Practical Detection Questions and Answers

What would happen to the pressure inside a sealed syringe if the temperature was increased from 500 K to 1000 K? The gas inside the syringe would liquify The pressure would increase The pressure would decrease The pressure would remain the same

What volume (mL) of 0.0829 M phosphoric acid can be neutralized with 144 mL of 0.361 M sodium hydroxide? 1880 12.9 627 1600 209

Propenoic acid, C3 H4 O2, is a reactive organic liquid that is used in the manufacturing of plastics, coatings, and adhesives. An unlabeled container is thought to contain this liquid. A 0.270-g sample is combusted to produce 0.172 g of water and 0.208 g of carbon dioxide. Calculate the experimental mass % of C and H in the unknown liquid used in the experiment. Express your answers, separated by commas, to three significant figures.

Write the formulas for the compounds given below. a) mercury (III) bisulfite b) hydrophosphoric acid c) gold (V) chlorite d) trinitrogen decoxide e) zinc nitride

Draw the Lewis symbol for krypton. Draw the Lewis dot structure for krypton. To change the symbol of an atom, double-click on the atom and enter the letter of the new atom.

How many electrons, protons, and neutrons are there in an atom of 244 Pu? protons neutrons electrons

Which of the following examples below could be used to summarize the results of scientific experiments? graphing experimental results drawing a picture forming a hypothesis asking questions creating a visual model

A chemist must prepare 550. ml. of 5.00 µM aqueous mercury(II) iodide (Hg1₂) working solution. She'll do this by pouring out some 58.7 aqueous mercury(II) iodide stock solution into a graduated cylinder and diluting it with distilled water. Calculate the volume in mL of the mercury(II) iodide stock solution that the chemist should pour out. Round your answer to 3 significant digits.

What is the maximum number of electrons possible in the shell with n = 3 in an atom?

Which of the following elements are nonmetals? (Z= atomic number) Choose all that apply. Cs (Z = 55) Kr (Z=36) Cr (Z=24) Ar (Z = 18) None of the Above

The density of pure silver is 10.5 g/cm³ at 20°C. If 9.50 g of pure silver pellets is added to a graduated cylinder containing 10.2 mL of water, to what volume level will the water in the cylinder rise?

State whether the kinetic energy of the underlined object increases or decreases as a result of the change described. an air plane takes off a tennis ball is served a golf ball lands on a green

The world record for the hundred meter dash is 9.58 s. What is the corresponding average speed in units of m/s, km/h, ft/s, and mi/h? a. In units of m/s? b. In units of km/h? c. In units of ft/s? d. In units of mi/h? e. At this speed, how long would it take to run 2.00 × 10² yards?

Which of the following is the correct name for the compound with formula Ca3P₂? (A) Tricalcium diphosphorus (B) Calcium phosphite (C) Calcium phosphate (D) Calcium diphosphate (E) Calcium phosphide

How many C atoms were needed to make 16 molecules of Mo(CO),(CHN);? How many TOTAL atoms are needed to make 16 molecules of Mo(CO),(CHN),? How many moles of atoms came together to make 0.5 moles of Mo(CO),(CHN);? Given the ion C₂0, what species would you expect to form with each of the following ions?

For the following reaction, 0.119 moles of calcium hydroxide are mixed with 0.339 moles of hydrochloric acid. calcium hydroxide (aq) + hydrochloric acid (aq) → calcium chloride (aq) + water (2) What is the formula for the limiting reagent? What is the maximum amount of calcium chloride that can be produced?

If the length, width, and height of a box are 9.25 cm, 5.00 cm and 3.00 cm, respectively, what is the volume of the box in units of milliliters and liters? (a) How many mL will the box contain? (b) How many L will the box contain?

A sample of Mg weighs 13.3 grams. Will a sample of B that contains the same number of atoms weigh more or less than 13.3 grams? (more, less): Calculate the mass of a sample of B that contains the same number of atoms. grams of B

Carry out the following mathematical operation: 20.684 / 13.84 Identify the number of significant figures for the answer of this operation. What is the result of this calculation (when reported to the correct number of significant figures)? Carry out the following mathematical operation: 20.684-13.84 b. Identify the number of decimal places for the answer of this operation. What is the result of this calculation (when reported to the correct number of decimal places)?

Complete and balance the following redox reaction in basic solution Zn(s) →→→ Zn(OH)²(aq) + H₂(g)

Balance the following redox reaction in basic condition. (b) After balancing the equation, indicate which species is a reducing agent and an oxidizing agent. Al (s) + MnO, (aq) → MnO₂ (s) + Al(OH)4 (aq)

Example #2: Calculate the enthalpy of the following chemical reaction: CS2(l) + 3O2(g) ---> CO2(g) + 2SO2(g) Given: C(s) + O2(g) ---> CO2(g) ΔH = -393.5 kJ/mol S(s) + O2(g) ---> SO2(g) ΔH = -296.8 kJ/mol C(s) + 2S(s) ---> CS2(l) ΔH = +87.9 kJ/mol

During its orbit, the Earth's minimum distance from the sun is approximately 148 million kilometers. Which of the following correctly represents this number in scientific notation? 1.48 x 10^8 1.48 x 10^4 1.48 x 10^-7 148,000,000

Calculate the standard molar enthalpy change of each equation by giving the step-by-step solution. 1) H2(g) + 1/2 O2(g) ==> H2O(I) ΔH= -286 kJ 2) HCl(aq) + N ==> aOH(aq) + NaCl(aq) + H2O(I) + 58 kJ 3) C6H12O6 + 6H2O ==> 6H2 + 6CO2 ΔH= -627 kJ 4) 6CO2 + 6H2O + 2803 kJ ==> C6H12O6 + 6H₂O 5) CaCO3 +178kJ ==> CO2 + CaO

A student places 5.3 g of a solid substance into a test tube and heats it up. After heating it (and then letting it cool), they weigh the substance again. To their surprise, the mass is now 3.6 g. In a few sentences, explain to the student which type of reaction this likely was, and also explain how this relates to mass conservation. Explain to the student why they experiences a decrease in mass.

A compound with a molar mass of 544.0 g/mol is made up of 26.5 grams Carbon, 2.94 grams Hydrogen, and 70.6 grams Oxygen. What is its empirical and molecular formula?

You have a 1.00-mole sample of water at -40.°C and you heat it until you have gaseous water at 130°C. Calculate q for the entire process. Use the following data. Specific heat capacity of ice=2.03 J/*C-g Specific heat capacity of water =4.18 J/*C-g Specific heat capacity of steam=2.02 J/*C-g H₂O(s)→ H₂O(l) AH fusion 6.02 kJ/mol (at 0°C) H₂O(1)→ H₂O(g) AH vaporization = 40.7 kJ/mol (at 100. C)

In the laboratory a student finds that it takes 124 Joules to increase the temperature of 12.2 grams of solid sulfur from 23.4 to 38.1 degrees Celsius. The specific heat of sulfur calculated from her data is ___ J/g°C.

Enter the correct name for Ba(C₂H₂O₂)₂

Number of correct statement among the following is: (a) When the pH of rain water drops to 6.5, it is called acid rain. (b) The acidity of soil can be reduced by adding powdered limestone. (c) Peroxyacetal nitrate act as powerful eye irritant. (d) Bacteria like escherichia coli causes gastrointestinal disease. (e) Clean water should have BOD value of 17 ppm or more. (f) The prescribed upper limit concentration of lead in drinking water is about 50 ppm

Consider the given equilibrium H₂O(s) ---H₂O(1) Backward shifting of equilibrium is favoured by High temperature, Low pressure High temperature, High pressure Low temperature, Low pressure Low temperature, High pressure

Vacuum filter using the Buchner funnel, rinse the mortar with 5 ml of methanol and add the rinsing to the Buchner funnel. Wash the residue in the funnel with 25 ml of pet ether (a mixture of pentanes)

What volume of a 0.354 M hydrochloric acid solution is required to neutralize 17.9 mL of a 0.133 M sodium hydroxide solution?

In the laboratory, a student dilutes 26.6 mL of a 8.57 M hydrochloric acid solution to a total volume of 125.0 mL. What is the concentration of the diluted solution?

According to the following reaction, how many grams of water will be formed upon the complete reaction of 26.8 grams of hydrogen peroxide (H₂O₂)? hydrogen peroxide (H₂O₂) (aq) →→→water (1) + oxygen (g)

Ethanol, C₂H5OH, can be converted to acetic acid (the acid in vinegar), HC₂H3O2, by the action of sodium dichromate in aqueous sulfuric acid according to the following equation. 3C₂H5OH (aq) + 2Na₂Cr₂O7 (aq) + 8H₂SO4 (aq) + 3HC₂H3O2 (aq) + 2Cr₂(SO4)3 (aq) + 2Na₂SO4 (aq) + 11H₂O In one experiment, 24.5 g of C₂H5OH, 86.1 g of Na₂Cr₂O7, and an excess of sulfuric acid were mixed, and 26.6 g of acetic acid (HC₂H30₂) was isolated. Calculate the theoretical yields of HC₂H3O2.

If a 58.3 g sample of the liquid 1-iodoheptane has a volume of 42.3 mL, what is the density of the compound in g/mL? The liquid 1-iodoheptane is insoluble in water. If approximately equal volumes of water and 1- iodoheptane were mixed in a separatory funnel, would the water layer end up on the top or on the bottom? (Density of water is 1.00 g/mL.)

Specify the number of protons, neutrons, and electrons in the neutral atom copper-64. Enter your answers as integers separated by commas.

Which of the following best categorizes the idea that the rate of a reaction is dependent on temperature because the rate ultimately depends on the frequency of collisions between reacting species (atoms, molecules, etc.)? A) scientific law B) theory C) hypothesis D) observation

After loading the liquid sample into your distillation apparatus, what else needs to be added to the round bottom flask before distillation can be performed?

After your fourth fraction, you have about 0.5 mL left in the round bottom. In order to get your last fraction, you must run the distillation till every last drop of liquid has become vapor A True B False

An analytical chemist weighs out 0.067 g of an unknown monoprotic acid into a 250 mL volumetric flask and dilutes it to the mark with distilled water. He then titrates this solution with 0.1900 M NaOH solution. When the titration reaches the equivalence point, the chemist finds he has added 3.6 mL of NaOH solution. Calculate the molar mass of the unknown acid.

Na₂CO3(aq) +CaCl₂(aq) -> 2 NaCl(aq) + CaCO3(s) Calculate the volume (in mL) of 0.200 M Na₂CO3 needed to produce 2.00 g of CaCO3(s) There is an excess of CaCl2 Molar mass of calcium carbonate = 100.09 g/mol Volume of sodium carbonate = ___ mL

Which of the following statement is not correct? A. Pure nitric acid is a light yellow liquid B. Nitric acid with water forms an azeotropic mixture containing 98% of acid C. Nitric acid when mixed with concentrated H₂SO4 produces nitronium ion D. Covalent nitrates are less stable than ionic nitrates

Ethanol has a molecular mass of 46 and a density of 0.79 g/mL. A bottle of wine has an alcohol (ethanol) concentration of 12% v/v. What is the molar concentration of ethanol in this bottle? Give your answer to 2 decimal places.

A U.S. secret weapon in the Pacific campaign was its possession of the atomic bomb from 1941 on. its alliance with the Soviets. a code-breaking operation known as Magic. massive military aid from Korea and Vietnam. an almost three-to-one advantage in aircraft carriers.

When comparing ¹HNMR and 13CNMR spectrum, they will differ in which of the following general aspects? ► View Available Hint(s) O Number of scans taken to produce the spectrum O standard used O Range of the spectrum O Splitting patterns O Integration O All are differences except the standard used.

Consider two gases, A and B, each in a 1.0-L container with both gases at the same temperature and pressure. The mass of gas A in the container is 0.34 g and the mass of gas B in the container is 0.48 g. (20points) a. Which gas sample has the most molecules present? Explain. b. Which gas sample has the largest average kinetic energy? Explain. c. Which gas sample has the fastest average velocity? Explain. d. How can the pressure in the two containers be equal to each other since the larger gas B molecules collide with the container walls more forcefully?

The rate of effusion of a particular gas was measured and found to be 24.0 mL/min. Under the same conditions, the rate of effusion of pure methane (CH4) gas is 47.8 mL/min. What is the molar mass of the unknown gas? (5points)

A certain liquid has a vapor pressure of 92.0 Torr at 23.0 °C and 362.0 Torr at 45.0 °C. Calculate the value of AHp for this liquid. AH= Calculate the normal boiling point of this liquid. boiling point: kJ/mol 'C