Chapter 3 Flashcards
(21 cards)
What is Stoichiometry?
Stoichiometry is the branch of chemistry that deals with the calculation of quantities of reactants and products in chemical reactions. It involves using balanced chemical equations to determine the amounts of substances involved in a reaction.
1 mole contains how many entities or particles?
6.022 x 10^23
6.022 x 10^23 or one mole is also referred to as what?
Avogadro’s Number
What is molar mass (MM) and what is the unit of molar mass?
Molar mass (MM) is the mass of one mole of a substance. The unit of molar mass is g/mol.
What is the Molar Mass of O2?
32.00g/mol
What is an Empirical Formula?
An Empirical Formula gives the ratio of atoms of each element in a compound.
What is a Molecular Formula?
A Molecular Formula gives the actual number of atoms of each element in a compound.
What is a Structural Formula?
A Structural Formula gives the way atoms of each element in a compound are linked together.
How do you find the Empirical Formula using percent composition?
Step to Find Empirical Formula By Percent Composition
(i) Find the mass (g) of each element in the compound
(ii) Convert mass of each element to moles
(iii) Divide by the smallest mole to obtain the mole ratio (round up or multiply to obtain whole numbers) – this gives the empirical formula
How do you convert grams (g) of a substance to moles (mol) of a substance?
Moles= Mass in grams/MolarMass(g/mol)
How do you find the Molecular formula using the empirical formula?
Molecular Formula = Empirical Formula x Whole-number multiple
OR
Whole-number Multiple = molecular formula mass/empirical formula mass
Find the whole number multiple and multiply it by the empirical formula.
What is a limiting reagent (reactant)?
The reagent that will be used up first during a chemical reaction. Since it is used up first it “limits” the amount of products which form.
What is an excess reagent (reactant)?
Any reactant which is not the limiting reactant in a chemical reaction.
What is the formula for concentration?
What does amphoteric mean?
A substance is amphoteric if it can act as both an acid and a base depending on the situation. This refers to its ability to donate or accept protons (H⁺).
What does polar mean?
A molecule is polar if it has a distribution of charge that creates a dipole moment, meaning one part of the molecule is slightly negative (δ−) and another part is slightly positive (δ+).
What is the formula for diluting a solution?
Mi x Vi = Mf x Vf
Or
ci x Vi = cf x Vf
Where:
Mi = initial molarity
Mf = final molarity
Vi = initial volume
Vf = final volume
ci = initial concentration
cf = final concentration
What is the formula for finding the Molecular formula using the empirical formula?
Molecular Formula MM/Empirical Formula MM
Formula for finding number of moles?
n = mass(g)/MM
Formula for density?
Density = mass/volume
What is the speed of light?
3.00 x 10^8 m/s
