What is percent of c in co2 (c=12.01 amu, o=16.00 amu)

27.29 % of CO2 is carbon.

Explanation:

Not every element has the same molar mass, so they are present in a different %

Step 1: Calculating the molar mass of CO2

⇒CO2 has 1 carbon atom and 2 oxygen atoms

⇒ Molar mass of C= 12.01g/mole

⇒Molar mass of O = 16g/mole

⇒Molar mass of CO2 = 12.01 + 2*16g/mole = 44.01g /mole

Step 2: find the percentage of Carbon

To find the percentage of carbon, we will calculate the ratio Molar mass Carbon / Molar mass CO2

⇒ (12.01 / 44.01) * 100 % = 0.2729 * 100 % = 27.29 %

27.29 % of CO2 is carbon. This means that 72.71 % of CO2 is oxygen ( 100 - 27.29 = 72.71)

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