Are you ready to take this lesson's quiz? These questions will help you find out. Make sure you understand why each correct answer is correct—if you don't, review that part of the lesson.
Which of these describes a mole?
- the number of particles in 1 g of an element or compound
- a quantity of particles equal to Avogadro's number: 6.022 \( \times \) 1023
- the number of atoms in any sample of matter
- the mass of 6.022 \( \times \) 1023 representative particles of a substance
The number of particles in 1 g of a substance will vary depending on the type of particle.
One mole of a substance contains a number of representative particles equal to a defined quantity called Avogadro's number, which is equal to 6.022 \( \times \) 1023.
One mole is the number of representative particles equal to Avogadro's number, or 6.022 \( \times \) 1023. A representative particle can be an atom, molecule, or formula unit of an ionic compound.
The mass of 1 mol, or 6.022 \( \times \) 1023 particles, of a substance is the molar mass.
How many atoms are in 2.0 moles of xenon (Xe) gas?
- 1.2 \( \times \) 1024 atoms
- 3.3 \( \times \) 10-24 atoms
- 2.0 \( \times \) 1023 atoms
- 6.022 \( \times \) 1023 atoms
2.0 mol \( \times \frac{6.022 \times 10^{23} \text{ atoms}}{1 \text{ mol}} \)
Be sure to use the conversion factor, \( \frac{6.022 \times 10^{23} \text{ atoms}}{1 \text{ mol}} \), when converting from moles to atoms.
The number of atoms in 1 mole is equal to 6.022 \( \times \) 1023. The conversion factor, \( \frac{6.022 \times 10^{23} \text{ atoms}}{1 \text{ mol}} \), is used to convert from moles to atoms.
There are 6.022 \( \times \) 1023 atoms in one mole. Multiply the number of moles by the conversion factor \( \frac{6.022 \times 10^{23} \text{ atoms}}{1 \text{ mol}} \) to convert from moles to atoms.
How many moles of water are present in a sample containing 3.9 \( \times \) 1025 molecules of H2O?
- 65 moles
- 2.35 \( \times \) 1049 moles
- 3.9 \( \times \) 1025 moles
- 6.022 \( \times \) 1023 moles
3.9 \( \times \) 1025 molecules \( \times \frac{1 \text{ mol } }{6.022 \times 10^{23} \text{ molecules}} \)
Be sure to use the conversion factor \( \frac{1 \text{ mol } }{6.022 \times 10^{23} \text{ molecules}} \) when converting from molecules to moles.
The number of molecules in 1 mole is 6.022 \( \times \) 1023. Use the conversion factor \( \frac{1 \text{ mol } }{6.022 \times 10^{23} \text{ molecules}} \) when converting from molecules to moles.
There are 6.022 \( \times \) 1023 molecules in one mole. Multiply the number of molecules by the conversion factor \( \frac{1 \text{ mol } }{6.022 \times 10^{23} \text{ molecules}} \) to convert from molecules to moles.
Which of the following molar masses is correct?
- molar mass of NH3 = 15.02 \( \frac{\text{g}}{\text{mol}} \)
- molar mass of Ni = 14.01 \( \frac{\text{g}}{\text{mol}} \)
- molar mass of C6H12O6 = 174.12 \( \frac{\text{g}}{\text{mol}} \)
- molar mass of Cu3(PO4)2 = 380.59 \( \frac{\text{g}}{\text{mol}} \)
N (14.01 g) \( \times \) 1 + H (1.01) \( \times \) 3 = 17.02 \( \frac{\text{g}}{\text{mol}} \)
The molar mass of Ni is the same value as its atomic mass, 58.69, in grams.
C (12.01 g) \( \times \) 6 + H (1.01 g) \( \times \) 12 + O (16.00) \( \times \) 6 = 180.18 \( \frac{\text{g}}{\text{mol}} \)
Cu (63.55 g) \( \times \) 3 + P (30.97 g) \( \times \) 2 + O (16.00 g) \( \times \) 8 = 380.59 \( \frac{\text{g}}{\text{mol}} \)
How many moles of He are in a sample with a mass of 4.96 g?
- 1.24 mol
- 19.84 mol
- 3.0 \( \times \) 1024 mol
- 8.96 mol
4.96 g \( \times \frac{1 \text{ mol}}{4.00\ g} \)
To convert from mass of He to moles of He, multiply the mass by the conversion factor\( \frac{1 \text{ mol}}{4.00\ g} \) , which is the ratio of moles of He to its molar mass.
To convert from mass of He to moles of He, multiply the mass by the conversion factor \( \frac{1 \text{ mol}}{4.00\ g} \) , which is the ratio of moles of He to its molar mass.
Multiply the mass of the He sample by the conversion factor \( \frac{1 \text{ mol}}{4.00\ g} \) to convert from mass to moles.
Summary
Questions answered correctly:
Questions answered incorrectly:
