Knewton Ch 4 Pt 2

The quantity of product that is physically measured at the end of a reaction is called: Select the correct answer below: theoretical yield actual yield percent yield fractional yield

The actual yield is the physical quantity of product that is actually measured at the end of a chemical reaction.

In a quantitative analysis, what is the term for the chemical species of interest? Select the correct answer below: analyte titrant solvent solute

analyte The term for the chemical species of interest in quantitative analysis is analyte.

The end point of a titration is defined as the volume of titrant added, while the equivalence point is the volume required for complete reaction with the analyte. By choosing the proper _____________, scientists can minimize the difference in these two numbers, allowing more accurate measurements in the lab. Select the correct answer below: titrant indicator solvent analyte

indicator A particular indicator is chosen because it is designed to change color very close to the equivalence point of a reaction, thus making the end point of a titration very close to the equivalence point.

What is the equivalence point of the titration? Select the correct answer below: the point where the concentrations of the analyte and the titrant are equal the point where the volumes of the analyte and the titrant are equal the point where a noticeable change in appearance occurs the point at which the volume of the titrant solution required for complete reaction with the analyte has been added

the point at which the volume of the titrant solution required for complete reaction with the analyte has been added

Titration analysis is a chemical technique where a(n) __________ of __________ concentration is used to determine the concentration or amount of __________ in a sample. Select the correct answer below: analyte, unknown, titrant titrant, unknown, analyte titrant, known, analyte analyte, known, titrant

titrant, known, analyte Titration analysis is a chemical technique in which a titrant of known concentration is used to determine the concentration or amount of analyte in a sample.

In the eighteenth century, why was potassium carbonate added to vinegar samples? Select the correct answer below: to create a precipitate to determine the "strength" of vinegar in vinegar samples to create bubbles to study the different types of reactions

to determine the "strength" of vinegar in vinegar samples In the eighteenth century, the "strength," or the concentration, of vinegar samples was determined by measuring the amount of potassium carbonate that had to be added, a little at a time, before bubbling ceased. This is an early form of titration analysis.

According to the given reaction, how many moles of S8 are required to react with 4.87 moles of F2? S8+24F2⟶8SF6 Your answer should have three significant figures.

.203 mol The coefficients of the balanced chemical reaction give the ratios of the substances in the reaction. S8 has a coefficient of 1, and F2 has a coefficient of 24. Use the stoichiometric factor 1molS824molF2 to calculate moles of S8 from moles of F2. 4.87molF2×1molS824molF2=0.20292molS8 The answer should have three significant figures, so round to 0.203molS8. Notice that coefficients in stoichiometric equations (indicating numbers of moles) are exact, so they do not constrain the number of significant figures.

The end point in a titration of a 58mL sample of aqueous HCl was reached by the addition of 25mL of 0.83MNaOH titrant. The reaction proceeds by the following equation. HCl(aq)+NaOH(aq)→NaCl(aq)+H2O(l) What is the molar concentration ofHCl? Report your answer with two significant figures.

0.36 M

How many moles of C2H6O are required to react with 1.36 mol oxygen gas (O2)? C2H6O+3O2⟶2CO2+3H2O Select the correct answer below: 0.221 moles 0.373 moles 0.414 moles 0.453 moles

0.453 moles Note that C2H6O and O2 react in a 1:3 stoichiometric ratio. Therefore, we can calculate the number of moles of C2H6O as follows. 1.36 mol O2×1mol C2H6O/3mol O2=0.453 moles C2H6O

According to the below equation, how many moles of SO2 are required to generate 1.43×1024 water molecules? 2H2S+SO2→3S+2H2O Use 6.022×1023mol−1 for Avogadro's number. Your answer should have three significant figures.

1.19 mol

How many molecules of CuSO4 are required to react with 2.0 moles Fe? Fe+CuSO4⟶Cu+FeSO4 Use 6.022×1023mol−1 for Avogadro's number. Your answer should have two significant figures.

1.2x10^24 molecules

What mass of H2 is required to produce 16 g H2O in the following reaction? 2H2+O2⟶2H2O Your answer should have two significant figures.

1.8 g

How many moles of NO are required to generate 7.32×1025 NO2 molecules according to the following equation: 2NO+O2→2NO2 Use 6.022×1023mol−1 for Avogadro's number. Your answer should have three significant figures.

122 mols Each mol of NO2 has 6.022 x 1023 molecules So number of mol of NO2 here : 7.32 x 1025 molecules / (6.022 x 1023 molecules/mol) = 122 mol Each mol NO makes one mol of NO2 So here , number of mol of NO required will be : = 122 mols

How many moles of O2 are required to react with 3.0 moles of P4? P4+5O2⟶2P2O5 Your answer should have two significant figures.

15 mol

How many moles of aluminum are necessary to generate 4.88 moles of aluminum oxide, according to the following equation: 4Al+3O2→2Al2O3 Your answer should have three significant figures.

9.76 mol 4.88 moles Al2O3 (4 moles Al / 2 moles Al2O3) = 9.76 moles Al Notice that coefficients in stoichiometric equations (indicating numbers of moles) are exact, so they do not constrain the number of significant figures.

How many molecules of C2H6 are required to react with 5.6 mol O2? 2C2H6+7O2⟶4CO2+6H2O Use 6.022×1023mol−1 for Avogadro's number. Your answer should have two significant figures.

9.6x10^23

If 5.00 g sodium chlorate reacts, how many grams of oxygen (O2) can we expect, according to the following equation: 2NaClO3→2NaCl+3O2 Your answer should have three significant figures.

2.25 grams O2 The mass of the sodium chlorate is known. To determine the mass of oxygen produced by the reaction of 5.00g of NaClO3, multiply the known mass by the molar coefficients that are found in the balanced chemical equation. Finally, convert back to grams of oxygen using the molar mass. 5.00 g NaClO3 x 1 mole NaClO3 / 106.44 g NaClO3 x 3 moles O2 / 2 moles NaClO3 x 31.998 g O2 / 1 mole O2 = 2.254 g of O2 Therefore the mass of oxygen produced rounded to three significant figures is 2.25g. Notice that coefficients in stoichiometric equations (indicating numbers of moles) are exact, so they do not constrain the number of significant figures.

If 75.0 g Fe2O3 and 4.50 g H2 react according to the following equation how many grams of water can we expect: 3H2+Fe2O3→2Fe+3H2O Your answer should have three significant figures. (Round your answer to first decimal place).

25.4 g

If 11.7 g of aluminum reacts with 37.2 g of copper (II) sulfate according to the following reaction, how many grams of aluminum sulfate will be produced? 2Al+3CuSO4→Al2(SO4)3+3Cu Your answer should have three significant figures. (Round your answer to the first decimal place.)

26.6 grams

How many molecules of HCl are required to react with 2.50 moles Zn? Zn+2HCl⟶ZnCl2+H2 Use 6.022×1023mol−1 for Avogadro's number. Your answer should have three significant figures. When reporting your answer in scientific notation format, use the multiplication symbol, ×, not the letter x.

3.01x10^24 2 HCl1 Zn×2.50 moles×(6.022×1023)=3.01×1024 molecules HCl Notice that coefficients in stoichiometric equations (indicating numbers of moles) are exact, so they do not constrain the number of significant figures.

If 9.3gNO2 are produced, how many grams of oxygen (O2) must have reacted according to the following equation: 2NO+O2→2NO2 Your answer should have two significant figures.

3.2 g First, calculate the number of moles of NO2 that are produced: 9.3gNO2×1molNO2/46.005gNO2=0.20215molNO2 Next, use a ratio to solve for the number of moles of O2 that should be formed: 1molO2/2molNO2=xmolO2/0.20215molNO2 x=0.10108molO2 Finally, convert the moles of O2 to grams of O2: 0.10108molO2×31.998gO2/1molO2=3.2342gO2 The answer should have two significant figures, so round to 3.2gO2. Notice that coefficients in stoichiometric equations (indicating numbers of moles) are exact, so they do not constrain the number of significant figures.

If 4.0 mol aluminum and 7.0 mol hydrogen bromide react according to the following equation, how many moles of hydrogen are formed and what is the limiting reactant? 2Al+6HBr→2AlBr3+3H2 6.0 molH2, HBr 3.5 molH2, HBr 6.0 molH2, Al 3.5 molH2, Al

3.5 mol H2, HBr

How many grams of P4 are required to produce 10.2 g P2O5 (assuming an excess of oxygen)? P4+5O2→2P2O5 Your answer should have three significant figures.

4.45 g

What is the percent yield of the given reaction if 40. g magnesium reacts with excess nitric acid to produce 1.7 g hydrogen gas? Mg+2HNO3⟶Mg(NO3)2+H2 Your answer should have two significant figures.

51%

If 45.0 g H2S and 104.0 g SO2 react, how many grams of sulfur will form according to the following equation? 2H2S+SO2→3S+2H2O Your answer should have three significant figures. (Round your answer to first decimal place).

63.4 grams

What is the percent yield of water if we start with 5 g C3H8 and produce 6.13 g H2O? C3H8 + 5O2 -> 3CO2 + 4H2O

75.03%

What is the percent yield of sodium hydroxide in the given reaction? The reaction was performed using 45 g NaHCO3 and 18 g NaOH were produced. NaHCO3⟶NaOH+CO2 Your answer should have two significant figures.

84%