A student reacts 5.0 g of sodium with 10.0 g of chlorine and collect 5.24 g of sodium chloride. What is the percent yield of this combination reaction

The percent yield of this combination reaction is 41.3 %

Explanation : Given,

Mass of = 5.0 g

Mass of = 10.0 g

Molar mass of = 23 g/mol

Molar mass of = 71 g/mol

First we have to calculate the moles of and .

and,

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation will be:

From the balanced reaction we conclude that

As, 2 mole of react with 1 mole of

So, 0.217 moles of react with moles of

From this we conclude that, is an excess reagent because the given moles are greater than the required moles and is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of

From the reaction, we conclude that

As, 2 mole of react to give 2 mole of

So, 0.217 mole of react to give 0.217 mole of

Now we have to calculate the mass of

Molar mass of = 58.5 g/mole

Now we have to calculate the percent yield of this reaction.

Percent yield =

Actual yield = 5.24 g

Theoretical yield = 12.7 g

Percent yield =

Percent yield = 41.3 %

Therefore, the percent yield of this combination reaction is 41.3 %

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol