CHE1111Lab Final

The energy of a photon of light is proportional to

Its frequency

The name for PbCl4 is _________________.

Lead (IV) chloride

The formula for sodium carbonate is

Na2CO3

Which of the following compounds represent the chemical formula for baking soda.

NaHCO3

The formula for sodium nitrite is

NaNO2

A student takes a solution containing a mixture Ba2+, Li+, and Ag+ ions and adds NO3- ions to the solution. Which of the following ions will form a precipitate in this solution? (Choose all that apply)

None of these

When constructing a calibration curve, what should be done with the non-linear portions of the curve at low and high concentrations.?

Points should be discarded since they are outside of the linear response region.

Which of the following metals forms only one type of ion

Rubidium Zinc

A student tells you that the name of the compound FePO4 is iron(IV) phosphate. Which of the following statements apply to this name?

The Roman numeral is incorrect

What should you use for semi-precise measurements of liquids?

Graduated cylinder

Which of the following would increase the absorption of a colored analyte in solution? (Choose all that apply)

Increase concentration of analyte. Increase pathlength

Choose the name-chemical formula that does not match

Iron (III) nitrate, Fe(NO2)3

The charge of the cation in V(NO3)5

+5

Calculate the heat (in Joules) involved in the process when 143 grams of water goes from a temperature of 13.6°C to 11.7°C. The specific heat capacity of water is 4.184 J/(g °C).

-1,137

Calculate the moles of NaOH present if 20.28 mL of a 0.369 M solution of NaOH are used in a titration. Do not enter units with your answer.

0.00748

A student performs a titration by dispensing a 2.86 M solution of NaOH from a buret. The student records the following data: Initial volume: 6.21 mL Final volume: 21.89 mL Calculate the moles of NaOH used in this titration

0.0448

A student titrates a sodium hydroxide solution against potassium hydrogen phthalate (HKC8H4O4, molar mass = 204.2 g/mol) in order to determine its molarity. HKC8H4O4 (aq) + NaOH (aq) → NaKC8H4O4 (aq) + H2O (l) The following data are recorded for the experiment: Mass of potassium hydrogen phthalate0.601 gramsInitial buret volume15.34 mLFinal buret volume30.21 mL Calculate the molarity of the NaOH solution. Do not enter units with your answer.

0.198

Calculate the molarity of a solution prepared by dissolving 8.02 grams of sodium bicarbonate to 241.2 mL of water.

0.396

Convert 30.00 grams of lithium hydrogen carbonate to moles of lithium hydrogen carbonate.

0.4412

You watched a video illustrating Part B of this experiment, where a standard solution of NaCl in water was prepared, and then its density was measured using a 50 mL volumetric flask. The volume of the solution in this flask can be reported at 50.00 mL. Use the information from the video to calculate the density of the 15% NaCl solution as measured in Trial 2 in units of g/mL. Report your answer to the correct number of significant figures, and do not include units in your answer.

1.103

You watched a video illustrating Part B of this experiment, where a standard solution of NaCl in water was prepared, and then its density was measured using a 50 mL volumetric flask. The volume of the solution in this flask can be reported at 50.00 mL. Use the information from the video to calculate the density of the 20% NaCl solution as measured in Trial 2 in units of g/mL. Report your answer to the correct number of significant figures, and do not include units in your answer.

1.135

A student adds 1.478 grams of salt to a beaker and then adds an additional 83.117 grams of water to the beaker. After stirring, the salt completely dissolves in the water. Calculate the % salt by mass of this solution. Do not round off your answers until the very end of the calculations. Report your answer to the correct number of significant figures, and do not include units or the % sign in your answer.

1.747

Calculate the molar mass of salicylic acid, C7H6O3.

138.118

Calculate the molar mass (in units of g/mol) for the compound P3Cl2. (Do not enter units with your answer.)

163.8

Consider the balanced reaction presented below. What volume (in mL) of 0.314 M KOH(aq) is needed to completely react 55.8 mL of 0.488 M H2SO4(aq)? H2SO4(aq) + 2KOH(aq) → 2H2O(l) + K2SO4(aq)

173

Draw the best Lewis structure for NO2+ (N is the central atom). What is the best estimate of the bond angle present around the N atom?

180 degrees

What volume of water (in mL) is needed to dissolve 1.41 grams of CH4O to form a solution with a CH4O molarity of 0.242 M?

182

Calculate the total number of valence electrons present in SO42−.

32

Calculate the molar mass (in g/mol) of Fe2(SO4)3. Do not enter units with your answer.

399.9

Calculate the mass (in grams) of Na2SO4 needed to prepare 653.0 mL of a 0.533 M Na2SO4. Do not enter units with your answer.

49.4

How many moles of oxygen are there present in 1.42 moles of barium sulfate?

5.68

A student measures 10.96 mL of a substance and finds that its mass is 65.2 grams. Calculate the density (in g/mL) of this substance. (Do not include units in your answer.)

5.95

Which piece of glassware should be used to make 50 mL of a standard solution with known concentration.

50ml volumetric flask

A 19.731 gram sample of a hydrated compound is heated until the water is removed through evaporation. The remaining material has a mass of 11.819 grams. Calculate the mass of water (in grams) that was present in the original sample. Do not enter units with your answer.

7.912

In absorption spectroscopy, an atom or molecule can [ Select ] a photon to promote an electron in a lower energy level to an excited energy level. The energy of the photon must be equal to[Select}

Absorb;energy;the band gap between the two energy levels.

A reaction is performed in water, and this causes 225 grams of water to go from a temperature of 12°C to 14°C. The specific heat capacity of water is 4.184 J/(g °C). The water____heat, which means that the reaction____heat. The reaction must be____and the sign of ∆Hrxn must be

Absorbed;released;exothermic;negative

Which of the following compounds are soluble in water? Choose all that apply.

AgNO3 K3PO4 Li2S CuCl2

What glassware should you use when measuring volume displacement?

Graduated cylinder

What is the slope of a calibration curve plotting absorbance vs. concentration?

Attenuation coefficient * Path length

Consider the compound BaSO3•2H2O The name for this compound is

Barium sulfite dihydrate

Which of the following formulas could be empirical formulas for a compound? Choose all that apply.

CH3 C3H9O C2H5 BaSO4

Calcium phosphate is one of the reagents use to make phosphoric acid. The chemical formula for calcium phosphate is

Ca3(PO4)2

Which of the following formulas is correct for the compound calcium oxide?

CaO

It is designed to accurately measure and deliver a specific volume of liquid.

Choose all the statements below that are correct about the piece of glassware shown here

It is designed to be directly heated.

Choose all the statements below that are correct about the piece of glassware shown here.

The Beer-Lambert law states that the absorbance of a species is proportional to its...

Concentration

The chemical formula of a compound containing Cu2+ and OH- is

Cu(OH)2

When using a calibration curve, what should be done if the instrument response for the unknown sample is higher than that of the largest standard solution?

Dilute the unknown sample and re-run, making note of the dilution factor.

20. 33.

Examine the glassware pictured below. Which of the following volumes below are reported to the correct number of significant figures if this piece of glassware was used to measure them? Choose all that apply.

Which of the following is completely transparent to UV light?

Fused quartz

Which of the following compounds is NOT an example of an ionic compound

GeCl4

Which of the following statements are true regarding glassware? Choose all that apply.

Glassware can be clamped in place to a stand to ensure that it does not tip over during an experiment. The volume of liquid should be read from the bottom of the meniscus. Glassware marked 'TD' should be used if a precise volume of liquid needs to be transferred to another container.

Another student performs the NaOH standardization as described in the previous problem, but they do not realize that the potassium hydrogen phthalate added to the solution is mixed with sodium chloride from a different experiment. (Sodium chloride does not react with sodium hydroxide.) The student performs the titration until a pale pink color is seen, and then calculates the molarity of the NaOH solution. How does the calculated NaOH molarity compare to the actual NaOH molarity?

The calculated NaOH molarity is larger than the actual NaOH molarity.

Consider the reaction below for the combustion of methane (CH4, which is the principal component of natural gas). Natural gas is a common fuel used to provide heat in homes as well as to heat water, and it is increasingly used as an alternative to coal for the production of electricity. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) + q Which of the following statements are correct?

The combustion of methane is exothermic, and the sign of ∆Hrxn is negative.

Consider samples of water and of ethanol that have equal masses. Which statement correctly describes the change in temperature when the same amount of heat is absorbed by the water and the ethanol samples? The specific heat capacity of water is 4.184 J/(g °C), and the specific heat capacity of ethanol is 2.30 J/(g °C).

The ethanol will have a larger increase in temperature than the water.

Which of the following statements is correct regarding the Lewis structure drawn below for N2H2?

This structure is incorrect because the octet rule for N is not satisfied.

What is used to DISPENSE a precise volume of liquid?

Volumetric pipette

You are given a solution that contains a mixture of Ag+ and Mg2+ ions. What anion (if any) could be added to separate the two cations? Briefly explain how you arrived at your answer.

You could add SO4 because this anion would make an insoluble solution when combined with Ag and a soluble solution when paired with Mg.

A student adds solid sodium bicarbonate to a beaker of water and stirs until the solid has dissolved. In this case, the sodium bicarbonate is the___ and the water is___

solute;solvent

What values should you record after acquiring a spectrum?

λmax and the absorbance at λmax

Which of the following values for the change in enthalpy of a reaction (∆Hrxn) and descriptions correctly describe an exothermic reaction? Choose all that apply.

∆Hrxn = −10 kJ, heat is released by the reaction to the surroundings ∆Hrxn = −10 kJ, heat is released by the reaction to the surroundings