Stoichiometry

Question 1

Mole Calculations

Answer 1

Numberofmoles=Mass(ingrams) / Molarmass(ing/mol)

Moles = Number of Particles / 6.02 x 10²³ (Avogadro’s constant)

Number of ions = Ions * moles * 6.02 x 10²³

Question 2

Volume of Gas Calculation (at room temperature and pressure, RTP)

Answer 2

Volume(indm³)= Numberofmoles × 24 Volume(indm³)

Question 3

Concentration Calculation

Answer 3

Concentration(mols/dm³) = Numberofmoles (mols) / Volume(indm³)

Question 4

Percentage Yield & Purity Calculations

Answer 4

• PercentageYield= ( Actualyield / Theoreticalyield )× 100%
• Percentage Purity= ( Mass Pure / Mass Impure ) x 100%

Question 5

Percentage Composition Calculation for a compound and for an element in compound

Answer 5

• For an element in a compound:

Percentagecompositionof
element= ( Massofelement / Totalmassofcompound ) × 100%

• For a compound:

Percentagecompositionofcompound = ( Massofcomponent / Molarmassofcompound ) × 100%

Question 6

Unit Conversions

g -> mg

kg -> g

L -> ml

dm³ -> ml

cm³ -> ml

mol/dm³ -> g/dm³

Answer 6

Mass Conversions:
1 gram (g) = 1000 milligrams (mg)

1 kilogram (kg) = 1000 grams (g)

Volume Conversions:
1 liter (L) = 1000 milliliters (mL)

1 decimeter cubed (dm³) = 1000 milliliters (mL)

1 cubic centimeter (cm³) = 1 milliliter (mL)

Mole Conversions:
Mol/dm³ → g/dm³

Multiply mol/dm³ by the molar mass to get the concentration in g/dm³.