Module 5 - Solutions and Molarity Flashcards
week 5 (16 cards)
What is atomic weight?
The average mass of atoms in an element, taking isotopes into account.
What unit is atomic weight measured in?
Atomic mass unit (amu).
How do you calculate atomic weight from isotopes?
Atomic weight = (% × isotope 1 mass in amu) + (% × isotope 2 mass in amu) + …
What is formula mass?
The sum of all atomic weights in a chemical formula (molecular or ionic).
What is molecular mass?
The sum of all atomic weights in a molecule’s molecular formula.
How do you calculate mass from moles and molar mass?
mass (g) = moles × molar mass (g/mol).
Why is formula mass used for ionic compounds?
Because they consist of formula units, not discrete molecules.
Why is molecular mass used for covalent compounds?
Because they consist of actual molecules.
What is a solution?
A homogeneous mixture with uniform composition at the molecular or atomic level.
In what phases can a solution exist?
Solutions can exist in any phase: solid, liquid, or gas.
What is the formula for molarity?
M = moles of solute / liters of solution.
What is the formula for final molarity in a dilution?
Mf = (Mi × Li) / Lf.
What is the dilution formula?
C1V1 = C2V2.
How do you calculate moles of titrant?
Moles = Molarity × Volume.
What must you determine from a balanced chemical equation in titration?
The molar ratio of acid to base.
How do you find the concentration of an unknown analyte?
Divide moles of analyte by its volume.
