Performing Stoichiometry Calculations

Notes and Practice for ALMOST every possible

calculation

Masses to molesSteps: 1) Determine molar mass of given substance

2) Divide amount given in problem by the molar mass you calculated.1. How many moles does 80.0 grams of H2O represent?

2. How many moles does 45.0 grams of C6H12O6 represent?

3. How many moles does 22.0 grams of CO2 represent?

4. How many moles does 56.0 grams of N2 represent?

Moles to massSteps: 1) Calculate Molar Mass of given

substance. 2) Multiply given number of moles by

the molar mass you just calculated

1. What is the mass of 2.0 moles of LiOH ?

2. What is the mass of 5.0 moles of Ba(CN)2 ?

3. What is the mass of 3.5 moles of water?

4. What is the mass of 0.75 moles of CuSO4?

Moles to ParticlesStep 1) Multiply number of moles given by Avogadro's

number (6.02 x 1023)

1. How many atoms does 2.0 moles of He represent?

2. How many sodium ions are in 3.0 moles of NaCl?

3. How many molecules are in 0.25 moles of CH4?

4. How many total atoms are in 1.0 moles of H2O ?

Particles to MolesStep 1) Divide number of particles given by Avogadro's number

(6.02 x 1023)

1. How many moles of water does 6.02 x 1023 molecules represent?

2. Convert 3.01 x 1023 molecules of C2H6 to moles.

3. How many moles of glucose (C6H12O6) does 1.2 x 1024 molecules represent?

4. How many moles of CaCl2 does 2.41 x 1024 formula units represent?

Grams to MolesGrams of one substance to moles of another substance

Pre-Solution Steps: 1) Balance the equation 2) Calculate the molar mass of the given substance

3) Determine the molar ratio between the substance given and the substance asked to find. (The Coefficients in the balanced equation.)

Calculation Steps: 1) Determine the number of moles of the given substance by dividing the mass given by the molar mass of the given substance2) Convert moles of A to moles of B by multiplying the number of moles of substance A (given) by the molar ratio.

1) How many moles of NaCl will be produced if you start with 46 g of Na?

Na + Cl2 --> NaCl

2) How many moles of Na2SO4 are produced if you start with 126 g of NaOH?

NaOH + H2SO4 --> H2O + Na2SO4

Moles to GramsMoles of one substance to grams of another substance

Pre-Solution Steps: 1) Balance the equation 2) Calculate the molar mass of the requested substance

3) Determine the molar ratio between the substance given and the substance asked to find

Calculation Steps: 1) Determine the number of requested moles by multiplying the number of moles of substance A (given) by the molar ratio.2) Convert moles requested to grams by multiplying the number of requested moles but the molar mass you

1) How many grams of NaCl will be produced if you start with 4 moles of Na?

Na + Cl2 --> NaCl

2) How many grams of Na2SO4 are produced if you start with 12 moles of NaOH?

NaOH + H2SO4 --> H2O + Na2SO4

Grams to GramsGrams of one substance to grams of another substance

Pre-Solution Steps: 1) Balance the equation

2) Calculate the molar mass of the given substance

3) Calculate the molar mass of the requested substance

4) Determine the molar ratio between the substance given and the substance asked to find

Calculation Steps: 1 &2) Same as Grams to Moles

3) Multiply the number of moles requested by the molar mass of the requested substance.

1) How many grams of NaCl will be produced if you start with 46 g of Na?

Na + Cl2 --> NaCl

2) How many grams of Na2SO4 are produced if you start with 126 g of NaOH?

NaOH + H2SO4 --> H2O + Na2SO4

Grams to ParticlesGrams of one substance to Particles of another

Pre-Solution Steps: Same as Grams to Moles

Calculation Steps: 1 & 2) Same as Grams to Moles

3) Multiply the number of moles requested by Avogadro's number (6.02 x 1023).

1) How many molecules of NaCl will be produced if you start with 46 grams of Na?

Na + Cl2 --> NaCl

2) How many molecules of Na2SO4 are produced if you start with 126 grams of NaOH?

NaOH + H2SO4 --> H2O + Na2SO4

Particles to GramsParticles of one substance to grams of another

Pre-Solution Steps: Same as Moles to Grams

Calculation Steps: 1) Determine the number of moles of the given substance by dividing the particles given by Avogadro's number (6.02 x 1023)

2&3) Same as Moles to Grams

1) How many grams of NaCl will be produced if you start with 3.01 x 1023 atoms of Na?

Na + Cl2 --> NaCl

2) How many grams of Na2SO4 are produced if you start with 3.04 x 1024 molecules of NaOH?

NaOH + H2SO4 --> H2O + Na2SO4