Practical Detection Questions and Answers

A sample of krypton gas occupies a volume of 9.50 L at 67.0°C and 376 torr. If the volume of the gas sample is decreased to 7.66 L, while its temperature is increased to 118.0°C, the resulting gas pressure will be _ torr.

For the following reaction, 15.3 grams of sulfur are allowed to react with 20.5 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?

For this reaction, 24.9 g iron reacts with 6.05 g oxygen gas. iron (s) + oxygen (g) ---> iron(II) oxide (s) What is the maximum mass of iron(II) oxide that can be formed? What is the FORMULA for the limiting reagent? What mass of the excess reagent remains after the reaction is complete?

For the following reaction, 2.99 grams of methane (CHA) are allowed to react with 32.4 grams of carbon tetrachloride. methane (CH4)(g) + carbon tetrachloride (g) ---> dichloromethane (CH₂Cl₂)(g) What is the maximum mass of dichloromethane (CH₂Cl₂) that can be formed? What is the FORMULA for the limiting reagent? What mass of the excess reagent remains after the reaction is complete?

Lin Zexu was the driving force behind the Meiji restoration. in charge of stopping the opium trade in China. a leader of the Self-Strengthening Movement. the leader of the Taiping rebellion. the last Qing emperor in China.

Lead(II) oxide from an ore can be reduced to elemental lead by heating in a furnace with carbon. PbO(s) + C(s)→ Pb(l) + CO(g) Calculate the expected yield of lead if 50.0 kg of lead oxide is heated with 50.0 kg of carbon.

At 25° C, a solution containing 1.24 g of sucrose, dissolved in 3 mL of water, was placed in a polarimeter cell that has a tube length of 10 cm. The observed rotation of the solution was +39.0°. What is the specific rotation of this solution?

A metal sample weighing 43.5 g and at a temperature of 100.0 °C was placed in 39.9 g of water in a calorimeter at 25.1 °C. At equilibrium the temperature of the water and metal was 33.5 °C. a. What was ΔT for the water? (ΔT = Tfinal - Tinitial) b. What was ΔT for the metal? c. Using the specific heat of water (4.184 J/g °C), calculate how much heat flowed into the water? d. Calculate the specific heat of the metal.

Show the molecular equation, ionic equation and the net ionic equation for the following equations. If all species are spectator ions, please indicate that no reaction takes place. Note: Be sure the original equation is balanced before proceeding! 1. AgNO3(aq) + KCl(aq) → AgCl(s) + KNO3(aq) 2. Mg(NO3)2(aq) + Na₂CO3(aq) → MgCO3(s) + NaNO3(aq) 3. strontium bromide (aq) + potassium sulfate(aq) → strontium sulfate(s) + potassium bromide (aq) 4. manganese (II) chloride (aq) + ammonium carbonate(aq) → manganese(II)carbonate(s) + ammonium chloride (aq) 5. chromium(III)nitrate(aq) + iron(II)sulfate(aq) → chromium(III)sulfate(aq) + iron(II)nitrate(aq)

With respect to the Na+/K+ ATPase, it is not an antiport it helps balance a cell's osmotic pressure it is electroneutral it uses a proton gradient for energy all of the above are true none of the above are true

Predict the number of signals expected in the H NMR spectrum of each molecule below Ignore signal splitting.

A certain reaction with an activation energy of 165 kJ/mol was run at 535 K and again at 555 K. What is the ratio of f at the higher temperature to f at the lower temperature? Express your answer numerically using one significant figure.

The activation energy of a certain reaction is 35.2 kJ/mol. At 24 °C, the rate constant is 0.0160s-¹. At what temperature in degrees Celsius would this reaction go twice as fast? Express your answer with the appropriate units.

A compound is found to contain 14.87% phosphorus and 85.13% chlorine by mass. What is the empirical formula for this compound?

Shown below are the spectra (labeled A and B) for the reactant and product in a bromination reaction. One spectrum shows C3H6Br2O and the other one shows C3H6O. Identify which spectra is which, draw the two structures for the reactant and product and then explain which peaks in the NMR spectra correspond to the hydrogens in the structure.

During formation of photochemical smog, methane react with ozone to form an aldehyde. How many moles of methane will be oxidized by 4 mole of ozone?

Find the element phosphorus, P, on the periodic table. a. What is the average atomic mass of phosphorus? b. What is its atomic number? c. Predict which isotope you would find in greatest abundance for phosphorus.

How many ATOMS of sulfur are present in 2.76 grams of sulfur dichloride ? How many GRAMS of chlorine are present in 9.76x1022 molecules of sulfur dichloride?

How many Fe atoms are there in 4.67 moles of Fe? ____atoms

A compound is found to contain 26.96 % sulfur, 13.45% oxygen, and 59.59 % chlorine by mass. What is the empirical formula for this compound? To answer the question, enter the elements in the order presented above.

A compound having an approximate molar mass of 253.0-258.0 g has the following percentage composition by mass: Determine the empirical and molecular formulas of the compound.

How many grams of Ti are there in a sample of Ti that contains 4.06×1023 atoms?

Article: How Soddy's nightmare about the future of radioactive isotopes realized? The use of radioactive isotopes to quickly end World War II. The use of radioactive isotopes to provide energy. The use of radioactive isotopes to model climate change. The use of radioactive isotopes to be used in medicine.

Many chromate (CrO₂) salts are insoluble, and most have brilliant colors that have led to their being used as pigments. Choose the correct net ionic equation for the reaction of Sr²+ with a chromate ion. Sr²+ (aq) + 2CrO4²(aq) → S-(CrO4)2 (s) Sr²+ (aq) + CrO² (aq) → SrCrO4(s) 2Sr²+ (aq) + CrO₂ (aq) → Sr₂ CrO4(s) Sr²+ (aq) + CrO4² (aq) → SrCrO₂ (aq)

Consider the following compounds. Which is/are insoluble? Select all that apply. Ba(OH)₂ NaOH CuOH Hg(OH)₂ All of these None of these

Consider the following reaction: Al+3CuCl → AlCl3 + 3Cu Identify what main category of reaction it is. If possible, further categorize it into all other relevant types of reaction. Synthesis Decomposition Combustion Single Replacement Double Replacement Precipitation Acid-Base Oxidation-Reduction Gas Evolving Question Help: Message instructor Submit Question

A chemistry student must write down in her lab notebook the concentration of a solution of sodium hydroxide. The concentration of a solution equals the mass of what's dissolved divided by the total volume of the solution. Here's how the student prepared the solution: The label on the graduated cylinder says: empty weight: 8.5 g She put some solid sodium hydroxide into the graduated cylinder and weighed it. With the sodium hydroxide added, the cylinder weighed 83.15 g. She added water to the graduated cylinder and dissolved the sodium hydroxide completely. Then she read the total volume of the solution from the markings on the graduated cylinder. The total volume of the solution was 97.85 mL. What concentration should the student write down in her lab notebook?

Calculate the percent yield in the photosynthesis reaction by which carbon dioxide is converted to sugar if 7.03 g of carbon dioxide yields 3.92 g of C6H12O6. The equation is 6 CO₂ + 6 H₂O → C6H12O6 +6 02.

The first step in the Ostwald process for manufacturing nitric acid is the reaction between ammonia and oxygen described by the equation 4NH3 +502 4NO + 6H₂O. Use this equation to answer the following three questions. 19. How many moles of ammonia will react with 95.3 moles of oxygen? 20. How many moles of nitrogen monoxide will result from the reaction of 2.89 moles of ammonia? 21. If 3.35 moles of water is produced, how many moles of nitrogen monoxide will also be produced? 22. Magnesium hydroxide is formed from the reaction of magnesium oxide and water. How many moles of magnesium oxide are needed to form 0.884 moles of magnesium hydroxide, when the oxide is added to excess water?

Determine the number of grams of C4H10 that are required to completely react to produce 8.70 mol of CO₂ according to the following combustion reaction: 2 C4H10(g) + 13 O₂(g) → 8 CO₂(g) + 10 H₂O(g)

Which of these sentences about asking or giving advice correct (page 193)? A) You should not to pack your suitcase now. B) You should not be packing your suitcase now. C) You should not packing your suitcase now. D) You should not packed your suitcase now.

Determine the number of grams of HCI that can react with 0.750 g of Al(OH)3 according to the following reaction Al(OH)3(s) + 3 HCl(aq) → AICI3(aq) + 3 HO(aq)

Limestone stalactites and stalagmites are formed in caves by the ollowing reaction: Ca²+ (aq) + 2HCO3(aq) → CaCO3(s) + CO2(g) + H₂O(1) f 1 mol of CaCO3 forms at 298 K under 1 atm pressure, the reaction performs 2.49 kJ of P-V work, pushing back the atmosphere as the gaseous CO₂ forms. At the same time, 38.85 J of heat is absorbed from the environment. What is the value of AH for this reaction? Express your answer using four significant figures

The addition of chromic acid or chromate is a qualitative test for alcohols as the reaction causes a color change. However, not all alcohols react with chromic acid or chromate. Determine whether the named alcohol will react with chromic acid or chromate to cause a color change. 3-hexanol Choose... 3-ethyl-3-pentanol Choose.... 1-butanol Choose... 2-pentanol Choose...

Calculate the mass of water produced when 6.51 g of butane reacts with excess oxygen.

Pressurized metal gas cylinders are generally used to store commonly used gases in the laboratory. At times it can be easier to chemically prepare occasionally used gases. For example, nitrogen monoxide, NO(g), can be prepared in the lab using the following chemical reaction: 3Cu(s) + 8HNO3(aq) → 2NO(g) + 3Cu(NO3)2(aq) + 4H₂O(1) If 5.0 g of copper metal was added to an aqueous solution containing 2.5 moles of HNO3, how many moles of NO(g) would be produced, assuming a 100% yield? 0.042 mole NO 0.052 mole NO 0.062 mole NO

When elemental phosphorus, P4, burns in oxygen gas, it produces an intensely bright light, a great deal of heat, and massive clouds of white, solid phosphorus(V) oxide (P₂O5) product. Given these properties, it is not surprising that phosphorus has been used to manufacture incendiary bombs for warfare. Choose the unbalanced equation for the reaction of phosphorus with oxygen gas to produce phosphorus(V) oxide. P₂O5 (s)→ P4(s) + O2(g) P₂O5 (8) + P4 (8) → O2(g) P4(s) + O2(g) → P2O5 (8) P4(s) → P2O5 (8) + O2(g)

Nitrous oxide gas (systematic name: dinitrogen monoxide) is used by some dental practitioners as an anesthetic. Nitrous oxide (and water vapor as a by-product) can be produced in small quantities in the laboratory by carefully heating of ammonium nitrate. Choose the unbalanced chemical equation for this reaction. NH4NO3 (8) + H₂O(s) → N₂O(g) NH4NO3(s) + O2(g) → N₂O(g) NH4NO3(s) + N₂(g) → N₂O(g) + H₂O(g) NH4NO3(s) → N₂O(g) + H₂O(g)

A common demonstration in chemistry courses involves adding a tiny speck of manganese (IV) oxide to a concentrated hydrogen peroxide, H₂O2, solution. Hydrogen peroxide is unstable, and it decomposes quite spectacularly under these conditions to produce oxygen gas and steam (water vapor). Manganese (IV) oxide is a catalyst for the decomposition of hydrogen peroxide and is not consumed in the reaction. Choose the balanced equation for the decomposition reaction of hydrogen peroxide. H₂O₂ (aq) → 3H₂O(g) + O₂(g) 2H₂O₂ (aq) → 3H₂O(g) +20₂ (9) 2H₂O₂ (aq) → 2H₂O(g) + O₂(g) H,Oz(aq) → H_O(g)+Oz(g)

A student collected 88.0 mL of carbon dioxide at 28.00C and 730 torr. What volume of carbon dioxide would the student have at 28.00C and 760 torr?

Consider the following hypothetical acid-base reaction HOH + Y 2 OH + HY for which the transition state is represented as the reaction rate depends only on the concentration of HOH. the reaction is overall first order. the reaction is first order with respect to water. R = K[HOH][Y] Both C and D

A 0.5881 g sample of impure magnesium hydroxide is dissolved in 105.0 mL of 0.2047 M HCl solution. The excess acid then needs 19.85 mL of 0.1050 M NaOH for neutralization. Calculate the percent by mass of magnesium hydroxide in the sample, assuming that it is the only substance reacting with the HCl solution.

A sample of an unknown contains 30.4% nitrogen and 69.6% oxygen. What is the empirical formula for this compound?

Tartaric acid, H₂ C4 H4 O6, has two acidic hydrogens. The acid is often present in wines and precipitates from solution as the wine ages. A solution containing an unknown concentration of the acid is titrated with NaOH. It requires 21.65 mL of 0.2500 M NaOH solution to titrate both acidic protons in 40.00 mL of the tartaric acid solution. Write a balanced net ionic equation for the neutralization reaction.

Bronze is a solid solution of Cu(s) and Sn(s); solutions of metals like this that are solids are called alloys. There is a range of compositions over which the solution is considered a bronze. Bronzes are stronger and harder than either copper or tin alone. A 200.0-g sample of a certain bronze is 90.0% copper by mass and 10.0% tin. Which metal can be called the solvent, and which the solute? Tin is the solvent and copper is the solute. Copper is the solvent and tin is the solute. Copper is both the solvent and the solute. Tin is both the solvent and the solute.

Tartaric acid, H₂ C4H4O6, has two acidic hydrogens. The acid is often present in wines and precipitates from solution as the wine ages. A solution containing an unknown concentration of the acid is titrated with NaOH. It requires 21.65 mL of 0.2500 M NaOH solution to titrate both acidic protons in 40.00 mL of the tartaric acid solution. Write a balanced net ionic equation for the neutralization reaction.

A solution is made by mixing 13.0 g of Sr(OH)2 and 35.0 mL of 0.180 M HNO3. Calculate the concentration of NO3 ion remaining in solution.

Which orbital notation correctly represents the outermost principal energy level of a nitrogen atom in the ground state?

Calculate the energy (J) change associated with an electron transition from n=1 to n = 5 in a Bohr hydrogen atom. Specify if the energy is released or absorbed by the electron during this transition.

How do the calculations look like to prepare 210.0 ml of 0.25 M nitric acid solution from a 0.60 M nitric acid solution. a) How much of the 0.60 M nitric solution is needed? b) How much water will you need to add to make that solution?