Chemical Percent Yield

When reacting Na with Cl₂, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percent yield?

• 90.4%

• 104%

• 96.15%

• 1.04%

Answer explanation

To calculate percent yield, use the formula: (actual yield / theoretical yield) x 100. Here, (12.5 g / 13 g) x 100 = 96.15%. Thus, the correct answer is 96.15%.

Tags

NGSS.HS-PS1-7

Theoretical yield = 73g
Actual yield = 62g
Calculate the percent yield.

• 1.16%

• 116%

• 85%

• 76%

Answer explanation

Percent yield is calculated using the formula: (Actual yield / Theoretical yield) x 100. Here, (62g / 73g) x 100 = 84.93%, which rounds to 85%. Thus, the correct answer is 85%.

Tags

NGSS.HS-PS1-7

A chemical reaction was carried out where a yield of 73g was expected, but a yield of 62g was obtained. Calculate the percent yield.

• 85%

• 118%

• 84.9%

• 11%

Answer explanation

Percent yield is calculated using the formula: (actual yield / expected yield) x 100. Here, (62g / 73g) x 100 = 84.93%, which rounds to 85%. Thus, the correct answer is 85%.

Tags

NGSS.HS-PS1-7

1. What is a limiting reagent?

• any reactant used up first in a reaction.

• any reactant left over at the end of a reaction.

• the maximum amount of product formed from a given amount of reactant.

• the purity of the reactant.

Answer explanation

A limiting reagent is the reactant that is completely consumed first in a chemical reaction, determining the maximum amount of product that can be formed. Thus, the correct choice is 'any reactant used up first in a reaction.'

Tags

NGSS.HS-PS1-7

7. The amount of product that actually forms when a chemical reaction is carried out in a laboratory is called the _________ yield.

• actual

• theoretical

• percent

Answer explanation

The correct answer is 'actual' yield, which refers to the amount of product that is actually produced in a reaction, as opposed to 'theoretical' yield, which is the maximum possible amount based on stoichiometry.

Tags

NGSS.HS-PS1-7

What is the molar mass of PbSO₄?

• 303.262 g/mol

• 255.262 g/mol

• 163.872 g/mol

• 372.262 g/mol

Answer explanation

To find the molar mass of PbSO4, sum the atomic masses: Pb (207.2 g/mol) + S (32.07 g/mol) + 4 x O (16.00 g/mol) = 303.26 g/mol. Thus, the correct answer is 303.262 g/mol.

What is Percent yield?

• the percent of Carbon in a substance

• the percent ratio of actual yield to the theoretical yield

• the percent ratio of reacted and unreacted substances

• 6.022 x 10^23

Answer explanation

Percent yield is defined as the percent ratio of actual yield to the theoretical yield. This measures the efficiency of a reaction, indicating how much product was obtained compared to what was expected.

Tags

NGSS.HS-PS1-7

Mole ratios are obtained from the

• balanced chemical equation

• periodic table

• molar mass

Answer explanation

Mole ratios are derived from the coefficients in a balanced chemical equation, which indicate the proportion of reactants and products involved in the reaction. Thus, the correct answer is the balanced chemical equation.

Reactant and products might adhere to containers causing actual yield to be less than theoretical yield.

• true

• false

Answer explanation

True. Reactants and products can stick to container surfaces, leading to a loss of material. This results in the actual yield being lower than the theoretical yield, confirming the statement.

Tags

112.43.c.9.C

Competing reactions might occur forming other products causing your actual yield to be less than your theoretical yield.

• true

• false

Answer explanation

True. Competing reactions can lead to the formation of unintended products, which reduces the amount of the desired product obtained, resulting in an actual yield that is less than the theoretical yield.

Tags

112.43.c.9.C