Yield (Chemistry)

Key Stage 4

Meaning

Yield is the mass of product in a chemical reaction.

About Yield

The theoretical yield of product form a chemical reaction can be calculated using the balanced symbol equation and the relative formula masses of all the molecules involved.

The experimental yield from a chemical reaction is often not as large as the theoretical yield because not all of the reactants will react. This experimental yield is often expressed as a percentage of the theoretical yield and is known as the Percentage Yield.

Examples

Calculate the yield of Magnesium Oxide given 48g of Magnesium and excess Oxygen. |style="height:20px; width:200px; text-align:center;" | Find the yield of Carbon Dioxide when 32g of Methane reacts with excess Oxygen.	Find the yield of Sodium Chloride when 80g of Sodium Hydroxide react with 73g of Hydrochloric Acid.
Write the Balanced Symbol Equation 2Mg + O2 → 2MgO	Write the Balanced Symbol Equation CH4 + 2O2 → 2H2O + CO2	Write the Balanced Symbol Equation NaOH + HCl → NaCl + H2O
Find the Relative Formula Mass of the reactants and products. Mr of Mg = 24g Mr of 2Mg = 48g Mr of O2 = 16x2 Mr of O2 = 32g Mr of MgO = 24+16 Mr of MgO = 40g	Find the Relative Formula Mass of the reactants and products. Mr of CH4 = 12+1x4 Mr of CH4 = 16g Mr of O2 = 16x2 Mr of O2 = 32g Mr of 2O2 = 64g Mr of CO2 = 12+16x2 Mr of CO2 = 44g Mr of H2O = 1x2+16 Mr of H2O = 18 Mr of 2H2O = 36g	Find the Relative Formula Mass of the reactants and products. Mr of NaOH = 40g Mr of HCl = 36.5g Mr of NaCl = 23+35.5 Mr of NaCl = 58.5g Mr of H2O = 1x2+16 Mr of H2O = 18
State the ratio of moles of each chemical needed. 2 moles of Mg are needed for every 1 mole of O2	State the ratio of moles of each chemical needed. 1 mole of CH4 is needed for every 2 moles of O2	State the ratio of moles of each chemical needed. 1 mole of HCl are needed for every 1 mole of NaOH
Find the number of moles supplied of the known mass. No. Moles = \(\frac{Mass}{M_r}\) No. Moles = \(\frac{48}{24}\) No. Moles = 2 Mole Therefore 1 mole of O2 is needed. 1 mole of O2 = 32g	Find the number of moles supplied of the known mass. No. Moles = \(\frac{Mass}{M_r}\) No. Moles = \(\frac{32}{16}\) No. Moles = 2 Mole Therefore 4 moles of O2 are needed. 4 moles of O2 = 128g	Find the number of moles supplied of the known mass. No. Moles = \(\frac{Mass}{M_r}\) No. Moles = \(\frac{20}{40}\) No. Moles = 0.5 Mole Therefore 0.5 mole of HCl is needed. 0.5 mole of HCl = 18.25g