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Honors Chemistry > Module 05: Stoichiometry > Flashcards

Module 05: Stoichiometry Flashcards

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1
Q

01.05 The Mole Concept

What is true about 1.0 mol Ca and 1.0 mol Mg? (3 points)

  1. They are equal in mass.
  2. They contain the same number of atoms.
  3. They have the same atomic mass.
  4. Their molar masses are equal.
A

2. They contain the same number of atoms.

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2
Q

01.05 The Mole Concept

What is the molar mass of silver (Ag)? (3 points)

  1. 47.0 g/mol
  2. 60.02 g/mol
  3. 107.87 g/mol
  4. 196.97 g/mol
A

3. 107.87 g/mol

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3
Q

01.05 The Mole Concept

How many moles of copper (Cu) are in 65.8 g Cu? (3 points)

  1. 1.04 mol Cu
  2. 10.9 mol Cu
  3. 41.7 mol Cu
  4. 63.5 mol Cu
A

1. 1.04 mol Cu

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4
Q

01.05 The Mole Concept

How many moles are in a sample of 1.52 x 1024 atoms of mercury (Hg)? (3 points)

  1. 1.75 mol Hg
  2. 2.52 mol Hg
  3. 91.5 mol Hg
  4. 50.4 mol Hg
A

2. 2.52 mol Hg

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5
Q

01.05 The Mole Concept

Avogadro’s number is used to determine the number of subatomic particles in an atom. (2 points)

True

False

A

False

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6
Q

01.05 The Mole Concept

Which of the following processes will determine the number of moles in a sample? (3 points)

  1. Dividing the mass of the sample by Avogadro’s number
  2. Multiplying the mass of the sample by Avogadro’s number
  3. Dividing the number of molecules in the sample by Avogadro’s number
  4. Multiplying the number of molecules in the sample by Avogadro’s number
A

3. Dividing the number of molecules in the sample by Avogadro’s number

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7
Q

01.05 The Mole Concept

How many moles of silver are equivalent to 2.408 × 1024 atoms? (3 points)

  1. 4
  2. 2.5
  3. 0.25
  4. 0.4
A

1. 4

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8
Q

01.05 The Mole Concept

What is the number of atoms in a mole of any element? (3 points)

  1. Avogadro’s number
  2. Graham’s number
  3. Its atomic number
  4. Its mass number
A

1. Avogadro’s number

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9
Q

01.05 The Mole Concept

What is the mass of 6.12 moles of arsenic (As)? (3 points)

  1. 12.2 g As
  2. 73.7 g As
  3. 276 g As
  4. 459 g As
A

4. 459 g As

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10
Q

01.05 The Mole Concept

How many atoms of iron (Fe) are in a sample of 7.38 mol Fe? (3 points)

  1. 1.23 x 1023 atoms Fe
  2. 5.58 x 1023 atoms Fe
  3. 3.37 x 1024 atoms Fe
  4. 4.44 x 1024 atoms Fe
A

4. 4.44 x 1024 atoms Fe

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11
Q

01.05 The Mole Concept

Which of the following processes will determine the number of atoms in a sample? (3 points)

  1. Dividing the mass of the sample by its molar mass
  2. Multiplying the mass of the sample by its molar mass
  3. Dividing the number of moles of the sample by Avogadro’s number
  4. Multiplying the number of moles of the sample by Avogadro’s number
A

4. Multiplying the number of moles of the sample by Avogadro’s number

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12
Q

01.05 The Mole Concept

How many moles of gold are equivalent to 1.204 × 1024 atoms? (3 points)

  1. 0.2
  2. 0.5
  3. 2
  4. 5
A

3. 2

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13
Q

01.05 The Mole Concept

What is the empirical formula of C6H12O6? (4 points)

C2H4O2

CH2O

CH2O2

C2H4O

A
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14
Q

01.05 The Mole Concept

What is a mole? What is the purpose?

A

Moles (mol): represent number & counting units

  • number of atoms in carbon 12 → avogadro’s number

Molar mass: total mass in grams on one mole in a substance

Amu on periodic table = 1 mole

Why use the mole?

  1. many chemical properties depend on particle number (not mass)
  2. Atoms too small count individually without special equipment
  3. relationship between mass and number = determine numbe particles
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15
Q

01.05 The Mole Concept

What is Avogadro’s Number?

A

Number particles in mole experimentally determined variety of ways

Use: mass spectrometer (count atoms precisely)

Avogadro’s number: 6.02214 × 1023

1 mole = 6.022 × 1023 particles

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16
Q

01.05 The Mole Concept

What is the relationship between moles and molar mass?

A

Mass of 1 Mole = Average Atomic Mass = Molar Mass

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17
Q

01.05 The Mole Concept

How to convert from number of moles to number of atoms:

A

Given number of atoms x (6.022 x 1023 atoms) / 1 mole = number of atoms

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18
Q

01.05 The Mole Concept

How to convert from the number of atoms to moles?

A

Given number of atoms x (1 mole / 6.022 x 1023 atoms) = number of moles

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19
Q

01.05 The Mole Concept

How to convert from grams to atoms:

A
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20
Q

How to convert from atoms to mass (g)?

A
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21
Q

05.02 Molar Mass of Compounds

Define mass value on the periodic table:

A

mass (grams) of one mole (6.022 * 1023) of an element

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22
Q

05.02 Molar Mass of Compounds

How to calculate thee molar mass of a compound:

A

Subscrips: indicate amount of moles in compound

Step 01: Find molar mass on table

Step 02: multiply mass of each element by its subscript

Step 03: add up results

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23
Q

05.02 Molar Mass of Compounds

What is the molar mass of Na2CO3? (3 points)

  1. 60.0 g/mol
  2. 106.0 g/mol
  3. 118.0 g/mol
  4. 141.0 g/mol
A

2. 106.0 g/mol

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24
Q

05.02 Molar Mass of Compounds

How many moles of each element are in one mole of Be(OH)2? (3 points)

  1. 1 mole of beryllium, 1 mole of oxygen, 2 moles of hydrogen
  2. 1 mole of beryllium, 2 moles of oxygen, 2 moles of hydrogen
  3. 2 moles of beryllium, 2 moles of oxygen, 2 moles of hydrogen
  4. 2 moles of beryllium, 1 mole of oxygen, 1 moles of hydrogen
A

2. 1 mole of beryllium, 2 moles of oxygen, 2 moles of hydrogen

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25
Q

05.02 Molar Mass of Compounds

How many moles are in 123.0 grams of KClO4? (3 points)

  1. 0.2354 mol KClO4
  2. 0.6445 mol KClO4
  3. 0.7124 mol KClO4
  4. 0.8878 mol KClO4
A

4. 0.8878 mol KClO4

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26
Q

05.02 Molar Mass of Compounds

What is the mass of 4.32 mol GaI3? (3 points)

  1. 455 g
  2. 1,230 g
  3. 1,720 g
  4. 1,950 g
A

4. 1,950 g

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27
Q

05.02 Molar Mass of Compounds

What is the molar mass of H2SO4?

(Molar mass of H = 1.0079 g/mol; S = 32.065 g/mol; O = 15.999 g/mol) (3 points)

  1. 98.08 g/mol
  2. 88.22 g/mol
  3. 86.79 g/mol
  4. 79.02 g/mol
A

1. 98.08 g/mol

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28
Q

05.02 Molar Mass of Compounds

Calculate the mass of 3.4 moles of nitric acid (HNO3). Explain the process or show your work by including all values used to determine the answer. (5 points)

A

Firstly, determine the molar mass of nitric acid. There is 1 atom of Hydrogen, 1 atom of Nitrogen, and three atoms of Oxygen. Determine their individual masses and add the multiple of each other to find the total molar mass of the compound:

1H+1N+3O=1(1.0079)+1(14.0067)+3(15.9994)=63.0128

Therefore, the molar mass is 63.0128 g/mol HNO3.

Next, in order to determine the mass of 3.4 of HNO3, an appropriate conversion factor needs to be found. Since the conversion is from moles to mass, the following formula is needed: Given moles of a sample * (molar mass of compound) ÷ (1 mole) = mass of a sample. Hence, the conversion is 3.4 mol * (63.0128 g/mol)/1 mol = x.

3.4⋅63.01281=214.24g. Therefore, the mass of 3.4 moles of nitric acid is 214.24 grams.

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29
Q

05.03 The Empirical Formula

What is Percent Composition?

A
  • Ratios
  • represented empirical formula & molar mass

Step 01: Find the number of atoms in the empirical formula

Step 02: Find the molar mass

  1. find on periodic table
  2. multiply value in empirical formula

Step 03: Total individual molar masses to find total

Step 04: Calculate Percentage Composition by divide the molar mass of each element by molar mass of total molar mass

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30
Q

05.03 The Empirical Formula

Determine Empirical Formula:

A

Step 01: Check composition of compound (should be in grams)

  • if the sample is in percentage convert it assuming it is a 100-gram sample

Step 02: Convert amount element from grams to moles

  • conversion factor of (1 mole) ÷ (molar mass of substance)

Step 03: Divide each mole value by lowest mole value of all elements = whole-number mole ratio

  • mole values are mole ratio
  • empirical formula requires lowest whole-number ratio

Step 04: If the values are not a whole number, multiply all mole values by a number make them a whole number

Step 05: Use whole-numbers as subscripts when writing the empirical formula

31
Q

05.03 The Empirical Formula

How to convert from the Empirical formula to the Molecular formula?

A

Step 01: Calculate molar mass of empirical formula in same way you would calculate molar mass of a compound

Step 02: Divide (entire compound) molecular mass by mass empirical formula → ratio between molecular formula and empirical formula (whole number)

Step 03: Multiply subscripts in empirical formula by ratio to get molecular formula

32
Q

05.03 The Empirical Formula

What is the empirical formula of C6H12O6? (4 points)

  1. C2H4O2
  2. CH2O
  3. CH2O2
  4. C2H4O
A

2. CH2O

33
Q

05.03 The Empirical Formula

Which pair shares the same empirical formula? (4 points)

  1. C2H4 and C6H6
  2. C6H6 and C3H3
  3. CH2 and C6H6
  4. CH and C2H4
A

2. C6H6 and C3H3

34
Q

05.03 The Empirical Formula

What is the percent composition of NaHCO3? (4 points)

  1. 23.20% Na, 4.26% H, 18.41% C, and 54.13% O
  2. 24.21% Na, 4.35% H, 12.26% C, and 59.18% O
  3. 27.36% Na, 1.20% H, 14.30% C, and 57.14% O
  4. 30.44% Na, 2.12% H, 10.25% C, and 60.19% O
A

3. 27.36% Na, 1.20% H, 14.30% C, and 57.14% O

35
Q

05.03 The Empirical Formula

A compound is 40% carbon, 6.7% hydrogen, and 53.3% oxygen. What is the empirical formula? (4 points)

  1. CH2O2
  2. CH2O
  3. C2H4O
  4. C2H4O2
A

2. CH2O

36
Q

05.03 The Empirical Formula

The empirical formula of a chemical substance is CH. The molar mass of a molecule of the substance is 78.11 g/mol. What is the molecular formula of the chemical substance? (4 points)

  1. C2H2
  2. C2H4
  3. C3H4
  4. C6H6
A

4. C6H6

37
Q

05.04 Stoichiometry

Define stoichiometry:

A

dimensional analysis (math conversions) starts with one substance and ends with different substance

38
Q

05.04 Stoichiometry

What is a mole ratio?

A

a conversion factor used in stoichiometry that describes the ratio between compounds or elements in a chemical reaction

39
Q

05.04 Stoichiometry

How do you determine the mass value of a substance?

A

Step 01: Write a balanced Equation

Step 02: Begin stoichiometry using molar mass of starting substance

Step 03: Create mole ratio from coefficients of two compounds of interest

Step 04: Include mole ratio in stoichiometry conversion

Step 05: Include conversion factor for the molar mass of ending substance

Step 06: Solve through dimensional analysis

40
Q

05.04 Stoichiometry

What is a valid mole ratio from the balanced equation 2C3H6 + 9O2 → 6CO2 + 6H2O? (4 points)

A

6 mole H20 / 9 mole O2

41
Q

05.04 Stoichiometry

How many moles of calcium chloride (CaCl2) are needed to react completely with 6.2 moles of silver nitrate (AgNO3)?

2AgNO3 + CaCl2 → 2AgCl + Ca(NO3)2 (4 points)

  1. 2.2 mol CaCl2
  2. 3.1 mol CaCl2
  3. 6.2 mol CaCl2
  4. 12.4 mol CaCl2
A

2. 3.1 mol CaCl2

42
Q

05.04 Stoichiometry

What mass of Fe can be produced by the reaction of 75.0 g CO with excess Fe2O3 according to the equation: Fe2O3(s) + CO(g) → Fe(s) + CO2(g)? (4 points)

  1. 49.8 g Fe
  2. 99.7 g Fe
  3. 224 g Fe
  4. 299 g Fe
A

2. 99.7 g Fe

43
Q

05.04 Stoichiometry

How many moles of sulfuric acid (H2SO4) are needed to react completely with 6.8 moles of lithium hydroxide (LiOH)?

2LiOH + H2SO4 → Li2SO4 + 2H2O (4 points)

  1. 3.4 mol H2SO4
  2. 6.8 mol H2SO4
  3. 10.2 mol H2SO4
  4. 13.6 mol H2SO4
A

1. 3.4 mol H2SO4

44
Q

05.04 Stoichiometry

What mass of Fe can be produced by the reaction of 75.0 g CO with excess Fe2O3 according to the equation: Fe2O3(s) + CO(g) → Fe(s) + CO2(g)? (4 points)

  1. 49.8 g Fe
  2. 99.7 g Fe
  3. 224 g Fe
  4. 299 g Fe
A

2. 99.7 g Fe

45
Q

05.04 Stoichiometry

In an experiment, potassium chlorate decomposed according to the following chemical equation.

KClO3 → KCl + O2

(Molar mass of KClO3 = 122.5 g/mol; KCl = 74.55 g/mol; O2 = 31.998 g/mol)

If the mass of potassium chlorate was 240 grams, which of the following calculations can be used to determine the mass of oxygen gas formed? (4 points)

  1. (240 × 2 × 31.998) ÷ (122.5 × 3) grams
  2. (240 × 3 × 31.998) ÷ (122.5 × 2) grams
  3. (240 × 2 × 122.5) ÷ (31.998 × 3) grams
  4. (240 × 3 × 122.5) ÷ (31.998 × 2) grams
A

2. (240 × 3 × 31.998) ÷ (122.5 × 2) grams

46
Q

05.05 Limiting Reactant

Define limiting and excess reactant:

A

Limiting Reactant: Runs out first

Excess Reactant: not used up completely

47
Q

05.05 Limiting Reactant

Define Theoretical Yield:

A

maximum amount product expect from reaction (one run out before the other)

48
Q

05.05 Limiting Reactant

What are the steps to determine the limiting reactants and moles?

A

Step 01: Determine limiting reactant by identifying the given about of reactants and what product is being solved for

Step 02: Write balanced equations and use it to create a mole ratio for the given reactant and product

Step 03: Set up and solve a stoichiometry calculation for each reactant using the mole ratios

Step 04: The Lower amous is the theoretical yield

49
Q

05.05 Limiting Reactant

How to determine the mass of a theoretical yield?

A

Step 01: Determine if this is a limiting reactant problem by recognizing there are given starting amounts for both reactants. Balance the chemical reaction.

Step 02: Set up the stoichiometry calculation for each reactant using the periodic table to determine individual moral mass

Step 03: Use balanced equation to create mole ratio for the given reactants and products

Step 04: Include mole ratio for each stoichiometry calculation

Step 05: Include conversion factor for molar mass of ending substance for each calculation (solve through dimensional analysis)

Step 06: Lower amount is theoretical yield

50
Q

05.05 Limiting Reactant

Consider the reaction 2CuCl2 + 4KI → 2CuI + 4KCl + I2. If 4 moles of CuCl2 react with 4 moles of KI, what is the limiting reactant? (3 points)

  1. CuCl2
  2. KI
  3. CuI
  4. I2
A
  1. Kl
51
Q

05.05 Limiting Reactant

If 18.5 grams of CuCl2 react with 22.8 grams of NaNO3, what mass of NaCl can be formed?

CuCl2 + NaNO3 → Cu(NO3)2 + NaCl (3 points)

  1. 12.4 g NaCl
  2. 15.7 g NaCl
  3. 16.2 g NaCl
  4. 28.4 g NaCl
A

2. 15.7 g NaCl

52
Q

05.05 Limiting Reactant

Read the chemical equation.

Fe2O3 + CO → Fe + CO2

If 3 moles of Fe2O3 react with 1.5 moles of CO, how many moles of each product are formed? (3 points)

  1. 1 mole of Fe and 1.5 moles of CO2
  2. 0.5 mole of Fe and 1 mole of CO2
  3. 6 moles of Fe and 9 moles of CO2
  4. 3 moles of Fe and 2 moles of CO2
A

1, 1 mole of Fe and 1.5 moles of CO2

53
Q

05.06 Percent Yield

Define percentage yield:

A

Percent Yield: Actual Yield / Theoretical Yield * 100

Percent Yield: ration acual yield to theoretical yield multiplied by 100

Theoretical Yield: maximum amount of product able to be produced from a given amount of reactant(s) (calculated)

Actual Yield: amount of product that is actually formed (measured)

reasons:

  1. conditions not allowed reaction run to completion
  2. purification of product results in loss of some of the product

The actual yield cannot exceed the theoretical yield. In practice, sometimes it appears that way, but that’s because an error occurred in the lab. This will be important to remember as you complete percent yield calculations.

54
Q

05.09 Honors Stoichiometry Exam

05.09 Honors Stoichiometry Exam

A
55
Q

05.09 Honors Stoichiometry Exam

How many atoms of Mg are present in 97.22 grams of Mg? (4 points)

  1. 6.022 × 1023
  2. 2.408 × 1024
  3. 4.818 × 1024
  4. 5.855 × 1025
A

2. 2.408 × 1024

56
Q

05.09 Honors Stoichiometry Exam

One mole of zinc has a mass of 65.4 grams. Approximately how many atoms of zinc are present in one mole of zinc? (4 points)

  1. 32 × 1023 atoms
  2. 6 × 1023 atoms
  3. 66 atoms
  4. 65 atoms
A

2. 6 × 1023 atoms

57
Q

05.09 Honors Stoichiometry Exam

Which of the following best defines the molar mass of a substance? (4 points)

  1. Mass, in grams, of each particle of the substance
  2. Total mass, in grams, of 100 particles of the substance
  3. Mass, in grams, of the nucleus of the substance’s atoms
  4. Total mass, in grams, of all the particles in one mole of the substance
A

4. Total mass, in grams, of all the particles in one mole of the substance

58
Q

05.09 Honors Stoichiometry Exam

Which formula can be used to calculate the molar mass of ammonia (NH3)? (4 points)

  1. molar mass of N + molar mass of H
  2. 3 × molar mass of N + molar mass of H
  3. molar mass of N + 3 × molar mass of H
  4. 3 × molar mass of N + 3 × molar mass of H
A

3. molar mass of N + 3 × molar mass of H

59
Q

05.09 Honors Stoichiometry Exam

How many moles of MgCO3 are present in 252.939 grams of MgCO3? (4 points)

  1. 2
  2. 3
  3. 5
  4. 6
A

2. 3

60
Q

05.09 Honors Stoichiometry Exam

Which pair of compounds has the same empirical formula? (4 points)

  1. C2H6 and CH
  2. CH3 and C2H6
  3. C3H8 and C3H
  4. C2H2 and C2H
A

2. CH3 and C2H6

61
Q

05.09 Honors Stoichiometry Exam

What is the percentage composition of each element in hydrogen peroxide, H2O2? (4 points)

  1. 7.01% H and 92.99% O
  2. 7.22% H and 92.78% O
  3. 6.32% H and 93.68% O
  4. 5.88% H and 94.12% O
A

4. 5.88% H and 94.12% O

62
Q

05.09 Honors Stoichiometry Exam

Determine the empirical formula of a compound containing 47.37 grams of carbon, 10.59 grams of hydrogen, and 42.04 grams of oxygen.

In an experiment, the molar mass of the compound was determined to be 228.276 g/mol. What is the molecular formula of the compound?

For both questions, show your work or explain how you determined the formulas by giving specific values used in calculations. (8 points)

A

Empirical Formula:

Convert to moles:

  1. 37 grams of carbon = 3.944 moles of carbon
  2. 58 grams of hydrogen = 10.497 moles of hydrogen
  3. 04 grams of oxygen = 2.628 moles of oxygen

Divide each element by the lowest value:

  1. 944 mol C ÷ 2.628 = 1.500 mol C
  2. 497 mol H ÷ 2.628 = 3.994 = 4 mol H
  3. 628 mol O ÷ 2.628 = 1 mole O
  4. 5 * 2 = 3 mol C

4 * 2 = 8 mol H

1 * 2 = 2 mol O

Therefore, the empirical formula is C3H8O2.

Molecular Formula:

Molar mass of molecule: 228.276 g/mol

Molar mass empirical formula: 3(12.0107) + 8(1.0079) + 2(15.9994) = 76.0941 g/mol

=228.27676.0941

=2.999≈3

=3⋅C3H8O2

=C9H24O6

63
Q

05.09 Honors Stoichiometry Exam

Which of the following is necessary to do a complete stoichiometric calculation? (4 points)

  1. Write the mole ratio.
  2. Add the nuclear masses of the products.
  3. Divide the nuclear masses of the reactants.
  4. Write the number of atoms in one mole of the product.
A

1. Write the mole ratio

64
Q

05.09 Honors Stoichiometry Exam

The following reaction shows sodium hydroxide reacting with sulfuric acid.

4NaOH + 2H2SO4 → 2Na2SO4 + 4H2O

How many grams of Na2SO4 are produced from 10.0 grams of NaOH?

(Molar mass of Na = 22.989 g/mol, O = 15.999 g/mol, H = 1.008 g/mol, S = 32.065 g/mol) (4 points)

  1. 17.8 grams
  2. 19.2 grams
  3. 35.5 grams
  4. 38.5 grams
A

1.

  1. 17.8 grams
65
Q

05.09 Honors Stoichiometry Exam

Read the given chemical reaction.

C2H6 + O2 → CO2 + H2O

How many moles of CO2 are produced during the complete combustion of 3.6 moles of C2H6? (4 points)

  1. 1.8 moles
  2. 4.4 moles
  3. 7.2 moles
  4. 9.2 moles
A

3. 7.2 moles

66
Q

05.09 Honors Stoichiometry Exam

Which of the following statements best describes a limiting reactant? (4 points)

  1. The reactant that is used up the least
  2. The reactant that is used up the most
  3. The reactant that is used up before the others
  4. The reactant that is leftover after the reaction
A

3. The reactant that is used up before the others

67
Q

05.09 Honors Stoichiometry Exam

How many moles of water are produced when 3.0 moles of hydrogen gas react with 1.8 moles of oxygen gas?

Balanced equation: 2H2 + O2 → 2H2O (4 points)

  1. 3.0 moles of water
  2. 3.6 moles of water
  3. 5.3 moles of water
  4. 7.0 moles of water
A

1. 3.0 moles of water

68
Q

05.09 Honors Stoichiometry Exam

A chemist wants to extract copper metal from copper chloride solution. The chemist places 0.25 grams of aluminum foil in a solution of 0.40 grams of copper (II) chloride. A single replacement reaction takes place. What are the likely observations when the reaction stops?

Unbalanced equation: CuCl2 + Al → AlCl3 + Cu (4 points)

  1. About 0.90 grams of copper is formed, and some aluminum is left in the reaction mixture
  2. About 0.20 grams of copper is formed, and some aluminum is left in the reaction mixture.
  3. About 0.90 grams of copper is formed, and some copper chloride is left in the reaction mixture.
  4. About 0.20 grams of copper is formed, and some copper chloride is left in the reaction mixture.
A

2. About 0.20 grams of copper is formed, and some aluminum is left in the reaction mixture

69
Q

05.09 Honors Stoichiometry Exam

Which of the following statements best defines the theoretical yield of a reaction? (4 points)

  1. The ratio of measured yield over actual yield
  2. The amount of product measured after a reaction
  3. The ratio of measured yield over stoichiometric yield
  4. The maximum amount of product that can be obtained
A

4. The maximum amount of product that can be obtained

70
Q

05.09 Honors Stoichiometry Exam

The actual yield of a product in a reaction was measured as 4.20 g. If the theoretical yield of the product for the reaction is 4.88 g, what is the percentage yield of the product? (4 points)

  1. 6%
  2. 2%
  3. 1%
  4. 0%
A
  1. 86.1 %
71
Q

05.09 Honors Stoichiometry Exam

A chemist reacted 57.50 grams of sodium metal with an excess amount of chlorine gas. The chemical reaction that occurred is shown.

Na + Cl2 → NaCl

If the percentage yield of the reaction is 86%, what is the actual yield? Show your work, including the use of stoichiometric calculations and conversion factors. (8 points)

A

Theoretical Yield:

Since the chlorine gas in excess, sodium is the limiting reactant in the reaction. The balanced equation for the above reaction is 2Na+Cl2→2NaCl. The theoretical yield will be as follows:

=57.51⋅145.9794⋅22⋅116.88541

=146.172 grams theoretical yield

Actual Yield:

Actual Yield = (Percent Yield * Theoretical Yield) ÷ 100

=12570.792100

=125.708100

=125.708 grams actual yield

72
Q

05.09 Honors Stoichiometry Exam

The following reaction shows the products when sulfuric acid and aluminum hydroxide react.

2Al(OH)3 + 3H2SO4 → Al2(SO4)3 + 6H2O

The table shows the calculated amounts of reactants and products when the reaction was conducted in a laboratory.

What is the approximate amount of the leftover reactant? (4 points)

  1. 8.2 g of sulfuric acid
  2. 9.8 g of sulfuric acid
  3. 11.43 g of aluminum hydroxide
  4. 13.76 g of aluminum hydroxide
A

3. 11.43 g of aluminum hydroxide

73
Q

05.09 Honors Stoichiometry Exam

In the following reaction, oxygen is the excess reactant.

SiCl4 + O2 → SiO2 + Cl2

The table shows an experimental record for the above reaction.

Calculate the percentage yield for SiO2 for Trial 1. Also, determine the leftover reactant for the trial. Show your work.

A
74
Q

In the following reaction, oxygen is the excess reactant.

SiCl4 + O2 → SiO2 + Cl2

The table shows an experimental record for the above reaction.

Based on the percentage yield in Trial 2, explain what ratio of reactants is more efficient for the given reaction.

A

Honors Chemistry (8 decks)

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