Answer the following questions a) How many atoms are in 0.5 moles of Sodium (Na)?(1) b) How many atoms are in 0.45 grams of Iron?(1) c) How many molecules are in 0.75 moles of H2O?(1) d) CH4 has 3.01 x 1023 molecules, Calculate its number of moles.(2)

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Asked on June 9, 2026Chemistry

This chemistry question involves key chemical concepts and calculations. The detailed solution below walks through each step, from identifying the reaction type to computing the final answer.

Accepted Answer · 2026-06-09T18:39:32.863Z

Here are the solutions to questions 5, 6, 7, 8, and 9. Question 5: Given: Mass of Magnesium (Mg) = 24 grams. Atomic mass of Mg = 24.305 g/mol. (Using a more precise value for calculations) a) Calculate the number of moles of magnesium present. Step 1: Use the formula for moles. Moles = MassMolar mass Step 2: Substitute the given values. Moles of Mg = 24 g24.305 g/mol Moles of Mg ≈ 0.987 mol The number of moles of magnesium present is 0.987 mol. b) Determine the number of atoms in the sample. Step 1: Use Avogadro's number (6.022 × 10^23 atoms/mol). Number of atoms = Moles × Avogadro's number Step 2: Substitute the calculated moles. Number of atoms of Mg = 0.987 mol × (6.022 × 10^23 atoms/mol) Number of atoms of Mg ≈ 5.944 × 10^23 atoms The number of atoms in the sample is 5.944 × 10^23 atoms. Question 6: Given: Mass of Sodium chloride (NaCl) = 58.5 grams. Atomic mass of Na = 22.99 g/mol. Atomic mass of Cl = 35.45 g/mol. a) Calculate the molar mass of Sodium chloride. Step 1: Sum the atomic masses of Na and Cl. Molar mass of NaCl = Atomic mass of Na + Atomic mass of Cl Molar mass of NaCl = 22.99 g/mol + 35.45 g/mol Molar mass of NaCl = 58.44 g/mol The molar mass of Sodium chloride is 58.44 g/mol. b) Determine the number of moles present. Step 1: Use the formula for moles. Moles = MassMolar mass Step 2: Substitute the given mass and calculated molar mass. Moles of NaCl = 58.5 g58.44 g/mol Moles of NaCl ≈ 1.001 mol The number of moles present is 1.001 mol. c) Calculate the number of ions if the salt completely dissociates in water. Step 1: Determine the number of ions per formula unit. NaCl dissociates into Na^+ and Cl^-, so there are 2 ions per formula unit. Step 2: Calculate the total number of formula units. Number of formula units = Moles × Avogadro's number Number of formula units of NaCl = 1.001 mol × (6.022 × 10^23 formula units/mol) Number of formula units of NaCl ≈ 6.028 × 10^23 formula units Step 3: Calculate the total number of ions. Number of ions = Number of formula units × 2 Number of ions = (6.028 × 10^23) × 2 Number of ions ≈ 1.206 × 10^24 ions The number of ions is 1.206 × 10^24 ions. Question 7: Given: Mass of Lead nitrate Pb(NO_3)_2 = 98 grams. Atomic mass of Pb = 207.2 g/mol. Atomic mass of N = 14.01 g/mol. Atomic mass of O = 16.00 g/mol. a) Calculate the molar mass of Pb(NO_3)_2. Step 1: Sum the atomic masses of all atoms in the formula. Molar mass of Pb(NO_3)_2 = Atomic mass of Pb + 2 × (Atomic mass of N + 3 × Atomic mass of O) Molar mass of Pb(NO_3)_2 = 207.2 g/mol + 2 × (14.01 g/mol + 3 × 16.00 g/mol) Molar mass of Pb(NO_3)_2 = 207.2 g/mol + 2 × (14.01 g/mol + 48.00 g/mol) Molar mass of Pb(NO_3)_2 = 207.2 g/mol + 2 × (62.01 g/mol) Molar mass of Pb(NO_3)_2 = 207.2 g/mol + 124.02 g/mol Molar mass of Pb(NO_3)_2 = 331.22 g/mol The molar mass of Pb(NO_3)_2 is 331.22 g/mol. b) Determine the number of moles present. Step 1: Use the formula for moles. Moles = MassMolar mass Step 2: Substitute the given mass and calculated molar mass. Moles of Pb(NO_3)_2 = 98 g331.22 g/mol Moles of Pb(NO_3)_2 ≈ 0.296 mol The number of moles present is 0.296 mol. c) Find the number of formula units in the sample. Step 1: Use Avogadro's number. Number of formula units = Moles × Avogadro's number Step 2: Substitute the calculated moles. Number of formula units of Pb(NO_3)_2 = 0.296 mol × (6.022 × 10^23 formula units/mol) Number of formula units of Pb(NO_3)_2 ≈ 1.783 × 10^23 formula units The number of formula units in the sample is 1.783 × 10^23 formula units. Question 8: Given: Mass of Sulfuric acid (H_2SO_4) = 49 grams. Atomic mass of H = 1.008 g/mol. Atomic mass of S = 32.07 g/mol. Atomic mass of O = 16.00 g/mol. a) Calculate the molar mass of H_2SO_4. Step 1: Sum the atomic masses of all atoms in the formula. Molar mass of H_2SO_4 = (2 × Atomic mass of H) + Atomic mass of S + (4 × Atomic mass of O) Molar mass of H_2SO_4 = (2 × 1.008 g/mol) + 32.07 g/mol + (4 × 16.00 g/mol) Molar mass of H_2SO_4 = 2.016 g/mol + 32.07 g/mol + 64.00 g/mol Molar mass of H_2SO_4 = 98.086 g/mol The molar mass of H_2SO_4 is 98.086 g/mol. b) Calculate the number of moles present. Step 1: Use the formula for moles. Moles = MassMolar mass Step 2: Substitute the given mass and calculated molar mass. Moles of H_2SO_4 = 49 g98.086 g/mol Moles of H_2SO_4 ≈ 0.4995 mol The number of moles present is 0.4995 mol. c) Determine the number of molecules in the sample. Step 1: Use Avogadro's number. Number of molecules = Moles × Avogadro's number Step 2: Substitute the calculated moles. Number of molecules of H_2SO_4 = 0.4995 mol × (6.022 × 10^23 molecules/mol) Number of molecules of H_2SO_4 ≈ 3.008 × 10^23 molecules The number of molecules in the sample is 3.008 × 10^23 molecules. Question 9: a) How many atoms are in 0.5 moles of Sodium (Na)? Step 1: Use Avogadro's number. Number of atoms = Moles × Avogadro's number Step 2: Substitute the given moles. Number of atoms of Na = 0.5 mol × (6.022 × 10^23 atoms/mol) Number of atoms of Na = 3.011 × 10^23 atoms There are 3.011 × 10^23 atoms in 0.5 moles of Sodium. b) How many atoms are in 0.45 grams of Iron (Fe)? Atomic mass of Fe = 55.845 g/mol. Step 1: Calculate the number of moles of Fe. Moles of Fe = MassMolar mass = 0.45 g55.845 g/mol Moles of Fe ≈ 0.008058 mol Step 2: Calculate the number of atoms. Number of atoms of Fe = 0.008058 mol × (6.022 × 10^23 atoms/mol) Number of atoms of Fe ≈ 4.852 × 10^21 atoms There are 4.852 × 10^21 atoms in 0.45 grams of Iron. c) How many molecules are in 0.75 moles of H_2O? Step 1: Use Avogadro's number. Number of molecules = Moles × Avogadro's number Step 2: Substitute the given moles. Number of molecules of H_2O = 0.75 mol × (6.022 × 10^23 molecules/mol) Number of molecules of H_2O = 4.5165 × 10^23 molecules There are 4.5165 × 10^23 molecules in 0.75 moles of H_2O. d) CH_4 has 3.01 × 10^23 molecules. Calculate its number of moles. Step 1: Use Avogadro's number to convert molecules to moles. Moles = Number of moleculesAvogadro's number Step 2: Substitute the given number of molecules. Moles of CH_4 = 3.01 × 10^23 molecules6.022 × 10^23 molecules/mol Moles of CH_4 ≈ 0.4998 mol The number of moles of CH_4 is 0.4998 mol. What's next? 📸

Accepted Answer · 2026-06-09T18:39:32.863Z

Here are the solutions to questions 5, 6, 7, 8, and 9. Question 5: Given: Mass of Magnesium (Mg) = 24 grams. Atomic mass of Mg = 24.305 g/mol. (Using a more precise value for calculations) a) Calculate the number of moles of magnesium present. Step 1: Use the formula for moles. Moles = MassMolar mass Step 2: Substitute the given values. Moles of Mg = 24 g24.305 g/mol Moles of Mg ≈ 0.987 mol The number of moles of magnesium present is 0.987 mol. b) Determine the number of atoms in the sample. Step 1: Use Avogadro's number (6.022 × 10^23 atoms/mol). Number of atoms = Moles × Avogadro's number Step 2: Substitute the calculated moles. Number of atoms of Mg = 0.987 mol × (6.022 × 10^23 atoms/mol) Number of atoms of Mg ≈ 5.944 × 10^23 atoms The number of atoms in the sample is 5.944 × 10^23 atoms. Question 6: Given: Mass of Sodium chloride (NaCl) = 58.5 grams. Atomic mass of Na = 22.99 g/mol. Atomic mass of Cl = 35.45 g/mol. a) Calculate the molar mass of Sodium chloride. Step 1: Sum the atomic masses of Na and Cl. Molar mass of NaCl = Atomic mass of Na + Atomic mass of Cl Molar mass of NaCl = 22.99 g/mol + 35.45 g/mol Molar mass of NaCl = 58.44 g/mol The molar mass of Sodium chloride is 58.44 g/mol. b) Determine the number of moles present. Step 1: Use the formula for moles. Moles = MassMolar mass Step 2: Substitute the given mass and calculated molar mass. Moles of NaCl = 58.5 g58.44 g/mol Moles of NaCl ≈ 1.001 mol The number of moles present is 1.001 mol. c) Calculate the number of ions if the salt completely dissociates in water. Step 1: Determine the number of ions per formula unit. NaCl dissociates into Na^+ and Cl^-, so there are 2 ions per formula unit. Step 2: Calculate the total number of formula units. Number of formula units = Moles × Avogadro's number Number of formula units of NaCl = 1.001 mol × (6.022 × 10^23 formula units/mol) Number of formula units of NaCl ≈ 6.028 × 10^23 formula units Step 3: Calculate the total number of ions. Number of ions = Number of formula units × 2 Number of ions = (6.028 × 10^23) × 2 Number of ions ≈ 1.206 × 10^24 ions The number of ions is 1.206 × 10^24 ions. Question 7: Given: Mass of Lead nitrate Pb(NO_3)_2 = 98 grams. Atomic mass of Pb = 207.2 g/mol. Atomic mass of N = 14.01 g/mol. Atomic mass of O = 16.00 g/mol. a) Calculate the molar mass of Pb(NO_3)_2. Step 1: Sum the atomic masses of all atoms in the formula. Molar mass of Pb(NO_3)_2 = Atomic mass of Pb + 2 × (Atomic mass of N + 3 × Atomic mass of O) Molar mass of Pb(NO_3)_2 = 207.2 g/mol + 2 × (14.01 g/mol + 3 × 16.00 g/mol) Molar mass of Pb(NO_3)_2 = 207.2 g/mol + 2 × (14.01 g/mol + 48.00 g/mol) Molar mass of Pb(NO_3)_2 = 207.2 g/mol + 2 × (62.01 g/mol) Molar mass of Pb(NO_3)_2 = 207.2 g/mol + 124.02 g/mol Molar mass of Pb(NO_3)_2 = 331.22 g/mol The molar mass of Pb(NO_3)_2 is 331.22 g/mol. b) Determine the number of moles present. Step 1: Use the formula for moles. Moles = MassMolar mass Step 2: Substitute the given mass and calculated molar mass. Moles of Pb(NO_3)_2 = 98 g331.22 g/mol Moles of Pb(NO_3)_2 ≈ 0.296 mol The number of moles present is 0.296 mol. c) Find the number of formula units in the sample. Step 1: Use Avogadro's number. Number of formula units = Moles × Avogadro's number Step 2: Substitute the calculated moles. Number of formula units of Pb(NO_3)_2 = 0.296 mol × (6.022 × 10^23 formula units/mol) Number of formula units of Pb(NO_3)_2 ≈ 1.783 × 10^23 formula units The number of formula units in the sample is 1.783 × 10^23 formula units. Question 8: Given: Mass of Sulfuric acid (H_2SO_4) = 49 grams. Atomic mass of H = 1.008 g/mol. Atomic mass of S = 32.07 g/mol. Atomic mass of O = 16.00 g/mol. a) Calculate the molar mass of H_2SO_4. Step 1: Sum the atomic masses of all atoms in the formula. Molar mass of H_2SO_4 = (2 × Atomic mass of H) + Atomic mass of S + (4 × Atomic mass of O) Molar mass of H_2SO_4 = (2 × 1.008 g/mol) + 32.07 g/mol + (4 × 16.00 g/mol) Molar mass of H_2SO_4 = 2.016 g/mol + 32.07 g/mol + 64.00 g/mol Molar mass of H_2SO_4 = 98.086 g/mol The molar mass of H_2SO_4 is 98.086 g/mol. b) Calculate the number of moles present. Step 1: Use the formula for moles. Moles = MassMolar mass Step 2: Substitute the given mass and calculated molar mass. Moles of H_2SO_4 = 49 g98.086 g/mol Moles of H_2SO_4 ≈ 0.4995 mol The number of moles present is 0.4995 mol. c) Determine the number of molecules in the sample. Step 1: Use Avogadro's number. Number of molecules = Moles × Avogadro's number Step 2: Substitute the calculated moles. Number of molecules of H_2SO_4 = 0.4995 mol × (6.022 × 10^23 molecules/mol) Number of molecules of H_2SO_4 ≈ 3.008 × 10^23 molecules The number of molecules in the sample is 3.008 × 10^23 molecules. Question 9: a) How many atoms are in 0.5 moles of Sodium (Na)? Step 1: Use Avogadro's number. Number of atoms = Moles × Avogadro's number Step 2: Substitute the given moles. Number of atoms of Na = 0.5 mol × (6.022 × 10^23 atoms/mol) Number of atoms of Na = 3.011 × 10^23 atoms There are 3.011 × 10^23 atoms in 0.5 moles of Sodium. b) How many atoms are in 0.45 grams of Iron (Fe)? Atomic mass of Fe = 55.845 g/mol. Step 1: Calculate the number of moles of Fe. Moles of Fe = MassMolar mass = 0.45 g55.845 g/mol Moles of Fe ≈ 0.008058 mol Step 2: Calculate the number of atoms. Number of atoms of Fe = 0.008058 mol × (6.022 × 10^23 atoms/mol) Number of atoms of Fe ≈ 4.852 × 10^21 atoms There are 4.852 × 10^21 atoms in 0.45 grams of Iron. c) How many molecules are in 0.75 moles of H_2O? Step 1: Use Avogadro's number. Number of molecules = Moles × Avogadro's number Step 2: Substitute the given moles. Number of molecules of H_2O = 0.75 mol × (6.022 × 10^23 molecules/mol) Number of molecules of H_2O = 4.5165 × 10^23 molecules There are 4.5165 × 10^23 molecules in 0.75 moles of H_2O. d) CH_4 has 3.01 × 10^23 molecules. Calculate its number of moles. Step 1: Use Avogadro's number to convert molecules to moles. Moles = Number of moleculesAvogadro's number Step 2: Substitute the given number of molecules. Moles of CH_4 = 3.01 × 10^23 molecules6.022 × 10^23 molecules/mol Moles of CH_4 ≈ 0.4998 mol The number of moles of CH_4 is 0.4998 mol. What's next? 📸

Answer the following questions a) How many atoms are in 0.5 moles of Sodium (Na)?(1) b) How many atoms are in 0.45 grams of Iron?(1) c) How many molecules are in 0.75 moles of H2O?(1) d) CH4 has 3.01 x 1023 molecules, Calculate its number of moles.(2)

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Answer the following questions a) How many atoms are in 0.5 moles of Sodium (Na)?(1) b) How many atoms are in 0.45 grams of Iron?(1) c) How many molecules are in 0.75 moles of H2O?(1) d) CH4 has 3.01 x 1023 molecules, Calculate its number of moles.(2)

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