MOLES Flashcards
(38 cards)
What is the mole concept?
The mole concept is a way to express amounts of a chemical substance using the unit ‘mole’, which is defined as 6.022 x 10^23 particles.
What is Avogadro’s number?
Avogadro’s number is 6.022 x 10^23, representing the number of atoms, molecules, or particles in one mole of a substance.
True or False: One mole of any substance contains the same number of entities.
True.
What is the relationship between moles and mass?
The number of moles of a substance is equal to the mass of the substance (in grams) divided by its molar mass (in g/mol).
Fill in the blank: The molar mass of water (H2O) is _____ g/mol.
18.02
What does a balanced chemical equation represent?
A balanced chemical equation represents a chemical reaction where the number of atoms of each element is the same on both sides of the equation.
True or False: The law of conservation of matter states that matter can be created or destroyed in a chemical reaction.
False.
What is the law of conservation of matter?
The law of conservation of matter states that matter cannot be created or destroyed in a chemical reaction; it is only transformed.
How many moles are in 36 grams of water (H2O)?
2 moles.
What is the formula to calculate the number of moles?
Number of moles = mass (g) / molar mass (g/mol).
What is the molar mass of carbon dioxide (CO2)?
44.01 g/mol.
Fill in the blank: In a balanced equation, the coefficients represent the _____ of moles of each reactant and product.
ratio
What is the significance of balancing chemical equations?
Balancing chemical equations ensures that the law of conservation of matter is upheld, showing that the same number of atoms of each element is present before and after the reaction.
True or False: A balanced equation can have different numbers of atoms on each side.
False.
What is the molar mass of sodium chloride (NaCl)?
58.44 g/mol.
What does the coefficient ‘2’ in front of H2O in a balanced equation indicate?
It indicates that there are 2 moles of water molecules.
How many grams are in 3 moles of sodium (Na)?
69.72 grams.
What is the purpose of using Avogadro’s number in chemistry?
Avogadro’s number is used to convert between moles and number of particles, allowing chemists to quantify substances at the atomic or molecular level.
Fill in the blank: The total mass of reactants must equal the total mass of _____ in a chemical reaction.
products
What is the first step in balancing a chemical equation?
Identify the number of atoms of each element in the reactants and products.
True or False: The molar mass of an element is the same as its atomic mass.
True.
What is the molar volume of an ideal gas at STP?
22.4 liters.
How do you determine the number of molecules in a sample?
Multiply the number of moles by Avogadro’s number.
What are the units of molar mass?
grams per mole (g/mol).
