Question

balance this reaction: c3h8o + o2 --> co2 + h2o. the coefficient on o2 is ______. question 2 1 pts a reaction has a theoretical yield of 7.845 g and an actual yield of 6.391g. what is the percent yield?

Explanation:

Step1: Balance the chemical equation

First, balance the carbon atoms. There are 3 carbon atoms in $C_3H_8O$, so we put a 3 in front of $CO_2$: $C_3H_8O + O_2
ightarrow3CO_2 + H_2O$. Then balance the hydrogen atoms. There are 8 hydrogen atoms in $C_3H_8O$, so we put a 4 in front of $H_2O$: $C_3H_8O+O_2
ightarrow3CO_2 + 4H_2O$. Now balance the oxygen atoms. On the right - hand side, we have $3\times2 + 4\times1=10$ oxygen atoms. Since there is 1 oxygen atom in $C_3H_8O$, the number of oxygen atoms from $O_2$ should be $10 - 1=9$. So we put a $\frac{9}{2}$ in front of $O_2$: $C_3H_8O+\frac{9}{2}O_2
ightarrow3CO_2 + 4H_2O$. Multiply through by 2 to get whole - number coefficients: $2C_3H_8O + 9O_2
ightarrow6CO_2+8H_2O$. The coefficient of $O_2$ is 9.

Step2: Calculate the percent yield

The formula for percent yield is $\text{Percent Yield}=\frac{\text{Actual Yield}}{\text{Theoretical Yield}}\times100\%$. Given that the theoretical yield is $7.845$ g and the actual yield is $6.391$ g. Substitute the values into the formula: $\text{Percent Yield}=\frac{6.391}{7.845}\times100\%$. Calculate $\frac{6.391}{7.845}\approx0.8147$, and $0.8147\times100\% = 81.47\%$.

Answer:

Question 1: 9
Question 2: 81.47%