AP Chemistry Flashcards: Moles And Molar Mass

What this deck covers

This deck focuses on Moles And Molar Mass, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

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Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: How many atoms are in 1 mole of carbon?

Answer: $6.022 \times 10^{23}$ atoms. One mole contains Avogadro's number of atoms.

Flashcard 2: Find the number of moles in 75 g of C₆H₆.

Answer: 0.96 moles. 75 g ÷ 78.12 g/mol = 0.96 mol

Flashcard 3: What is the formula for number of particles?

Answer: Particles = moles $\times$ Avogadro's number. Converts moles to individual particles.

Flashcard 4: What is the molar mass of CH₄?

Answer: 16.04 g/mol. C = 12.01, H = 1.01: $12.01 + (4 \times 1.01)$

Flashcard 5: Find the number of moles in 90 g of C₂H₅OH.

Answer: 1.96 moles. 90 g ÷ 46.08 g/mol = 1.96 mol

Flashcard 6: Find the number of moles in 75 g of C₆H₆.

Answer: 0.96 moles. 75 g ÷ 78.12 g/mol = 0.96 mol

Flashcard 7: Find the number of moles in 90 g of C₂H₅OH.

Answer: 1.96 moles. 90 g ÷ 46.08 g/mol = 1.96 mol

Flashcard 8: What is the molar mass of H₂O?

Answer: 18.02 g/mol. H = 1.01, O = 16.00: $(2 \times 1.01) + 16.00$

Flashcard 9: Convert 3 moles of Na to grams.

Answer: 68.97 grams. 3 mol × 22.99 g/mol = 68.97 g

Flashcard 10: Calculate moles in 50 g of CO.

Answer: 1.79 moles. 50 g ÷ 28.01 g/mol = 1.79 mol

Flashcard 11: What is the molar mass of Fe₂O₃?

Answer: 159.69 g/mol. Fe = 55.85, O = 16.00: $(2 \times 55.85) + (3 \times 16.00)$

Flashcard 12: State Avogadro's number.

Answer: $6.022 \times 10^{23}$. The number of particles in one mole.

Flashcard 13: What is the molar mass of Al₂O₃?

Answer: 101.96 g/mol. Al = 26.98, O = 16.00: $(2 \times 26.98) + (3 \times 16.00)$

Flashcard 14: Determine moles in 4.5 grams of H₂.

Answer: 2.23 moles. 4.5 g ÷ 2.02 g/mol = 2.23 mol

Flashcard 15: Convert 3 moles of Na to grams.

Answer: 68.97 grams. 3 mol × 22.99 g/mol = 68.97 g

Flashcard 16: Calculate number of molecules in 2 moles of CO₂.

Answer: $1.204 \times 10^{24}$ molecules. 2 mol × $6.022 \times 10^{23}$ = $1.204 \times 10^{24}$

Flashcard 17: What is the formula for molar mass?

Answer: Molar mass = mass / moles. Rearranged from moles = mass/molar mass.

Flashcard 18: How many grams are in 0.5 moles of NaCl?

Answer: 29.22 grams. 0.5 mol × 58.44 g/mol = 29.22 g

Flashcard 19: Calculate mass of 0.75 moles of KBr.

Answer: 89.25 grams. 0.75 mol × 119.0 g/mol = 89.25 g

Flashcard 20: What is molar mass?

Answer: The mass of one mole of a substance, in g/mol. Connects mass to amount of substance.

Flashcard 21: Calculate mass of 2 moles of H₂SO₄.

Answer: 196.16 grams. 2 mol × 98.08 g/mol = 196.16 g

Flashcard 22: Calculate the moles in 32 grams of O₂.

Answer: 1 mole. 32 g ÷ 32.00 g/mol = 1 mol

Flashcard 23: Determine moles in 4.5 grams of H₂.

Answer: 2.23 moles. 4.5 g ÷ 2.02 g/mol = 2.23 mol

Flashcard 24: Determine moles in 150 g of H₂O.

Answer: 8.33 moles. 150 g ÷ 18.02 g/mol = 8.33 mol

Flashcard 25: How many molecules in 0.25 moles of H₂O?

Answer: $1.506 \times 10^{23}$ molecules. 0.25 mol × $6.022 \times 10^{23}$ = $1.506 \times 10^{23}$

Flashcard 26: What is the molar mass of Fe₂O₃?

Answer: 159.69 g/mol. Fe = 55.85, O = 16.00: $(2 \times 55.85) + (3 \times 16.00)$

Flashcard 27: Convert 3 moles of Na to grams.

Answer: 68.97 grams. 3 mol × 22.99 g/mol = 68.97 g

Flashcard 28: What is the molar mass of C₂H₄?

Answer: 28.05 g/mol. C = 12.01, H = 1.01: $(2 \times 12.01) + (4 \times 1.01)$

Flashcard 29: How many grams in 0.2 moles of H₂SO₄?

Answer: 19.62 grams. 0.2 mol × 98.08 g/mol = 19.62 g

Flashcard 30: Find the number of moles in 90 g of C₂H₅OH.

Answer: 1.96 moles. 90 g ÷ 46.08 g/mol = 1.96 mol

Flashcard 31: How many grams are in 0.5 moles of NaCl?

Answer: 29.22 grams. 0.5 mol × 58.44 g/mol = 29.22 g

Flashcard 32: Calculate moles in 50 g of CO.

Answer: 1.79 moles. 50 g ÷ 28.01 g/mol = 1.79 mol

Flashcard 33: What is the molar mass of H₂O?

Answer: 18.02 g/mol. H = 1.01, O = 16.00: $(2 \times 1.01) + 16.00$

Flashcard 34: Find the molar mass of C₃H₈.

Answer: 44.10 g/mol. C = 12.01, H = 1.01: $(3 \times 12.01) + (8 \times 1.01)$

Flashcard 35: How many moles are in 18 grams of water?

Answer: 1 mole. 18 g ÷ 18.02 g/mol = 1 mol

Flashcard 36: How many molecules in 0.25 moles of H₂O?

Answer: $1.506 \times 10^{23}$ molecules. 0.25 mol × $6.022 \times 10^{23}$ = $1.506 \times 10^{23}$

Flashcard 37: What is the molar mass of C₂H₄?

Answer: 28.05 g/mol. C = 12.01, H = 1.01: $(2 \times 12.01) + (4 \times 1.01)$

Flashcard 38: What is the molar mass of CO₂?

Answer: 44.01 g/mol. C = 12.01, O = 16.00: $12.01 + (2 \times 16.00)$

Flashcard 39: Calculate mass of 0.75 moles of KBr.

Answer: 89.25 grams. 0.75 mol × 119.0 g/mol = 89.25 g

Flashcard 40: What is the molar mass of NH₃?

Answer: 17.03 g/mol. N = 14.01, H = 1.01: $14.01 + (3 \times 1.01)$

Flashcard 41: How many moles are in 18 grams of water?

Answer: 1 mole. 18 g ÷ 18.02 g/mol = 1 mol

Flashcard 42: How is molar mass calculated?

Answer: Sum of atomic masses in a molecule, in g/mol. Add all atomic masses from the formula.

Flashcard 43: How many atoms are in 1 mole of carbon?

Answer: $6.022 \times 10^{23}$ atoms. One mole contains Avogadro's number of atoms.

Flashcard 44: What is the molar mass of CH₄?

Answer: 16.04 g/mol. C = 12.01, H = 1.01: $12.01 + (4 \times 1.01)$

Flashcard 45: What is the molar mass of NaCl?

Answer: 58.44 g/mol. Na = 22.99, Cl = 35.45: $22.99 + 35.45$

Flashcard 46: What is the molar mass of NaCl?

Answer: 58.44 g/mol. Na = 22.99, Cl = 35.45: $22.99 + 35.45$

Flashcard 47: How many molecules in 0.25 moles of H₂O?

Answer: $1.506 \times 10^{23}$ molecules. 0.25 mol × $6.022 \times 10^{23}$ = $1.506 \times 10^{23}$

Flashcard 48: Calculate mass of 2 moles of H₂SO₄.

Answer: 196.16 grams. 2 mol × 98.08 g/mol = 196.16 g

Flashcard 49: What is the molar mass of H₃PO₄?

Answer: 97.99 g/mol. H = 1.01, P = 30.97, O = 16.00: $(3 \times 1.01) + 30.97 + (4 \times 16.00)$

Flashcard 50: Calculate number of molecules in 2 moles of CO₂.

Answer: $1.204 \times 10^{24}$ molecules. 2 mol × $6.022 \times 10^{23}$ = $1.204 \times 10^{24}$

Flashcard 51: What is the molar mass of H₂O?

Answer: 18.02 g/mol. H = 1.01, O = 16.00: $(2 \times 1.01) + 16.00$

Flashcard 52: What is the molar mass of Al₂O₃?

Answer: 101.96 g/mol. Al = 26.98, O = 16.00: $(2 \times 26.98) + (3 \times 16.00)$

Flashcard 53: What is the molar mass of NH₃?

Answer: 17.03 g/mol. N = 14.01, H = 1.01: $14.01 + (3 \times 1.01)$

Flashcard 54: Calculate the moles in 32 grams of O₂.

Answer: 1 mole. 32 g ÷ 32.00 g/mol = 1 mol

Flashcard 55: Calculate the moles in 32 grams of O₂.

Answer: 1 mole. 32 g ÷ 32.00 g/mol = 1 mol

Flashcard 56: What is the molar mass of C₂H₄?

Answer: 28.05 g/mol. C = 12.01, H = 1.01: $(2 \times 12.01) + (4 \times 1.01)$

Flashcard 57: How many grams in 0.2 moles of H₂SO₄?

Answer: 19.62 grams. 0.2 mol × 98.08 g/mol = 19.62 g

Flashcard 58: What is the definition of a mole in chemistry?

Answer: A mole is $6.022 \times 10^{23}$ particles of a substance. Fundamental unit of chemical quantity.

Flashcard 59: How many grams in 0.2 moles of H₂SO₄?

Answer: 19.62 grams. 0.2 mol × 98.08 g/mol = 19.62 g

Flashcard 60: Find the mass of 3 moles of HCl.

Answer: 109.5 grams. 3 mol × 36.5 g/mol = 109.5 g

Flashcard 61: What is the molar mass of H₃PO₄?

Answer: 97.99 g/mol. H = 1.01, P = 30.97, O = 16.00: $(3 \times 1.01) + 30.97 + (4 \times 16.00)$

Flashcard 62: What is molar mass?

Answer: The mass of one mole of a substance, in g/mol. Connects mass to amount of substance.

Flashcard 63: Find the molar mass of C₃H₈.

Answer: 44.10 g/mol. C = 12.01, H = 1.01: $(3 \times 12.01) + (8 \times 1.01)$

Flashcard 64: What is the molar mass of $MgCl_2$?

Answer: 95.21 g/mol. Mg = 24.31, Cl = 35.45: $24.31 + (2 \times 35.45)$

Flashcard 65: How is moles of a substance calculated from mass?

Answer: Moles = mass / molar mass. Divides mass by molar mass for conversion.

Flashcard 66: Calculate mass of 2 moles of H₂SO₄.

Answer: 196.16 grams. 2 mol × 98.08 g/mol = 196.16 g

Flashcard 67: What is molar mass?

Answer: The mass of one mole of a substance, in g/mol. Connects mass to amount of substance.

Flashcard 68: What is the molar mass of KCl?

Answer: 74.55 g/mol. K = 39.10, Cl = 35.45: $39.10 + 35.45$

Flashcard 69: Determine moles in 150 g of H₂O.

Answer: 8.33 moles. 150 g ÷ 18.02 g/mol = 8.33 mol

Flashcard 70: What is the molar mass of Al₂O₃?

Answer: 101.96 g/mol. Al = 26.98, O = 16.00: $(2 \times 26.98) + (3 \times 16.00)$

Flashcard 71: Convert 5 moles of Fe to grams.

Answer: 279.5 grams. 5 mol × 55.9 g/mol = 279.5 g

Flashcard 72: Calculate mass of 0.75 moles of KBr.

Answer: 89.25 grams. 0.75 mol × 119.0 g/mol = 89.25 g

Flashcard 73: Find the molar mass of C₃H₈.

Answer: 44.10 g/mol. C = 12.01, H = 1.01: $(3 \times 12.01) + (8 \times 1.01)$

Flashcard 74: Determine moles in 4.5 grams of H₂.

Answer: 2.23 moles. 4.5 g ÷ 2.02 g/mol = 2.23 mol

Flashcard 75: How is moles of a substance calculated from mass?

Answer: Moles = mass / molar mass. Divides mass by molar mass for conversion.

Flashcard 76: What is the formula for number of particles?

Answer: Particles = moles $\times$ Avogadro's number. Converts moles to individual particles.

Flashcard 77: What is the definition of a mole in chemistry?

Answer: A mole is $6.022 \times 10^{23}$ particles of a substance. Fundamental unit of chemical quantity.

Flashcard 78: What is the formula for number of particles?

Answer: Particles = moles $\times$ Avogadro's number. Converts moles to individual particles.

Flashcard 79: What is the molar mass of NH₃?

Answer: 17.03 g/mol. N = 14.01, H = 1.01: $14.01 + (3 \times 1.01)$

Flashcard 80: How many atoms are in 1 mole of carbon?

Answer: $6.022 \times 10^{23}$ atoms. One mole contains Avogadro's number of atoms.

Flashcard 81: How many moles are in 100 grams of NaOH?

Answer: 2.5 moles. 100 g ÷ 40.00 g/mol = 2.5 mol

Flashcard 82: How many moles are in 100 grams of NaOH?

Answer: 2.5 moles. 100 g ÷ 40.00 g/mol = 2.5 mol

Flashcard 83: What is the molar mass of $MgCl_2$?

Answer: 95.21 g/mol. $Mg = 24.31$, $Cl = 35.45$: $24.31 + (2 \times 35.45)$

Flashcard 84: How many grams are in 0.5 moles of NaCl?

Answer: 29.22 grams. 0.5 mol × 58.44 g/mol = 29.22 g

Flashcard 85: What is the molar mass of CH₄?

Answer: 16.04 g/mol. C = 12.01, H = 1.01: $12.01 + (4 \times 1.01)$

Flashcard 86: Find the mass of 3 moles of HCl.

Answer: 109.5 grams. 3 mol × 36.5 g/mol = 109.5 g

Flashcard 87: How many moles are in 100 grams of NaOH?

Answer: 2.5 moles. 100 g ÷ 40.00 g/mol = 2.5 mol

Flashcard 88: Calculate number of molecules in 2 moles of CO₂.

Answer: $1.204 \times 10^{24}$ molecules. 2 mol × $6.022 \times 10^{23}$ = $1.204 \times 10^{24}$

Flashcard 89: Calculate moles from 200 g of CaCO₃.

Answer: 2 moles. 200 g ÷ 100.09 g/mol = 2.00 mol

Flashcard 90: What is the definition of a mole in chemistry?

Answer: A mole is $6.022 \times 10^{23}$ particles of a substance. Fundamental unit of chemical quantity.

Flashcard 91: What is the molar mass of KCl?

Answer: 74.55 g/mol. K = 39.10, Cl = 35.45: $39.10 + 35.45$

Flashcard 92: What is the molar mass of Fe₂O₃?

Answer: 159.69 g/mol. Fe = 55.85, O = 16.00: $(2 \times 55.85) + (3 \times 16.00)$

Flashcard 93: Find the mass of 3 moles of HCl.

Answer: 109.5 grams. 3 mol × 36.5 g/mol = 109.5 g

Flashcard 94: How many moles are in 18 grams of water?

Answer: 1 mole. 18 g ÷ 18.02 g/mol = 1 mol

Flashcard 95: What is the molar mass of C₆H₁₂O₆?

Answer: 180.18 g/mol. Glucose: $(6 \times 12.01) + (12 \times 1.01) + (6 \times 16.00)$

Flashcard 96: State Avogadro's number.

Answer: $6.022 \times 10^{23}$. The number of particles in one mole.

Flashcard 97: What is the molar mass of KCl?

Answer: 74.55 g/mol. K = 39.10, Cl = 35.45: $39.10 + 35.45$

Flashcard 98: What is the molar mass of MgCl₂?

Answer: 95.21 g/mol. Mg = 24.31, Cl = 35.45: $24.31 + (2 \times 35.45)$