Question

The percent yield of a chemical reaction is

Answer 1

Answer:

The correct choices are:

• using accurate measurements

• using pure chemicals

• performing the reaction under the most ideal conditions

Explanation:

The theoretical yield is the maximum amount of product that could be obtained by the chemical reaction, from a given amount  of reactants. You calculate the theoretical yield using the stoichiometry coefficients of the balanced chemical equation.

The percent yield is the ratio of the actual yield (the actual amount obtained) of a product to the theoretical yield for the same product, expressed as a percentage (i.e. multiplied by 100).

• percent yield = actual yield × 100 / theoretical yield

As the actual yield decrease (the numerator of the ratio), the percent yield decrease.

To increase the percent yield it is important:

• using accurate measurements

• using pure chemicals

• performing the reaction under the most ideal conditions

Using accurate measurements: if you do not add the correct amounts of each reactant, then the product obtained will not be what you can predict from the theoretical calculations and  you will be wasteing one or other reactant, without reaching the maximum yield possible.

Using pure chemicals: if the chemicals are not pure, the amount of actual reactants will be lower than they should be, leading to a lower actual yield.

Performing the reaction under the most ideal conditions: the actual rate of reactions depend on the conditions: temperature and pressure are the most commons. Since, temperature and pressure may change that rate of reactions, you should find and use the most ideal conditions to get the greatest actual yield.

Adding water, can just dilute the reactants and would decrease the rate of reaction, which would not be helpful to increase the yield.

Answer 2

Answer is using accurate measurements

using pure chemicals

performing the reaction under the most ideal conditions