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Chapter 4 SABIS Grade 10 Problems

Problems on Chapter 4

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📝 Lesson 24 📝 Summary

Basic Ideas

Problems


1. Stoichiometry and Mole-to-Mole Ratio:


- Find the number of moles of products formed from a given number of moles of reactants.

- Find the number of moles of reactant needed to form a given number of moles of product.



Easy Questions:

  1. If 2 moles of hydrogen (H2) react with 1 mole of oxygen (O2) to form water (H2O), how many moles of water will be produced?

  2. In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), if 1 mole of nitrogen reacts, how many moles of ammonia are produced?

  3. If 1 mole of carbon dioxide (CO2) is decomposed into its elements, how many moles of oxygen (O2) are produced?

Medium Difficulty Questions:

  1. In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), if 4 moles of iron(III) oxide are produced, how many moles of iron were needed?

  2. In the synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2), if you want to produce 10 moles of ammonia, how many moles of nitrogen will you need?

  3. In the decomposition of water (H2O) into hydrogen (H2) and oxygen (O2), if you start with 18 moles of water, how many moles of oxygen will be produced?


Answers


Easy Questions:


If 2 moles of hydrogen (H2) react with 1 mole of oxygen (O2) to form water (H2O), how many moles of water will be produced?Answer: 2 moles of water will be produced. (Based on the balanced equation: 2H2 + O2 -> 2H2O)


In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), if 1 mole of nitrogen reacts, how many moles of ammonia are produced?Answer: 2 moles of ammonia are produced. (Based on the balanced equation: N2 + 3H2 -> 2NH3)


If 1 mole of carbon dioxide (CO2) is decomposed into its elements, how many moles of oxygen (O2) are produced?Answer: 1 mole of oxygen is produced. (Based on the balanced equation: CO2 -> C + O2)


Medium Difficulty Questions:


In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), if 4 moles of iron(III) oxide are produced, how many moles of iron were needed?Answer: 8 moles of iron were needed. (Based on the balanced equation: 4Fe + 3O2 -> 2Fe2O3)


In the synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2), if you want to produce 10 moles of ammonia, how many moles of nitrogen will you need?Answer: 5 moles of nitrogen are needed. (Based on the balanced equation: N2 + 3H2 -> 2NH3)


In the decomposition of water (H2O) into hydrogen (H2) and oxygen (O2), if you start with 18 moles of water, how many moles of oxygen will be produced?Answer: 9 moles of oxygen are produced. (Based on the balanced equation: 2H2O -> 2H2 + O2)



2. Mass Relations and Mass-to-Mass Ratio:


- Write the mass ratio of a given reaction.


Easy Questions:

  1. In the reaction of hydrogen (H2) with oxygen (O2) to form water (H2O), what is the mass ratio of hydrogen to oxygen?

    • Answer: The mass ratio of hydrogen to oxygen is 2g:32g.

  2. In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), what is the mass ratio of nitrogen to hydrogen?

    • Answer: The mass ratio of nitrogen to hydrogen is 28g:6g.

  3. In the reaction of carbon (C) with oxygen (O2) to form carbon dioxide (CO2), what is the mass ratio of carbon to oxygen?

    • Answer: The mass ratio of carbon to oxygen is 12g:32g.

Medium Difficulty Questions:

  1. In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), what is the mass ratio of iron to oxygen?

    • Answer: The mass ratio of iron to oxygen is 112g:96g.

  2. In the synthesis of ammonia (NH3) from nitrogen (N2) and hydrogen (H2), what is the mass ratio of nitrogen to hydrogen?

    • Answer: The mass ratio of nitrogen to hydrogen is 28g:6g.

  3. In the decomposition of water (H2O) into hydrogen (H2) and oxygen (O2), what is the mass ratio of hydrogen to oxygen?

    • Answer: The mass ratio of hydrogen to oxygen is 2g:32g.



- Find the mass of the product formed from a given mass of reactant.



Easy Problems:

  1. If 4 grams of hydrogen (H2) react with sufficient oxygen (O2) to form water (H2O), what is the mass of water formed?

    • Answer: The molar mass of hydrogen (H2) is 2g/mol and that of water (H2O) is 18g/mol. Therefore, the mass of water formed is (4g H2) * (18g H2O / 2g H2) = 36g of H2O.

  2. If 28 grams of nitrogen (N2) react with sufficient hydrogen (H2) to form ammonia (NH3), what is the mass of ammonia formed?

    • Answer: The molar mass of nitrogen (N2) is 28g/mol and that of ammonia (NH3) is 17g/mol. Therefore, the mass of ammonia formed is (28g N2) * (2 * 17g NH3 / 28g N2) = 34g of NH3.

  3. If 12 grams of carbon (C) react with sufficient oxygen (O2) to form carbon dioxide (CO2), what is the mass of carbon dioxide formed?

    • Answer: The molar mass of carbon (C) is 12g/mol and that of carbon dioxide (CO2) is 44g/mol. Therefore, the mass of carbon dioxide formed is (12g C) * (44g CO2 / 12g C) = 44g of CO2.

Difficult Problems:

  1. If 64 grams of sulfur (S8) react with sufficient oxygen (O2) to form sulfur dioxide (SO2), what is the mass of sulfur dioxide formed?

    • Answer: The molar mass of sulfur (S8) is 256g/mol and that of sulfur dioxide (SO2) is 64g/mol. Therefore, the mass of sulfur dioxide formed is (64g S8) * (8 * 64g SO2 / 256g S8) = 128g of SO2.

  2. If 56 grams of iron (Fe) react with sufficient oxygen (O2) to form iron(III) oxide (Fe2O3), what is the mass of iron(III) oxide formed?

    • Answer: The molar mass of iron (Fe) is 56g/mol and that of iron(III) oxide (Fe2O3) is 160g/mol. Therefore, the mass of iron(III) oxide formed is (56g Fe) * (160g Fe2O3 / 112g Fe) = 80g of Fe2O3.

  3. If 27 grams of aluminum (Al) react with sufficient oxygen (O2) to form aluminum oxide (Al2O3), what is the mass of aluminum oxide formed?

    • Answer: The molar mass of aluminum (Al) is 27g/mol and that of aluminum oxide (Al2O3) is 102g/mol. Therefore, the mass of aluminum oxide formed is (27g Al) * (102g Al2O3 / 54g Al) = 51g of Al2O3.



- Find the mass of a given number of moles of a substance.


Easy Problems:

  1. What is the mass of 2 moles of hydrogen (H2)?

    • Answer: The molar mass of hydrogen (H2) is 2g/mol. Therefore, the mass of 2 moles of hydrogen is (2 moles) * (2g/mol) = 4g.

  2. What is the mass of 1 mole of nitrogen (N2)?

    • Answer: The molar mass of nitrogen (N2) is 28g/mol. Therefore, the mass of 1 mole of nitrogen is (1 mole) * (28g/mol) = 28g.

  3. What is the mass of 3 moles of carbon (C)?

    • Answer: The molar mass of carbon (C) is 12g/mol. Therefore, the mass of 3 moles of carbon is (3 moles) * (12g/mol) = 36g.

Difficult Problems:

  1. What is the mass of 0.5 moles of sulfur (S8)?

    • Answer: The molar mass of sulfur (S8) is 256g/mol. Therefore, the mass of 0.5 moles of sulfur is (0.5 moles) * (256g/mol) = 128g.

  2. What is the mass of 2.5 moles of iron (Fe)?

    • Answer: The molar mass of iron (Fe) is 56g/mol. Therefore, the mass of 2.5 moles of iron is (2.5 moles) * (56g/mol) = 140g.

  3. What is the mass of 1.5 moles of aluminum (Al)?

    • Answer: The molar mass of aluminum (Al) is 27g/mol. Therefore, the mass of 1.5 moles of aluminum is (1.5 moles) * (27g/mol) = 40.5g.




3. Volume Relations and Volume-to-Mole Ratio:


- Give the reacting ratios in moles, mass, and volume.

Easy Problems:


In the reaction of hydrogen (H2) with oxygen (O2) to form water (H2O), what are the reacting ratios in moles, mass, and volume?


Answer: The reacting ratios are 2:1 in moles (2 moles of H2 react with 1 mole of O2), 2g:32g in mass, and 44.8L:22.4L in volume.

In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), what are the reacting ratios in moles, mass, and volume?


Answer: The reacting ratios are 1:3 in moles (1 mole of N2 reacts with 3 moles of H2), 28g:6g in mass, and 22.4L:67.2L in volume.

In the reaction of carbon (C) with oxygen (O2) to form carbon dioxide (CO2), what are the reacting ratios in moles, mass, and volume?


Answer: The reacting ratios are 1:1 in moles (1 mole of C reacts with 1 mole of O2), 12g:32g in mass, and 22.4L:22.4L in volume.

Difficult Problems:


In the reaction of sulfur (S8) with oxygen (O2) to form sulfur dioxide (SO2), what are the reacting ratios in moles, mass, and volume?


Answer: The reacting ratios are 1:8 in moles (1 mole of S8 reacts with 8 moles of O2), 256g:256g in mass, and 22.4L:179.2L in volume.

In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), what are the reacting ratios in moles, mass, and volume?


Answer: The reacting ratios are 4:3 in moles (4 moles of Fe react with 3 moles of O2), 224g:96g in mass. Volume ratio is not applicable as iron is a solid.

In the reaction of aluminum (Al) with oxygen (O2) to form aluminum oxide (Al2O3), what are the reacting ratios in moles, mass, and volume?


Answer: The reacting ratios are 4:3 in moles (4 moles of Al react with 3 moles of O2), 108g:96g in mass. Volume ratio is not applicable as aluminum is a solid.





- Find the volume of one reactant needed to react with a given number of moles of another reactant.



Easy Problems:

  1. In the reaction of hydrogen (H2) with oxygen (O2) to form water (H2O), what volume of hydrogen is needed to react with 1 mole of oxygen at STP?

    • Answer: The volume of 2 moles of hydrogen at STP is 44.8 L. Therefore, to react with 1 mole of oxygen, 44.8 L of hydrogen is needed.

  2. In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), what volume of hydrogen is needed to react with 1 mole of nitrogen at STP?

    • Answer: The volume of 3 moles of hydrogen at STP is 67.2 L. Therefore, to react with 1 mole of nitrogen, 67.2 L of hydrogen is needed.

  3. In the reaction of carbon (C) with oxygen (O2) to form carbon dioxide (CO2), what volume of oxygen is needed to react with 1 mole of carbon at STP?

    • Answer: The volume of 1 mole of oxygen at STP is 22.4 L. Therefore, to react with 1 mole of carbon, 22.4 L of oxygen is needed.

Difficult Problems:

  1. In the reaction of sulfur (S8) with oxygen (O2) to form sulfur dioxide (SO2), what volume of oxygen is needed to react with 0.5 moles of sulfur at STP?

    • Answer: The volume of 8 moles of oxygen at STP is 179.2 L. Therefore, to react with 0.5 moles of sulfur, 89.6 L of oxygen is needed.

  2. In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), what volume of oxygen is needed to react with 2 moles of iron at STP?

    • Answer: The volume of 1.5 moles of oxygen at STP is 33.6 L. Therefore, to react with 2 moles of iron, 33.6 L of oxygen is needed.

  3. In the reaction of aluminum (Al) with oxygen (O2) to form aluminum oxide (Al2O3), what volume of oxygen is needed to react with 2 moles of aluminum at STP?

    • Answer: The volume of 1.5 moles of oxygen at STP is 33.6 L. Therefore, to react with 2 moles of aluminum, 33.6 L of oxygen is needed.


finding the amount of heat released when a given mass of product is formed from the molar heat of reaction:


Easy Problems:

  1. In the combustion of methane (CH4), -890.4 kJ of heat is released per mole of CH4 combusted. How much heat is released when 16 g of CH4 (approximately 1 mole) is combusted?

    • Answer: -890.4 kJ of heat is released when 16 g of CH4 is combusted.

  2. In the combustion of hydrogen (H2) to form water (H2O), -285.8 kJ of heat is released per mole of H2 combusted. How much heat is released when 2 g of H2 (approximately 1 mole) is combusted?

    • Answer: -285.8 kJ of heat is released when 2 g of H2 is combusted.

  3. In the combustion of carbon (C) to form carbon dioxide (CO2), -393.5 kJ of heat is released per mole of C combusted. How much heat is released when 12 g of C (approximately 1 mole) is combusted?

    • Answer: -393.5 kJ of heat is released when 12 g of C is combusted.



Difficult Problems:

  1. In the combustion of glucose (C6H12O6), -2803 kJ of heat is released per mole of glucose combusted. How much heat is released when 90 g of glucose is combusted?

    • Answer: The molar mass of glucose is approximately 180 g/mol. Therefore, 90 g is approximately 0.5 moles. So, -1401.5 kJ of heat is released when 90 g of glucose is combusted.

  2. In the combustion of ethanol (C2H5OH), -1367 kJ of heat is released per mole of ethanol combusted. How much heat is released when 23 g of ethanol is combusted?

    • Answer: The molar mass of ethanol is approximately 46 g/mol. Therefore, 23 g is approximately 0.5 moles. So, -683.5 kJ of heat is released when 23 g of ethanol is combusted.

  3. In the combustion of propane (C3H8), -2220 kJ of heat is released per mole of propane combusted. How much heat is released when 22 g of propane is combusted?

    • Answer: The molar mass of propane is approximately 44 g/mol. Therefore, 22 g is approximately 0.5 moles. So, -1110 kJ of heat is released when 22 g of propane is combusted.



problems about predicting excess and limiting reagents:



Easy Problems:

  1. In the reaction of hydrogen (H2) with oxygen (O2) to form water (H2O), if 4 moles of H2 react with 1 mole of O2, which is the limiting reagent?

    • Answer: Oxygen (O2) is the limiting reagent because the reaction requires 2 moles of H2 for every 1 mole of O2. Therefore, there is an excess of H2.

  2. In the reaction of nitrogen (N2) with hydrogen (H2) to form ammonia (NH3), if 1 mole of N2 reacts with 2 moles of H2, which is the limiting reagent?

    • Answer: Nitrogen (N2) is the limiting reagent because the reaction requires 3 moles of H2 for every 1 mole of N2. Therefore, there is an excess of H2.

  3. In the reaction of carbon (C) with oxygen (O2) to form carbon dioxide (CO2), if 1 mole of C reacts with 1 mole of O2, which is the limiting reagent?

    • Answer: Neither is the limiting reagent because the reaction requires 1 mole of C for every 1 mole of O2. Therefore, there is no excess reagent.

Medium Difficulty Problems:

  1. In the reaction of sulfur (S8) with oxygen (O2) to form sulfur dioxide (SO2), if 1 mole of S8 reacts with 6 moles of O2, which is the limiting reagent?

    • Answer: Sulfur (S8) is the limiting reagent because the reaction requires 8 moles of O2 for every 1 mole of S8. Therefore, there is an excess of O2.

  2. In the reaction of iron (Fe) with oxygen (O2) to form iron(III) oxide (Fe2O3), if 4 moles of Fe react with 2 moles of O2, which is the limiting reagent?

    • Answer: Oxygen (O2) is the limiting reagent because the reaction requires 3 moles of O2 for every 4 moles of Fe. Therefore, there is an excess of Fe.

  3. In the reaction of aluminum (Al) with oxygen (O2) to form aluminum oxide (Al2O3), if 4 moles of Al react with 2 moles of O2, which is the limiting reagent?

    • Answer: Aluminum (Al) is the limiting reagent because the reaction requires 3 moles of O2 for every 4 moles of Al. Therefore, there is an excess of O2.

Difficult Problems:

  1. In the reaction of glucose (C6H12O6) with oxygen (O2) to form carbon dioxide (CO2) and water (H2O), if 1 mole of C6H12O6 reacts with 5 moles of O2, which is the limiting reagent?

    • Answer: Oxygen (O2) is the limiting reagent because the reaction requires 6 moles of O2 for every 1 mole of C6H12O6. Therefore, there is an excess of C6H12O6.

  2. In the reaction of ethanol (C2H5OH) with oxygen (O2) to form carbon dioxide (CO2) and water (H2O), if 1 mole of C2H5OH reacts with 2 moles of O2, which is the limiting reagent?

    • Answer: Ethanol (C2H5OH) is the limiting reagent because the reaction requires 3 moles of O2 for every 1 mole of C2H5OH. Therefore, there is an excess of O2.

  3. In the reaction of propane (C3H8) with oxygen (O2) to form carbon dioxide (CO2) and water (H2O), if 1 mole of C3H8 reacts with 4 moles of O2, which is the limiting reagent?

    • Answer: Propane (C3H8) is the limiting reagent because the reaction requires 5 moles of O2 for every 1 mole of C3H8. Therefore, there is an excess of O2.



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