, how can you force the reaction to produce more products? Please choose the correct answer. Increase the temperature. Decrease the temperature. Changing the temperature has no effect.

You would like to make 3.1 L of a NaCl solution that has a concentration of 2.8 M. How many grams of salt (NaCl) will you need to make your solution?

Which of the statements below are true? A. Round bottom flasks always have 14/20 glass joints B. Round bottom flasks usually are equipped with male joints C. When greasing glassware, you should always grease the joint of the round bottom flask D. Round bottom flasks are only used to heat the reaction mixtures E. Round bottom flasks are usually equipped with female joints F. Round bottom flasks should be filled just to 1/3 of the volume.

A double-blind study is one in which neither the researchers nor the subjects know whether the subject is receiving the real treatment or the placebo. What is the value of this kind of study? A. The researchers cannot replace the placebo with the real treatment for their favorite subjects. B. Neither the subjects nor the researchers can bias the results. C. The subjects are not irritated by the fact that they are not receiving the real treatment. D. Neither the subjects nor the researchers are able to interpret the results.

Barium can be analyzed by precipitating it as BaSO4 and determining the mass of the precipitate. When a 0.269-g sample of a barium compound was treated with excess H₂SO4, 0.0891 g of BaSO4 formed. What percentage of barium is in the compound?

4 The black "tarnish" that can develop on silver objects is a result of the metal reacting with sulfur-containing compounds in the air to produce silver sulfide. A sample of silver sulfide was found to contain 90.64 g of silver and 13.47 g of sulfur. Use these data to calculate the empirical formula of silver sulfide.

The process of using computers and robots to conduct thousands of tests to determine the interaction between different compounds and a disease is called what? A. Evaluating test results B. High-throughput screening C. An intravenous solution D. The engineering process

A scientist has just developed a composite drug to fight seasonal allergies. What's the next step in the engineering process before the drug is released? A. Analyzing the strengths and weaknesses of each drug currently on the market B. Determining if any other diseases might also benefit from this composite drug C. Researching how each drug has been used in the past D. Testing the composite drug in a trial run.

(Ba(C₂H₂O₂)₂) working solution. She'll do this by pouring out some 0.484 M A chemist must prepare 250. mL of 475. mM aqueous barium acetate aqueous barium acetate stock solution into a graduated cylinder and diluting it with distilled water. Calculate the volume in mL of the barium acetate stock solution that the chemist should pour out. Be sure your answer has the correct number of significant digits.

Why are no unauthorized experiments permitted in the lab? A. The student lacks experience in the lab B. Most professors love to sée only their selected experiments performed C. The stockroom may not have the reagents that you need D. It may take more time to perform than expected

You determine the empirical formula of a compound to be CH3. In a separate experiment, you determine the molar mass of the compound to be 90.208 g/mol. What is the molecular formula for this compound? (When entering your answer, you do not need to use subscripts - for example, you could write C1202 for the empirical formula Cl₂0₂.)

Some vitamins and dietary supplements are stored in opaque, darkened bottles to protect them from UV light because UV light would cause a reaction. Which word could be used to describe UV light in this situation? A. Reactant B. Catalyst C. Solvent D. Enzyme

A solution of ammonia NH3(aq) is at equilibrium. How would the equilibrium change if OH- were added to the solution? A. [NH4+] and [OH-] would increase. B. [NH4+] and [OH-] would decrease. C. [NH4+] and [H*] would decrease. D. [NH4+] would increase and [OH-] would decrease.

You analyzed 2.475 g of a mixture of NaCl, SiO₂, and CaCO. You isolate 0.825 g NaCl, 0.825 g of CaCO3, and 0.580 g SiO₂. You were told that the original mixture contained 35% NaCl, 45% CaCO3, and 20% SiO₂. Report two possible sources of error.

A chemist prepares a solution of magnesium bromide (MgBr₂) by measuring out 0.90 g of MgBr₂ into a 100 mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of Br anions in the chemist's solution. Be sure your answer is rounded to the correct number of significant digits.

You ask a classmate to measure the mass of a large beaker, and they record a mass of 22.5 ounces. However, you wish to know the mass in kilograms. Convert this mass to kilograms (kg) and report below to the correct number of significant figures. You can show your work here or on a separate sheet of paper to receive partial credit for your answer.

You time travel 100 years into the future and learn that several new elements have been discovered, as pictured. These elements are frequently found as oxides, and need to be separated in order to extract the pure element. Before going through this effort, it is useful to know what amount of the element can be extracted. What is the mass percent composition of element A in the compound A505?

A chemist must dilute 98.4 mL of 49.3 mM aqueous sodium carbonate (Na₂CO3) solution until the concentration falls to 14.0 mM. He'll do this by adding distilled water to the solution until it reaches a certain final volume. Calculate this final volume, in liters. Be sure your answer has the correct number of significant digits.

A chemist dissolves 197. mg of pure nitric acid in enough water to make up 260. mL of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.

A chemist makes 790. mL of zinc nitrate (Zn(NO3)₂) working solution by adding distilled water to 70.0 mL of a 0.521 M stock solution of zinc nitrate in water. Calculate the concentration of the chemist's working solution. Be sure your answer has the correct number of significant digits.

Acetylene (C₂H₂) gas is often used in welding torches because of the very high heat produced when it reacts with oxygen (O₂) gas, producing carbon dioxide gas and water vapor. Calculate the moles of acetylene needed to produce 0.075 mol of carbon dioxide. Be sure your answer has a unit symbol necessary, and round it to the correct number of significant digits.

A chemist adds 410.0 mL of a 3.7 x 10-5 mol/L mercury(II) iodide (Hgl₂) solution to a reaction flask. Calculate the micromoles of mercury chemist has added to the flask. Be sure your answer has the correct number of significant digits.

Each row of the table below describes an aqueous solution at about 25 °C. Complete the table. That is, fill in any missing entries in the second and third columns. Be sure each entry you write includes the correct number of significant digits.

Dr. A needs to make 125.0 mL of a 0.225 M solution of BaCl2. What mass (in grams) of barium chloride is needed to prepare this solution? Report your answer to the correct number of significant figures. You may show your work here or on a separate sheet of paper to receive partial credit.

Describe the procedure for smelling a chemical. A. Stick your nose close to the vessel and breath deeply B. Point vessel away from face while gently fanning vapors toward nose C. Never smell a chemical D. Smell chemical as you would anything else

Calculate the volume in milliliters of a 0.679M barium chloride solution that contains 75.0 mmol of barium chloride (BaCl₂). Be sure your answer has the correct number of significant digits.

Each sketch below shows three objects with an electric charge. In each case, decide whether there is a net force acting on the object outlined in green. If there is a net force, decide whether it pushes the green-ring object to the left or right. Then select the appropriate button under the sketch. For example, if there is a net force pushing the green-ring object in the first sketch to the left, select the left button under the first sketch. If there is no net force on the green-ring object in the second sketch, select the middle button under the second sketch. And so on.

Calculate the molality of a solution that contains 78.2 grams of Solute in 278.8 mL of solution. The following information may be useful for this calculation. The molar mass of Solute = 120.71 g/mol The density of the solution = 1.0 g/mL

Draw the skeletal ("line") structure of pentane.

A chemist prepares a solution of vanadium(III) chloride (VC13) by measuring out 0.12 g of VCI3 into a 300. mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of C1 anions in the chemist's solution. Be sure your answer is rounded to the correct number of significant digits.

Volatile solvents can cause irritation of the respiratory tract, intoxication, central nervous system depression, drowsiness, or nausea. How can you prevent accidental vapor inhalation? 1. work with volatile solvent in your student hood 2. cover containers of them if you have to carry them through the lab 3. both

A chemist dissolves 230. mg of pure hydrochloric acid in enough water to make up 350. mL of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.

A chemist must dilute 55.5 mL of 23.0 µM aqueous magnesium fluoride (MgF₂) solution until the concentration falls to 17.0 μM. He'll do this by adding distilled water to the solution until it reaches a certain final volume. Calculate this final volume, in milliliters. Be sure your answer has the correct number of significant digits.

Draw the condensed structure of a primary amine with 3 carbon atoms, and no double or triple bonds.

Gasecus ammonia chemically reacts with oxygen (0.) gas to produce nitrogen monoxide gas and water vapor. Calculate the moles of nitrogen monoxide produced by the reaction of 2.10 mol of oxygen. Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.

Calculate the volume in milliliters of a 0.527M aluminum sulfate solution that contains 425. mmol of aluminum sulfate (Al₂(SO4)3).

Write the systematic name of each organic molecule: structure CH3 CH2CH₂CH2CH₂CH₂- -CH2CH2CH₂CH₂CH₂CH3 CH3CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH3 CH3CH2CH3

A chemist dissolves 374. mg of pure hydroiodic acid in enough water to make up 250. mL of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.

Draw the Lewis structure for ethylamine (C2H7N). Ethylamine molecules have one amino group. Be certain you include any lone pairs.

A chemist dissolves 191. mg of pure perchloric acid in enough water to make up 80. mL of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.

Wine goes bad soon after opening because the ethanol (CH₂CH₂OH) dissolved in it reacts with oxygen (O₂) gas to form water and aqueous acetic acid (CH3COOH), the main ingredient in vinegar. Calculate the moles of acetic acid produced by the reaction of 0.10 mol of ethanol. Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.

An aqueous solution at 25 °C has a H₂O+ concentration of 6. × 10 M. Calculate the OH concentration. Be sure your answer has the correct number of significant digits.

A chemist prepares a solution of iron (II) bromide (FeBr₂) by measuring out 3.00 g of FeBr₂ into a 300. mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of Br anions in the chemist's solution. Be sure your answer is rounded to the correct number of significant digits.

A chemist prepares a solution of vanadium(III) bromide (VBr3) by measuring out 3.00 g of VBr3 into a 300. mL volumetric flask and filling to the mark with distilled water. Calculate the molarity of Br anions in the chemist's solution. Be sure your answer is rounded to the correct number of significant digits.

Suppose a student starts with 2.3816 g of a sand mixture and separates the components, recovering 1.3012 g of NaC1, 0.5809 g of SiO2, and 0.4503 g of CaCO3. What is the percent recovery of the mixture?

An aqueous solution at 25 °C has a OH concentration of 2.7 x 10 M. Calculate the H₂O concentration. Be sure your answer has the correct number of significant digits.