Question 1

How many atoms of ¹²C are in a 3.50 g sample of this particular isotope?

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Question 2

The atomic mass of aluminum is 26.982 u. How many aluminum atoms are in a 4.55 g sample of aluminum?

Accepted Answer

The correct answer is A because:1. Convert the mass of aluminum to grams: 4.55 g2. Convert the mass of aluminum to moles: 4.55 g / 26.982 g/mol = 0.1685 mol3. Convert the moles of aluminum to atoms: 0.1685 mol * 6.022 x 10^23 atoms/mol = 1.02 x 10^23 atoms

Question 3

The atomic mass of neon is 20.1797 u. What is the mass, in grams, of a neon sample which contains 1.00 × 10²⁰ neon atoms?

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Question 4

The atomic mass of magnesium is 24.3050 u. What is the mass, in grams, of a magnesium sample which contains 3.22 × 10²² magnesium atoms?

Accepted Answer

The correct answer is A.The mass of a magnesium sample which contains 3.22 × 10^22 magnesium atoms can be calculated using the following formula:mass = number of atoms × atomic massmass = 3.22 × 10^22 atoms × 24.3050 umass = 7.82 × 10^23 uConverting the mass from atomic mass units (u) to grams (g) using the conversion factor 1 u = 1.6605 × 10^-24 g, we get:mass = 7.82 × 10^23 u × 1.6605 × 10^-24 g/umass = 1.30 gTherefore, the mass of a magnesium sample which contains 3.22 × 10^22 magnesium atoms is 1.30 g.

Question 5

How many molecules of carbon dioxide are in 154.0 grams of carbon dioxide? Hint: Think about your pathway to solving. Can you convert directly from mass to molecules or is there an intermediate unit you should use?

Accepted Answer

First, convert the mass of CO2 to moles using its molar mass (44.01 g/mol). Then, use Avogadro's number (6.022 × 10^23 molecules/mol) to convert moles to molecules.

Question 6

How many formula units of sodium chloride are in 146 grams of sodium chloride? Hint: Think about your pathway to solving. Can you convert directly from mass to formula units or is there an intermediate unit you should use?

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Question 7

How many moles of carbon atoms are in 0.145 moles of the compound, C₃H₈?

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Question 8

How many moles of oxygen atoms are in 1.08 moles of Ca(NO₃)₂?

Accepted Answer

Each molecule of Ca(NO3)2 contains 6 oxygen atoms. Therefore, 1.08 moles of Ca(NO3)2 contain 1.08 x 6 = 6.48 moles of oxygen atoms.

Question 9

A sample of Ca₃(PO₄)₂ contains 3.51 moles of calcium ions. How many moles of Ca₃(PO₄)₂ are in that sample?

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Question 10

How many moles of carbon atoms are combined with 11.2 moles of hydrogen atoms in a sample of the compound, C₃H₈?

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Question 11

A sample of C₁₂H₂₂O₁₁ contains 0.4662 moles of carbon atoms. How many moles of hydrogen atoms are in the sample?

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Question 12

A sample of HOOCC₆H₄OH contains 0.6540 moles of hydrogen atoms. How many moles of carbon atoms are in the sample?

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Question 13

A sample of Ni(CO)₄, a toxic transition-metal complex, has 5.23 × 10²⁴ atoms of carbon. How many atoms of Ni does it contain?

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Question 14

How many sodium atoms are in 6.0 g of Na₃N?

Accepted Answer

First, calculate the molar mass of Na₃N: (3 × 23) + 14 = 83 g/mol. Then, find moles of Na₃N in 6.0 g: 6.0 g / 83 g/mol = 0.0723 mol. Since each formula unit of Na₃N contains 3 sodium atoms, multiply the moles of Na₃N by 3 and Avogadro's number (6.022 × 10²³) to find the number of sodium atoms: 0.0723 mol × 3 × 6.022 × 10²³ = 1.3 × 10²³ atoms.

Question 15

A sample of K₃Fe(CN)₆ contains 1.084 × 10²⁴ carbon atoms. How many potassium atoms are in the sample?

Accepted Answer

In K₃Fe(CN)₆, there are 6 carbon atoms per formula unit. Therefore, the number of formula units is 1.084 × 10²⁴ carbon atoms / 6 = 1.807 × 10²³ formula units. Since there are 3 potassium atoms per formula unit, the number of potassium atoms is 3 × 1.807 × 10²³ = 5.420 × 10²³ atoms.

Question 16

A sample of phosphorus trifluoride, PF₃, contains 1.400 moles of the substance. How many atoms are in the sample?

Accepted Answer

1 mole of PF3 contains 4 moles of atoms (1 P atom and 3 F atoms). So, 1.400 moles of PF3 contains 1.400 moles * 4 moles of atoms/mole = 5.6 moles of atoms. 5.6 moles of atoms * 6.022 × 10^23 atoms/mole = 3.372 × 10^24 atoms.

Question 17

A sample of arabinose, C₅H₁₀O₅, contains 0.6000 moles of the substance. How many carbon atoms are in the sample?

Accepted Answer

Each molecule of arabinose contains 5 carbon atoms. Therefore, 0.6000 moles of arabinose contain 0.6000 moles × 5 carbon atoms/molecule × 6.022 × 10^23 atoms/mole = 1.807 × 10^24 carbon atoms.

Question 18

Which contains the greatest number of carbon atoms?

Accepted Answer

0.250 moles of glucose (C6H12O6) contains 0.250 * 6 = 1.5 moles of carbon atoms, which is the greatest among the options.

Question 19

Which contains the greatest number of hydrogen atoms?

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Question 20

A sample of (N₂H₅)₂C₃H₄O₄ contains 1.084 × 10²⁴ carbon atoms. How many moles of hydrogen atoms are in the sample? Hint: You can't convert directly between atoms of carbon and moles of hydrogen, use an intermediary unit.

Accepted Answer

The compound (N₂H₅)₂C₃H₄O₄ contains 4 hydrogen atoms per formula unit. First, calculate the number of moles of carbon atoms using Avogadro's number (6.022 × 10²³ atoms/mol): 1.084 × 10²⁴ carbon atoms / 6.022 × 10²³ atoms/mol = 1.8 moles of carbon. Since there are 3 carbon atoms per formula unit, there are 1.8 / 3 = 0.6 moles of the compound. Each formula unit contains 10 hydrogen atoms, so there are 0.6 moles × 10 = 6 moles of hydrogen atoms. However, the correct calculation should consider the total hydrogen atoms in the compound, leading to 8.4 moles of hydrogen atoms.

Quiz 4: The Mole and Stoichiometry

How many atoms of ¹²C are in a 3.50 g sample of this particular isotope?

The atomic mass of aluminum is 26.982 u. How many aluminum atoms are in a 4.55 g sample of aluminum?

The atomic mass of neon is 20.1797 u. What is the mass, in grams, of a neon sample which contains 1.00 × 10²⁰ neon atoms?

The atomic mass of magnesium is 24.3050 u. What is the mass, in grams, of a magnesium sample which contains 3.22 × 10²² magnesium atoms?

How many molecules of carbon dioxide are in 154.0 grams of carbon dioxide? Hint: Think about your pathway to solving. Can you convert directly from mass to molecules or is there an intermediate unit you should use?

How many formula units of sodium chloride are in 146 grams of sodium chloride? Hint: Think about your pathway to solving. Can you convert directly from mass to formula units or is there an intermediate unit you should use?

How many moles of carbon atoms are in 0.145 moles of the compound, C₃H₈?

How many moles of oxygen atoms are in 1.08 moles of Ca(NO₃) ₂?

A sample of Ca₃(PO₄) ₂ contains 3.51 moles of calcium ions. How many moles of Ca₃(PO₄) ₂ are in that sample?

How many moles of carbon atoms are combined with 11.2 moles of hydrogen atoms in a sample of the compound, C₃H₈?

A sample of C₁₂H₂₂O₁₁ contains 0.4662 moles of carbon atoms. How many moles of hydrogen atoms are in the sample?

A sample of HOOCC₆H₄OH contains 0.6540 moles of hydrogen atoms. How many moles of carbon atoms are in the sample?

A sample of Ni(CO) ₄, a toxic transition-metal complex, has 5.23 × 10²⁴ atoms of carbon. How many atoms of Ni does it contain?

How many sodium atoms are in 6.0 g of Na₃N?

A sample of K₃Fe(CN) ₆ contains 1.084 × 10²⁴ carbon atoms. How many potassium atoms are in the sample?

A sample of phosphorus trifluoride, PF₃, contains 1.400 moles of the substance. How many atoms are in the sample?

A sample of arabinose, C₅H₁₀O₅, contains 0.6000 moles of the substance. How many carbon atoms are in the sample?

Which contains the greatest number of carbon atoms?

Which contains the greatest number of hydrogen atoms?

A sample of (N₂H₅) ₂C₃H₄O₄ contains 1.084 × 10²⁴ carbon atoms. How many moles of hydrogen atoms are in the sample? Hint: You can't convert directly between atoms of carbon and moles of hydrogen, use an intermediary unit.

Quiz 4: The Mole and Stoichiometry

How many atoms of 12C are in a 3.50 g sample of this particular isotope?

The atomic mass of aluminum is 26.982 u. How many aluminum atoms are in a 4.55 g sample of aluminum?

The atomic mass of neon is 20.1797 u. What is the mass, in grams, of a neon sample which contains 1.00 × 1020 neon atoms?

The atomic mass of magnesium is 24.3050 u. What is the mass, in grams, of a magnesium sample which contains 3.22 × 1022 magnesium atoms?

How many molecules of carbon dioxide are in 154.0 grams of carbon dioxide? Hint: Think about your pathway to solving. Can you convert directly from mass to molecules or is there an intermediate unit you should use?

How many formula units of sodium chloride are in 146 grams of sodium chloride? Hint: Think about your pathway to solving. Can you convert directly from mass to formula units or is there an intermediate unit you should use?

How many moles of carbon atoms are in 0.145 moles of the compound, C3H8?

How many moles of oxygen atoms are in 1.08 moles of Ca(NO3) 2?

A sample of Ca3(PO4) 2 contains 3.51 moles of calcium ions. How many moles of Ca3(PO4) 2 are in that sample?

How many moles of carbon atoms are combined with 11.2 moles of hydrogen atoms in a sample of the compound, C3H8?

A sample of C12H22O11 contains 0.4662 moles of carbon atoms. How many moles of hydrogen atoms are in the sample?

A sample of HOOCC6H4OH contains 0.6540 moles of hydrogen atoms. How many moles of carbon atoms are in the sample?

A sample of Ni(CO) 4, a toxic transition-metal complex, has 5.23 × 1024 atoms of carbon. How many atoms of Ni does it contain?

How many sodium atoms are in 6.0 g of Na3N?

A sample of K3Fe(CN) 6 contains 1.084 × 1024 carbon atoms. How many potassium atoms are in the sample?

A sample of phosphorus trifluoride, PF3, contains 1.400 moles of the substance. How many atoms are in the sample?

A sample of arabinose, C5H10O5, contains 0.6000 moles of the substance. How many carbon atoms are in the sample?

Which contains the greatest number of carbon atoms?

Which contains the greatest number of hydrogen atoms?

A sample of (N2H5) 2C3H4O4 contains 1.084 × 1024 carbon atoms. How many moles of hydrogen atoms are in the sample? Hint: You can't convert directly between atoms of carbon and moles of hydrogen, use an intermediary unit.

How many atoms of ¹²C are in a 3.50 g sample of this particular isotope?

The atomic mass of neon is 20.1797 u. What is the mass, in grams, of a neon sample which contains 1.00 × 10²⁰ neon atoms?

The atomic mass of magnesium is 24.3050 u. What is the mass, in grams, of a magnesium sample which contains 3.22 × 10²² magnesium atoms?

How many moles of carbon atoms are in 0.145 moles of the compound, C₃H₈?

How many moles of oxygen atoms are in 1.08 moles of Ca(NO₃) ₂?

A sample of Ca₃(PO₄) ₂ contains 3.51 moles of calcium ions. How many moles of Ca₃(PO₄) ₂ are in that sample?

How many moles of carbon atoms are combined with 11.2 moles of hydrogen atoms in a sample of the compound, C₃H₈?

A sample of C₁₂H₂₂O₁₁ contains 0.4662 moles of carbon atoms. How many moles of hydrogen atoms are in the sample?

A sample of HOOCC₆H₄OH contains 0.6540 moles of hydrogen atoms. How many moles of carbon atoms are in the sample?

A sample of Ni(CO) ₄, a toxic transition-metal complex, has 5.23 × 10²⁴ atoms of carbon. How many atoms of Ni does it contain?

How many sodium atoms are in 6.0 g of Na₃N?

A sample of K₃Fe(CN) ₆ contains 1.084 × 10²⁴ carbon atoms. How many potassium atoms are in the sample?

A sample of phosphorus trifluoride, PF₃, contains 1.400 moles of the substance. How many atoms are in the sample?

A sample of arabinose, C₅H₁₀O₅, contains 0.6000 moles of the substance. How many carbon atoms are in the sample?

A sample of (N₂H₅) ₂C₃H₄O₄ contains 1.084 × 10²⁴ carbon atoms. How many moles of hydrogen atoms are in the sample? Hint: You can't convert directly between atoms of carbon and moles of hydrogen, use an intermediary unit.