Qualitative analysis Questions and Answers

Octane reacts with oxygen gas producing carbon dioxide and water. Write the reaction equation, balance, and calculate the number of moles of octane consumed during the reaction if 0.172 moles of carbon dioxide are produced.

166 grams of solid iron reacts with copper (II) nitrate. Determine the products, balance the chemical equation and calculate the theoretical yield of the product containing iron. Assume iron will form Fe²+ ions when it reacts.

97.3 grams of iron reacts with 126 grams of silver acetate. Determine what products are formed, balance the chemical equation, determine the limiting reactant and calculate the theoretical yield, in grams, of the product containing iron. (When iron creates a bond it will have a charge of +2)

33.4 grams of aluminum undergoes a synthesis reaction with liquid bromine producing aluminum bromide Write the reaction equation, balance, and calculate the mass of aluminum bromide that is produced if all 33.4 grams of aluminum are consumed during the reaction. Round your answer to 3 significant figures.

1.000 mol of CH3CH₂OH gas is combusted with 2.000 mol of O₂ gas in a container of constant volume and temperature and the pressure increases from 1.500atm to 1.551atm. What is the % yield?

1. Describing a substance without using numbers 2. The exactness of a measurement to the accepted value 3. Condition in an experiment that is measured or controlled 4. Closeness of measurements of an object to one another 5. Describing a substance using numbers and measurements A accuracy B precision C qualitative D quantitative E variable

Convert the following statement into a yes-no question: The League of Women Voters provides information about elections. Does the League of Women Voters provide information about elections? Did the League of Women Voters provide information about elections? Do the League of Women Voters provide information about elections? Does the League of Women Voters provides information about elections?

What mass of chromium would be produced from the reaction of 57.0 g of potassium with 199 g of chromium(II) bromide according to the following reaction? b) Which reactant is in excess and how many grams of this reactant are left over?

What is the molarity of a solution that contains 41.0 g of ZnCl₂ dissolved in 3.00 L of solution?

Phosphine, PH3(g), combusts in oxygen gas to form water vapor and solid tetraphosphorus decaoxide. Express your answer as a balanced chemical equation. Identify all of the phases in your answer.

A solution is made by mixing equal volumes of 0.200 M HC₂H3O2 and 0.400 M NaC₂H3O2. Which of the following correctly describes what occurs if a small amount of HCI (aq) or NaOH (aq) is added? If HCI (aq) is added, the pH will increase only slightly because the Cl- ions will react with C₂H3O2 ions. If NaOH (aq) is added, the pH will decrease only slightly because the OH- ions will react with HC₂H3O2. If NaOH (aq) is added, the pH will increase only slightly because the OH ions will react with the C₂H3O2- ions. If HCI (aq) is added, the pH will decrease only slightly because the H+ ions will react with C₂H3O2 ions.

A metal has a work function (also called binding energy) of 5.98 x 10-19 J. Which is the longest wavelength that could cause emission of electrons? Insert your answer in decimal notation, rounded to three significant figures.

An unknown solution gives a yellow-green flame test, and a white precipitate with ammonium carbonate, ammonium phosphate, and ammonium sulfate. The halide test produces a yellow-orange color in the upper hexane layer. Identify (a) the alkali or alkaline earth element, and (b) the halide present in the unknown solution.

What fraction of the ox particles in Rutherford's gold foil experiment are scattered at large angles? Assume the gold foil is two layers thick, as shown in the figure, and that the approximate diameters of a gold atom and its nucleus are 1.6 Å and 1.2 x 10^-4 A, respectively. Hint: Calculate the cross-sectional area occupied by the nucleus as a fraction of that occupied by the atom. Assume that the gold nuclei in each layer are offset from each other. Express your answer to two significant figures.

A certain metal M forms a soluble sulfate salt MSO4. Suppose the left half cell of a galvanic cell apparatus is filled with a 2.00 M solution of MSO, and the right half cell with a 10.0 mM solution of the same substance. Electrodes made of M are dipped into both solutions and a voltmeter is connected between them. The temperature of the apparatus is held constant at 35.0 °C. Which electrode will be positive?

When 50.0 mL of 1.0 mol/L hydrochloric acid is neutralized completely by 75.0 mL of 1.0 mol/L sodium hydroxide in a coffee-cup calorimeter, the temperature of the total solution changes from 20.2 °C to 25.6 °C. Determine the quantity of energy transferred, q, and state whether the reaction was endothermic or exothermic. [ans: 2800 J; exothermic)

A 2.57 L sample of O₂ has a measured pressure of 920 mmHg and temperature of 30°C. a) How many moles of gas are present in the sample? b) Would you expect the answer to be higher, lower or the same for H₂ gas at same conditions in the same 2.57 L container? Explain.

How many types of orbitals are there in the shell with n=3 in an atom?

Calculate the heat change in kilojoules for condensation of 175 g of steam at 100 °C. Express your answer as a positive value using three significant figures and include the appropriate units.

An acetaminophen suspension for infants contains 80 mg/ 0.80 mL suspension. The recommended dose is 15 mg/kg body weight. How many mL of this suspension should be given to an infant weighing 14 lb? (Assume two significant figures.)

Assertion (A): Every state is sovereign; it has supreme and absolute power within its territory and can decide its foreign and domestic policies. Reason (R): For ages, the idea of a state's sovereignty has been closely associated with the concept of the state's ability to ensure the welfare and well-being of its citizens. Which of the following is TRUE for the above statements? Both (A) and (R) are true, but (R) is not the correct explanation of A. Both (A) and (R) are true, and (R) is the correct explanation of A. A is false, and (R) is true.

The process of causing matter to move against an opposing force is potential energy kinetic energy thermal energy work

How many μm are in 18.4 mm? 1.84 x 10^4 μm. 1.84 x 10¹ μm 1.84 x 10^-4 μm 1.84 x 10^-5 μm

TUTOR Empirical Formulas. weight percents relative moles of each element mole ratios of the elements empirical formula Step 1 Assume 100 g of sample. The mass percent of each element can therefore be used as a mass, in grams. Calculate the amount of C present (in moles) in the 100-g of sample. Calculate the amount of H present (in moles) in the 100-g of sample. Calculate the mass precent of O by difference. %0 = 100 (%C + %H) Use this to calculate the amount of O present (in moles) in the 100-g of sample. Step 2 Compare the amounts (in moles) of the three elements. Calculate mole ratios by dividing the amount (mol) of each by the amount (mol) of the element present in the smallest amount. Step 3 Use the mole ratios to determine the empirical formula. The relative amounts (mol) present correspond with the relative number of atoms in the formula. If the ratios are not integers, convert them into improper fractions. For example, 1.5 becomes 1 1/2 and then 3/2. Likewise, 2.33 becomes 2 1/3 and 7/3. Similarly, 1.6 would be 1 3/5, or 8/5. Then the numerators and denominators of the fractions give relative whole numbers of atoms. For example, 2 1/3 is 7/3, which gives a ratio of atoms of 7 to 3. An alcohol is 70.57 % C and 5.935 % H by mass. The rest is oxygen. What is the empirical formula of the alcohol? Enter the elements in the order C, H, and then O.

2. During the mid-20th Century, crackers were often stored in special tin containers that included a glass vial in their lids. The glass vial contained a dehydrated hydrate that would absorb moisture from the air as it rehydrated in order to keep the crackers from going stale. The most commonly used hydrate was epsom salts but they also included an additional hydrate like cobalt (II) chloride that would change colors as it went from being dehydrated to hydrated. When you heat the vial the water in the salts evaporates, so the cracker keeper can work again. I Why do you think that an indicator like cobalt (II) chloride was included in the vial?

The daily dose of ampicillin is 115 mg/kg of body weight. If you give 1.525 g of ampicillin to a patient, what is the patient's weight in pounds? (2.2 pounds = 1 kg). Use 4 significant figures in your answer.

Low-density lipoprotein (LDL) is a type of cholesterol that is often known as "bad cholesterol". Find the volume (cm³) of 0.815 g of LDL if the density is 0.767 g/cm³.

12.. Before performing the vacuum filtration, one should check that the hoses are _____ walled or they will collapse; that the filtering flask is _____ (to be able to recover the sample if it goes through with the mother liquor, and free of or it may shatter when the vacuum is applied,

What volume of bromine trifluoride is required to produce 63.5 liters of fluorine gas according to the following reaction? (All gases are at the same temperature and pressure.) bromine trifluoride (g) → bromine (g) + fluorine(g) _____ liters bromine trifluoride

A perfect cube of aluminum metal was found to weigh 37.4 g. The density of aluminum is 2.70 g/mL. What are the dimensions of the cube? Show all calculations and how you derived the answer.

A student placed a sample of a food coloring that contains a mixture of a blue dye and a red dye at the top of a chromatography column filled with a nonpolar stationary phase. When water is poured through the column, two bands of colors are seen in the column, as shown in the diagram above. A student collects a sample of the blue dye from the column in a cuvette. Which of the following is least useful to determine the concentration of the sample using a spectrophotometer set at 640 nm? The volume of the sample The path length of the cuvette The absorbance of the dye at 640 nm The molar absorptivity of the dye at 640 pm

A 0.4419 g sample of a pure soluble chloride compound is dissolved in water, and all of the chloride ion is precipitated as AgCl by the addition of an excess of silver nitrate. The mass of the resulting AgCl is found to be 0.6082 g. What is the mass percentage of chlorine in the original compound? %

A student determines the iron (II) content of a solution by first precipitating it as iron(II) hydroxide, and then decomposing the hydroxide to iron(II) oxide by heating. How many grams of iron(II) oxide should the student obtain if her solution contains 58.0 mL of 0.540 M iron (II) nitrate?

Balanced chemical equation 2 Cs H18 (g) + 25 O2 (g)→16 CO2 (g) +18 H₂O(g) How many moles of water are produced in this reaction?

Hot dogs are mostly protein, fat and water. After removing the water from a hot dog it weighs 100 grams. The label says "80% fat-free" by weight. How many calories come from fat? 720 calories 320 calories 180 calories 900 calories 90 calories None of these options is correct.

Which one of the following is correct concerning flaxseed? It contains lignans which have possible anti-cancer effects. It is low in fiber. None of these statements is correct. It is not safe for human consumption. It contains only omega-6 fats. It has a constipating effect.

Use scientific notation to express the number 0.013562 to: 1) one significant figure 2) two significant figures 3) three significant figures 4) four significant figures 5) five significant figures

Dimensional analysis is: based on the principle that units are unnecessary in chemistry based on the principle that the units in an equation can be treated like numbers based on the principle from physics that units should be derivatives based on the principle that all units are the same

A solution contains both Fe²+ and Fe³+ ions. 25.0 ml of this solution required 45.0 ml of 0.01 M acidified permanganate solution. In a separate analysis 25.0 ml of the original solution is treated with Zn powder which reduces Fe³+ into Fe²+ and it then required 3.76 ml of 0.2 M acidified KMnO4 solution to reach the end point. Determine the molarity of Fe³+ is the original solution.

A solution contains both Fe2+ and Fe3+ ions. 25.0 ml of this solution required 45.0 ml of 0.01 M acidified permanganate solution. In a separate analysis 25.0 ml of the original solution is treated with Zn powder which reduces Fe3+ into Fe2+ and it then required 3.76 ml of 0.2 M acidified KMnO4 solution to reach the end point. Determine the molarity of Fe3+ is the original solution.

Perform the following calculation, and choose the correct result that is rounded to the appropriate number of significant figures. NOTE: Treat all ambiguous zeroes (trailing zeroes before an implied decimal point) as NOT significant. [(0.5487) + (1.886 × 10¹)]/ [(9.648) (1.19 x 10¹)] -8.6x10⁰ -9x10⁰ -8.62x100 -8.618x10⁰ -8.61843x10⁰

For each of the mathematical expressions given: 1. Tell the correct number of significant figures for the answer. 2. Evaluate the mathematical expression using correct significant figures in the result. 485 / 9.231 2.17 + 4.32 + 401.278 + 21.826 452 x 6.2 / 34.3 2.46 × 2 15.467 - 9.23 10.4+3.75 + 274.6

To answer this question, you have to do some research or read the relevant chapter in the textbook. The mole concept is related to everyday chemistry. For this exercise, you are going to calculate the number of molecules or atoms. Identify one food item, find out what elements or compounds are in this item. Explain how you would calculate the number of molecules or atoms of your interest. Respond others having a difficult time with calculation.

Upon electrification, hydrogen produces a characteristic line spectrum consisting of four lines in the visible region of the electromagnetic spectrum. The light emitted in different regions of the visible spectrum corresponds to transitions from the third (n = = 3), fourth (n = 4), fifth (n = 5), or sixth (n = 6) energy level down to the second (n = 2). Which transition corresponds to the red line in the hydrogen spectrum? n=2 -> n=3 n=2 -> n=6 n=3 -> n=2 n=4 -> n=2 n=6 -> n=2

How many mg are in 6.2 kg? Use two significant figures in your answer.

People with lactose intolerance cannot digest _____ which eventually results in the production of _____. milk sugar, hydrogen gas None of these options are correct. sugar in beets, hydrogen gas fava beans, carbon dioxide gas cellulose, several bowel gases fava beans, methane gas

Which of the following changes represents a physical change, rather than evidence of a chemical reaction? When a piece of zinc metal is placed in a solution of HCI, bubbles begin to form, and the zinc begins to dissolve. When solid ammonium carbonate, (NH 4)2CO3, is heated, the solid disappears, and gaseous ammonia (NH3), carbon dioxide (CO2), and water (H2O) are formed. When dry ice (solid CO2) is allowed to stand at room temperature, gaseous CO2 is formed. When a solution of KI is mixed with a solution of Pb(NO 3)2, a yellow solid is formed. When a piece of copper wire is placed in a solution of AgNO3, a silvery solid begins to form on the surface of the wire, and the solution turns blue.

A 5.05 g sample of quartz (SiO 2) contains 2.36 g of silicon. What are the percentages of silicon and oxygen in quartz? 53.3% Si and 46.7% 46.7% Si and 53.3% 29.9% Si and 70.1% 70.1% Si and 29.9% 46.7% Si, and insufficient information to calculate %

4) Calculate the pH of a solution prepared by dissolving 0.150 mol of benzoic acid and 0.300 mol of sodium benzoate in water sufficient to yield 1.00 L of solution. The Ka of benzoic acid is 6.30 x 10-5 A) 2.516 B) 4.195 C) 4.502 D) 10.158 E) 3.892

Select the substance below which is a compound. O NO Olr Ni = Co Rf