The document contains multiple questions related to the calculation of empirical formulas, molarity, mass percentage, and mole fractions of various compounds and solutions. It includes specific examples with percentages and masses for different chemicals and mixtures. The material is structured as a series of problems that require chemical calculations and applications of theoretical concepts.

1. 1.What is the empirical formula of a compound containing 40.0% sulfur and 60.0% oxygen by mass?
2.A compound is found to contain 23.3% magnesium, 30.7% sulfur, and 46.0% oxygen. What is the empirical formula of this compound?
3.What is the empirical formula for a compound containing 38.8% carbon, 16.2% hydrogen, and 45.1% nitrogen?
4.A sample of an oxide of nitrogen is found to contain 30.4% nitrogen. What is its empirical formula?
5.A sample of an oxide of arsenic is found to contain 75.74% arsenic. What is its empirical formula?
6.What is the empirical formula for a compound containing 26.57% potassium, 35.36% chromium, and 38.07% oxygen?
7.What is the empirical formula of a compound comprising 1.8% hydrogen, 42.1% carbon, and 56.1% oxygen?
8.Calculate the empirical formula of a compound with 40.05% carbon, 6.71% hydrogen, and 53.24% oxygen.
9.Determine the empirical formula of a compound with 20.9% sodium, 27.3% sulfur, and 51.8% oxygen.
10.A compound is found to contain 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen. What is its empirical formula?
11.Calculate the empirical formula of a compound with 30.45% nitrogen and 69.55% oxygen.
12.What is the empirical formula of a compound containing 75.0% carbon and 25.0% hydrogen?
13.A compound is found to contain 64.8% iron and 35.2% oxygen. What is its empirical formula?
14.Determine the empirical formula of a compound with 18.2% potassium, 47.3% sulfur, and 34.5% oxygen.
15.What is the empirical formula of a compound containing 20.0% nitrogen and 80.0% oxygen by mass?

2. 1.Calculate the empirical formula of a compound with 40.8% carbon, 4.5% hydrogen, and 54.7% oxygen.
2.A compound is found to contain 30.0% phosphorus and 70.0% oxygen. What is its empirical formula?
3.Determine the empirical formula of a compound with 25.1% calcium, 10.1% phosphorus, and 64.8% oxygen.
4.What is the empirical formula of a compound containing 60.3% potassium and 39.7% chlorine?
5.Calculate the empirical formula of a compound with 15.2% aluminum, 12.1% sulfur, and 72.7% oxygen.
6.A compound is found to contain 55.0% carbon, 5.0% hydrogen, and 40.0% oxygen. What is its empirical formula?
7.Determine the empirical formula of a compound with 22.2% sodium, 11.1% sulfur, and 66.7% oxygen.
8.What is the empirical formula of a compound containing 30.0% nitrogen and 70.0% chlorine by mass?
9.Calculate the empirical formula of a compound with 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen.
10.A compound is found to contain 64.8% iron and 35.2% oxygen. What is its empirical formula?
11.Determine the empirical formula of a compound with 18.2% potassium, 47.3% sulfur, and 34.5% oxygen.
12.What is the empirical formula of a compound containing 20.0% nitrogen and 80.0% oxygen by mass?
13.Calculate the empirical formula of a compound with 40.8% carbon, 4.5% hydrogen, and 54.7% oxygen.
14.A compound is found to contain 30.0% phosphorus and 70.0% oxygen. What is its empirical formula?
15.Determine the empirical formula of a compound with 25.1% calcium, 10.1% phosphorus, and 64.8% oxygen.

3. 1.Calculate the number of moles and the number of molecules in 12g of carbon, 64g of oxygen, and 72g of water.
2.Determine the number of moles in 36g of water (H2O).
3.How many moles are present in 16g of methane (CH4)?
4.Calculate the number of moles in 90g of sulfuric acid (H2SO4).
5.Find the number of moles in 28g of nitrogen gas (N2).
6.Determine the number of moles in 80g of calcium carbonate (CaCO3).
7.How many moles are present in 58.5g of sodium chloride (NaCl)?
8.Calculate the number of moles in 18g of water (H2O).
9.Find the number of moles in 44g of carbon dioxide (CO2).
10.Determine the number of moles in 72g of sulfur dioxide (SO2).
11.How many moles are present in 32g of oxygen gas (O2)?
12.Calculate the number of moles in 58.44g of sodium bicarbonate (NaHCO3).
13.Determine the number of moles in 40g of ammonia (NH3).
14.Find the number of moles in 98g of sulfuric acid (H2SO4).
15.Calculate the number of moles in 180g of glucose (C6H12O6).
16.Determine the number of moles in 56g of iron (Fe).
17.How many moles are present in 34g of aluminum (Al)?
18.Calculate the number of moles in 72g of potassium permanganate (KMnO4).
19.Find the number of moles in 90g of calcium oxide (CaO).
20.Determine the number of moles in 58.5g of sodium chloride (NaCl).
21.How many moles are present in 32g of sulfuric acid (H2SO4)?
22.Calculate the number of moles in 18g of water (H2O).
23.Determine the number of moles in 44g of carbon dioxide (CO2).
24.Find the number of moles in 72g of sulfur dioxide (SO2).
25.Calculate the number of moles in 58.44g of sodium bicarbonate (NaHCO3).
26.Determine the number of moles in 40g of ammonia (NH3).
27.How many moles are present in 98g of sulfuric acid (H2SO4)?
28.Calculate the number of moles in 180g of glucose (C6H12O6).
29.Determine the number of moles in 56g of iron (Fe).
30.Find the number of moles in 34g of aluminum (Al).

4. 1. What is the formula for calculating the mass percentage of a solute in a solution?
2. Calculate the mass percentage of a solute in a solution if 20g of solute is dissolved in 80g of the solution.
3. Determine the mass percentage of a solute in a solution if 30g of solute is dissolved in 120g of the solution.
4. How is the mass percentage of an element in a compound calculated?
5. Calculate the mass percentage of carbon in carbon dioxide (CO2).
6. Determine the mass percentage of hydrogen in water (H2O).
7. What is the mass percentage of oxygen in sodium hydroxide (NaOH)?
8. Calculate the mass percentage of nitrogen in ammonia (NH3).
9. Determine the mass percentage of chlorine in sodium chloride (NaCl).
10. How is the mass percentage of an element in a compound related to its molar mass?
11. Calculate the mass percentage of carbon in glucose (C6H12O6).
12. Determine the mass percentage of hydrogen in methane (CH4).
13. What is the mass percentage of oxygen in sulfuric acid (H2SO4)?
14. Calculate the mass percentage of nitrogen in ammonium nitrate (NH4NO3).
15. Determine the mass percentage of chlorine in dichloroethane (C2H4Cl2).

5. 1. How is the mass percentage of an element in a compound affected by its natural abundances and isotopic masses?
2. Calculate the mass percentage of carbon in a compound with 24.3% carbon and 4.1% hydrogen.
3. Determine the mass percentage of hydrogen in a compound with 92.3% carbon and a molar mass of 78.1 g/mol.
4. What is the mass percentage of nitrogen in vanillin, given its composition of 63.56% carbon and 31.56% oxygen?
5. Calculate the mass percentage of nitrogen in a fuel with 87.4% nitrogen and 12.6% hydrogen.
6. Determine the mass percentage of sodium hydroxide in a solution obtained by mixing 100g of 30% solution with 150g of a 40% solution.
7. What is the mass percentage of benzene and carbon tetrachloride in a solution obtained by mixing 22g of benzene with 122g of carbon tetrachloride?
8. Calculate the mass percentage of a solution obtained by mixing 300g of 25% solution of NH4NO3 with 400g of a 40% solution of solute X.
9. Determine the mass percentage of sodium hydroxide in a solution obtained by mixing 100g of 30% solution with 150g of a 40% solution.
10. What is the mass percentage of benzene and carbon tetrachloride in a solution obtained by mixing 22g of benzene with 122g of carbon tetrachloride?
11. Calculate the mass percentage of a solution obtained by mixing 300g of 25% solution of NH4NO3 with 400g of a 40% solution of solute X.
12. Determine the mass percentage of sodium hydroxide in a solution obtained by mixing 100g of 30% solution with 150g of a 40% solution.
13. What is the mass percentage of benzene and carbon tetrachloride in a solution obtained by mixing 22g of benzene with 122g of carbon tetrachloride?
14. Calculate the mass percentage of a solution obtained by mixing 300g of 25% solution of NH4NO3 with 400g of a 40% solution of solute X.
15. Determine the mass percentage of sodium hydroxide in a solution obtained by mixing 100g of 30% solution with 150g of a 40% solution.

6. 1. Calculate the mole fraction of NaCl in a solution prepared by dissolving 0.100 mole of NaCl into 100.0 grams of pure H2O.
2. Determine the mole fraction of H2O in the solution described in the previous question.
3. Find the mole fraction of Methanol (CH3OH) and water in a solution prepared by dissolving 4.5g of alcohol in 40g of H2O.
4. Calculate the mole fraction of HCl and H2O in a solution of hydrochloric acid in water, containing 30% HCl by weight.
5. Determine the mole fraction of CH3OH and H2O in a solution prepared by dissolving 5.5g of alcohol in 40g of H2O.
6. Calculate the mole fraction of ethanol in water in which the mole fraction of ethanol is 0.040.
7. Determine the mole fraction of benzene in a solution containing 30% by mass in carbon tetrachloride.
8. Find the mole fraction of each component in a solution containing 25% water, 25% ethyl alcohol, and 50% acetic acid by mass.
9. Calculate the mole fraction of carbon tetrachloride in a solution containing 30% by mass of benzene.
10. Determine the mole fraction of each component in a solution containing 25% water, 25% ethyl alcohol, and 50% acetic acid by mass.
11. Find the mole fraction of NaCl in a solution prepared by dissolving 0.100 mole of NaCl into 100.0 grams of pure H2O.
12. Determine the mole fraction of H2O in the solution described in the previous question.
13. Calculate the mole fraction of Methanol (CH3OH) and water in a solution prepared by dissolving 4.5g of alcohol in 40g of H2O.
14. Determine the mole fraction of HCl and H2O in a solution of hydrochloric acid in water, containing 30% HCl by weight.
15. Calculate the mole fraction of CH3OH and H2O in a solution prepared by dissolving 5.5g of alcohol in 40g of H2O.

7. 1. Calculate the mole fraction of ethanol in water in which the mole fraction of ethanol is 0.040.
2. Determine the mole fraction of benzene in a solution containing 30% by mass in carbon tetrachloride.
3. Find the mole fraction of each component in a solution containing 25% water, 25% ethyl alcohol, and 50% acetic acid by mass.
4. Calculate the mole fraction of carbon tetrachloride in a solution containing 30% by mass of benzene.
5. Determine the mole fraction of each component in a solution containing 25% water, 25% ethyl alcohol, and 50% acetic acid by mass.
6. Calculate the mole fraction of NaCl in a solution prepared by dissolving 0.100 mole of NaCl into 100.0 grams of pure H2O.
7. Determine the mole fraction of H2O in the solution described in the previous question.
8. Calculate the mole fraction of Methanol (CH3OH) and water in a solution prepared by dissolving 4.5g of alcohol in 40g of H2O.
9. Determine the mole fraction of HCl and H2O in a solution of hydrochloric acid in water, containing 30% HCl by weight.
10. Calculate the mole fraction of CH3OH and H2O in a solution prepared by dissolving 5.5g of alcohol in 40g of H2O.
11. Calculate the mole fraction of ethanol in water in which the mole fraction of ethanol is 0.040.
12. Determine the mole fraction of benzene in a solution containing 30% by mass in carbon tetrachloride.
13. Find the mole fraction of each component in a solution containing 25% water, 25% ethyl alcohol, and 50% acetic acid by mass.
14. Calculate the mole fraction of carbon tetrachloride in a solution containing 30% by mass of benzene.
15. Determine the mole fraction of each component in a solution containing 25% water, 25% ethyl alcohol, and 50% acetic acid by mass.

8. 1. What is the definition of molarity and how is it calculated?
2. Calculate the molarity of a solution containing 5 moles of solute in 2 liters of solution.
3. Determine the molarity of a solution if 0.25 moles of solute are dissolved in 500 mL of solution.
4. How is molarity related to the number of moles of solute and the volume of the solution?
5. Calculate the molarity of a solution containing 8 grams of NaCl dissolved in 500 mL of water.
6. Determine the molarity of a solution if 0.1 moles of solute are dissolved in 250 mL of solution.
7. What is the molarity of a solution containing 10 grams of glucose (C6H12O6) in 500 mL of water?
8. Calculate the molarity of a solution containing 0.5 moles of potassium chloride (KCl) in 1 liter of water.
9. Determine the molarity of a solution if 0.2 moles of solute are dissolved in 300 mL of solution.
10. How is molarity affected by changes in the amount of solute or the volume of the solution?

9. 1. Calculate the molarity of a solution containing 3 moles of solute in 1.5 liters of solution.
2. Determine the molarity of a solution if 0.15 moles of solute are dissolved in 200 mL of solution.
3. What is the molarity of a solution containing 15 grams of sucrose (C12H22O11) in 750 mL of water?
4. Calculate the molarity of a solution containing 0.8 moles of calcium chloride (CaCl2) in 2 liters of water.
5. Determine the molarity of a solution if 0.3 moles of solute are dissolved in 400 mL of solution.
6. How does molarity relate to the concentration of a solution and its dilution?
7. Calculate the molarity of a solution containing 4 moles of solute in 2.5 liters of solution.
8. Determine the molarity of a solution if 0.2 moles of solute are dissolved in 300 mL of solution.
9. What is the molarity of a solution containing 20 grams of potassium nitrate (KNO3) in 1 liter of water?
10. Calculate the molarity of a solution containing 1 mole of solute in 500 mL of water.
11. Determine the molarity of a solution if 0.25 moles of solute are dissolved in 400 mL of solution.
12. How is molarity affected by changes in the temperature and pressure of a solution?
13. Calculate the molarity of a solution containing 6 moles of solute in 3 liters of solution.
14. Determine the molarity of a solution if 0.3 moles of solute are dissolved in 500 mL of solution.
15. What is the molarity of a solution containing 25 grams of sodium carbonate (Na2CO3) in 1.5 liters of water?
16. Calculate the molarity of a solution containing 1.5 moles of solute in 750 mL of water.
17. Determine the molarity of a solution if 0.4 moles of solute are dissolved in 600 mL of solution.
18. How does molarity play a role in chemical reactions and stoichiometry?
19. Calculate the molarity of a solution containing 7 moles of solute in 4 liters of solution.
20. Determine the molarity of a solution if 0.5 moles of solute are dissolved in 800 mL of solution.

10. 1. An aqueous solution of urea containing 18g urea in 1500 cm3 of the solution has a density equal to 1.052. If the molecular weight of urea is 60, what is the molality of the solution?
2. Calculate the molality of a solution containing 16.5 g of naphthalene (C10H8) in 54.3 g benzene (C6H6).
3. Calculate the molality (m) of a 7.55 kg sample of a solution of the solute CH2Cl2 (molar mass = 84.93 g/mol) dissolved in the solvent acetone (CH3COCH3) if the sample contains 929 g of methylene chloride.
4. 560 g of a 2 m aqueous solution of urea is mixed with 2480 g of a 4 m aqueous solution of urea. What is the molality of the resulting solution?
5. What is the molality of NaCl in an aqueous solution in which the mole fraction of NaCl is 0.100?
6. An experiment in a general chemistry laboratory calls for a 2.00-M solution of HCl. How many mL of 11.9 M HCl would be required to make 250 mL of 2.00 M HCl?
7. Find the molality of a solution made by mixing equal volumes of 60% (w/w) H2SO4 (density = 1.84 g/mL) and 40% (w/w) of H2SO4 (density = 1.52 g/mL) solutions.
8. What is the number of moles of solute in 250 mL of a 0.4 M solution?
9. Calculate the molality of a solution containing 30 mL of methanol (density 0.7980 g/mL) mixed with 70 mL of water.
10. A solution is prepared by dissolving 25 g of glucose (C6H12O6) in 500 g of water. Calculate the molality of the solution.
11. Calculate the molality of a solution containing 0.5 moles of glucose (C6H12O6) dissolved in 500 g of water.
12. A solution is prepared by dissolving 10 g of sodium chloride (NaCl) in 100 g of water. Calculate the molality of the solution.
13. Calculate the molality of a solution containing 0.2 moles of sodium chloride (NaCl) dissolved in 200 g of water.
14. A solution is prepared by dissolving 5 g of potassium nitrate (KNO3) in 100 g of water. Calculate the molality of the solution.
15. Calculate the molality of a solution containing 0.1 moles of potassium nitrate (KNO3) dissolved in 200 g of water.

11. 1. A solution is prepared by dissolving 15 g of sucrose (C12H22O11) in 200 g of water. Calculate the molality of the solution.
2. Calculate the molality of a solution containing 0.3 moles of sucrose (C12H22O11) dissolved in 300 g of water.
3. A solution is prepared by dissolving 8 g of ammonium chloride (NH4Cl) in 100 g of water. Calculate the molality of the solution.
4. Calculate the molality of a solution containing 0.4 moles of ammonium chloride (NH4Cl) dissolved in 200 g of water.
5. A solution is prepared by dissolving 12 g of calcium chloride (CaCl2) in 150 g of water. Calculate the molality of the solution.
6. Calculate the molality of a solution containing 0.6 moles of calcium chloride (CaCl2) dissolved in 250 g of water.
7. A solution is prepared by dissolving 6 g of magnesium sulfate (MgSO4) in 100 g of water. Calculate the molality of the solution.
8. Calculate the molality of a solution containing 0.2 moles of magnesium sulfate (MgSO4) dissolved in 200 g of water.
9. A solution is prepared by dissolving 10 g of potassium permanganate (KMnO4) in 150 g of water. Calculate the molality of the solution.
10. Calculate the molality of a solution containing 0.3 moles of potassium permanganate (KMnO4) dissolved in 250 g of water.
11. A solution is prepared by dissolving 8 g of copper sulfate (CuSO4) in 100 g of water. Calculate the molality of the solution.
12. Calculate the molality of a solution containing 0.4 moles of copper sulfate (CuSO4) dissolved in 200 g of water.
13. A solution is prepared by dissolving 12 g of silver nitrate (AgNO3) in 150 g of water. Calculate the molality of the solution.
14. Calculate the molality of a solution containing 0.6 moles of silver nitrate (AgNO3) dissolved in 250 g of water.
15. A solution is prepared by dissolving 6 g of iron(III) chloride (FeCl3) in 100 g of water. Calculate the molality of the solution.

12. 1. An aqueous solution of urea has a density of 1.15 g/mL. If the molecular weight of urea is 60 g/mol, what is the molarity of the solution?
2. A solution of concentrated HCl has a density of 1.0745 g/cm3. What is the molarity of the solution?
3. An aqueous solution of H2SO4 has a molal concentration of 8.010 m and a density of 1.354 g/mL. What is the molar concentration of the solution?
4. A solution of H2SO4 with a density of 1.230 g/mL has a molar concentration of 3.75 M. What is the molality of the solution?
5. An aqueous solution of NaOH has a density of 1.038 g/cm3. Calculate the molarity, molality, and mole fraction of NaOH in water.
6. A solution of HNO3 has a density of 1.04 g/cm3. If the mass percent of HNO3 is 12.2%, calculate the molarity, molality, and mole fraction of HNO3 in the solution.
7. An aqueous solution of sulphuric acid is 29% H2SO4 by mass. What is the density of a 3.60 M sulphuric acid solution?
8. A 2.00-L bottle of a solution of concentrated HCl contains 868.8 g of HCl. What is the molarity of the solution?
9. How many mL of 11.9 M HCl are required to make 250 mL of a 2.00 M HCl solution?
10. What is the maximum permissible molarity of potassium dichromate (K2Cr2O7) if the limit for hexavalent chromium is 0.50 mg/L?

13. 1. Calculate the molarity of a solution if 3.30 mL of acetone (density = 0.789 g/mL) is diluted with water to a final volume of 75.0 mL. The density of the solution is 0.993 g/mL.
2. An aqueous solution of NaOH has a density of 1.354 g/mL. If the molecular weight of NaOH is 40 g/mol, what is the molarity of the solution?
3. A solution of HCl has a density of 1.230 g/mL. If the molecular weight of HCl is 36.5 g/mol, what is the molarity of the solution?
4. An aqueous solution of HNO3 has a density of 1.04 g/cm3. If the mass percent of HNO3 is 12.2%, what is the molarity of the solution?
5. A solution of H2SO4 has a density of 1.04 g/cm3. If the mass percent of H2SO4 is 29%, what is the molarity of the solution?
6. An aqueous solution of NaCl has a density of 1.15 g/mL. If the molecular weight of NaCl is 58.5 g/mol, what is the molarity of the solution?
7. A solution of glucose (C6H12O6) has a density of 1.10 g/mL. If the molecular weight of glucose is 180 g/mol, what is the molarity of the solution?
8. An aqueous solution of sucrose (C12H22O11) has a density of 1.20 g/mL. If the molecular weight of sucrose is 342 g/mol, what is the molarity of the solution?
9. A solution of NaOH has a density of 1.50 g/mL. If the molecular weight of NaOH is 40 g/mol, what is the molarity of the solution?
10. An aqueous solution of HCl has a density of 1.20 g/mL. If the molecular weight of HCl is 36.5 g/mol, what is the molarity of the solution?
11. A solution of NaCl has a density of 1.10 g/mL. If the molecular weight of NaCl is 58.5 g/mol, what is the molarity of the solution?

14. 1. An aqueous solution of urea has a density of 1.15 g/mL. If the molecular weight of urea is 60 g/mol and the mass percent of urea is 10%, what is the molarity of the solution?
2. A solution of concentrated HCl has a density of 1.0745 g/cm3 and a mass percent of 36.5%. What is the molarity of the solution?
3. An aqueous solution of H2SO4 has a density of 1.354 g/mL and a mass percent of 20%. What is the molar concentration of the solution?
4. A solution of H2SO4 with a density of 1.230 g/mL and a mass percent of 29% has a molar concentration of 3.75 M. What is the molality of the solution?
5. An aqueous solution of NaOH has a density of 1.038 g/cm3 and a mass percent of 10%. Calculate the molarity, molality, and mole fraction of NaOH in water.
6. A solution of HNO3 has a density of 1.04 g/cm3 and a mass percent of 12.2%. Calculate the molarity, molality, and mole fraction of HNO3 in the solution.
7. An aqueous solution of sulphuric acid is 29% H2SO4 by mass and has a molar concentration of 3.60 M. What is the density of the solution?
8. A 2.00-L bottle of a solution of concentrated HCl contains 868.8 g of HCl. What is the molarity of the solution if the mass percent of HCl is 36.5%?
9. How many mL of 11.9 M HCl are required to make 250 mL of a 2.00 M HCl solution if the density of the 11.9 M HCl solution is 1.20 g/mL?
10. What is the maximum permissible molarity of potassium dichromate (K2Cr2O7) if the limit for hexavalent chromium is 0.50 mg/L and the density of the solution is 1.15 g/mL?
11. There is about 1.0 g of calcium (as Ca2+) in 1.0 L of milk. What is the molarity of Ca2+ in milk if the density of milk is 1.03 g/mL and the mass percent of Ca2+ is 0.1%?
12. An aqueous solution of NaOH is marked 10% (w/w) and has a density of 1.070 g/cm3. Calculate the molarity, molality, and mole fraction of NaOH in water.
13. What is the molarity of a 30.0% (w/w) hydrogen peroxide solution with a density of 1.11 g/mL?
14. Calculate the molarity of a 15.00 M HCl solution with a density of 1.0745 g/cm3.
15. An aqueous solution of H2SO4 is diluted to a final volume of 75.0 mL. The density of the solution is 0.993 g/mL and the mass percent of H2SO4 is 20%. Calculate the molarity, molality, and mole fraction of acetone in the solution.
16. Calculate the molarity, molality, and mole fraction of a solution made by mixing equal volumes of 30% H2SO4 (density = 1.218 g/mL) and 70% H2SO4 (density = 1.610 g/mL) solutions.