Mole Concept quiz #1 Flashcards
Mole Concept quiz #1
You can tap to flip the card.
Control buttons has been changed to "navigation" mode.
1/40Skip to main content
Magnesium and iron are metallic elements. How does a mole of magnesium compare with a mole of iron?
A mole of magnesium contains the same number of atoms as a mole of iron (6.022×10^23 atoms), but their masses differ according to their molar masses. Which value gives the number of particles in 1 mol of a substance?
Avogadro's number, 6.022×10^23, gives the number of particles in 1 mole. How are a mole and a dozen similar?
Both are counting units; a dozen is 12 items, while a mole is 6.022×10^23 particles. What is the relationship between a mole and Avogadro’s number?
One mole contains exactly Avogadro's number (6.022×10^23) of particles. How many moles are in 23.4 g of CaCl2?
Moles = 23.4 g ÷ molar mass of CaCl2 (110.98 g/mol) ≈ 0.211 moles. How many particles are in one mole?
One mole contains 6.022×10^23 particles. Which is the number of carbon atoms in exactly 12 g of pure carbon-12?
6.022×10^23 carbon atoms. What is the number of moles present? (mol)
The number of moles is calculated by dividing the given mass by the molar mass of the substance. What is a mole in chemistry terms?
A mole is the amount of substance containing 6.022×10^23 particles, equal to the number of atoms in 12 g of carbon-12. How many moles of Cl are in one mole of CaCl2?
There are 2 moles of Cl atoms in 1 mole of CaCl2. Which proportionality applies to Avogadro’s law?
Volume is directly proportional to the number of moles at constant temperature and pressure. How many moles of HCl are there in 75.0 mL of 0.150 M HCl?
Moles = 0.075 L × 0.150 mol/L = 0.01125 mol. How many atoms are in one mole of carbon?
6.022×10^23 atoms. If you have a mole of carbon atoms, how many atoms do you have?
You have 6.022×10^23 carbon atoms. How many moles of water are in a given sample?
Divide the mass of water by its molar mass (18.02 g/mol) to find the number of moles. How many atoms are in a 24 g sample of carbon?
24 g ÷ 12.01 g/mol = 2 moles; 2 × 6.022×10^23 = 1.204×10^24 atoms. How many Mg ions are present in 3.00 moles of MgCl2?
3.00 moles of MgCl2 contain 3.00 moles of Mg^2+ ions. How many moles of K2SO4 are in 15.0 g of K2SO4?
Moles = 15.0 g ÷ 174.26 g/mol ≈ 0.0861 moles. How many things are in a mole?
A mole contains 6.022×10^23 things (particles). Avogadro's law states that at a given temperature and pressure, what is true?
Equal volumes of gases contain equal numbers of moles (particles). A mole is defined as the number of atoms in an exact mass of which isotope?
Carbon-12. Which of the following contains the most moles of atoms?
The sample with the greatest number of atoms per given mass or volume contains the most moles. How many atoms are in 1 mole?
6.022×10^23 atoms. How many molecules of water are in 18.01 g (one mole) of water?
6.022×10^23 molecules. One mole of particles of any substance contains how many particles?
6.022×10^23 particles. How many moles of KNO3 are in 500.0 mL of 2.0 M KNO3?
Moles = 0.500 L × 2.0 mol/L = 1.0 mol. What does a mole measure?
A mole measures the amount of substance, specifically 6.022×10^23 particles. If there are 12 × 10^23 oxygens in a sample of water, how many moles of oxygen atoms are present?
12 × 10^23 ÷ 6.022×10^23 ≈ 1.99 moles. Approximately how many atoms of carbon are present in a 120 gram sample of carbon?
120 g ÷ 12.01 g/mol = 9.99 mol; 9.99 × 6.022×10^23 ≈ 6.02×10^24 atoms. Approximately how many particles are in 2 moles?
2 × 6.022×10^23 = 1.204×10^24 particles. How many hydrogen atoms are in 2 moles of H2O?
Each H2O has 2 H atoms: 2 moles × 2 × 6.022×10^23 = 2.41×10^24 H atoms. How many atoms are in 1.50 moles of Hg?
1.50 × 6.022×10^23 = 9.03×10^23 atoms. What is the total number of moles of NaCl(s) needed to make 3.0 liters of a 2.0 M NaCl solution?
Moles = 3.0 L × 2.0 mol/L = 6.0 mol. Why is it useful to use moles to measure chemical quantities?
Moles allow chemists to count large numbers of particles and relate mass to number of particles. How many moles of iron (Fe) are in 279 g of iron?
279 g ÷ 55.85 g/mol ≈ 5.00 moles. How many carbon atoms are present in a mole of 12C?
6.022×10^23 carbon atoms. What is the mole ratio of H to N in the ammonia molecule?
3:1 (3 H atoms for every 1 N atom in NH3). Why is the mole an important unit to chemists?
It allows chemists to relate mass, number of particles, and volume in chemical reactions. Which value approximately represents the number of atoms in one mole of gold?
6.022×10^23 atoms. Why do we want to use the concept of moles?
To count and relate large numbers of atoms, molecules, or ions in chemical reactions.
01:25
