A company that is concerned about the environment wants to encourage the use of their fuel cell cars, so they are putting together information to help sell the cars. They want to be sure their material is accurate. Which piece of information is true about fuel cell cars? Fuel cell cars are cheaper to buy.
Fuel cell cars reduce use of non-renewable fossil fuels
Fuel cell cars are more powerful than gasoline-powered vehicles.
Fuel cell cars allow for the safe storage of hydrogen gas at filling stations.

clouds form

solid ice forms on leaves.

water droplets form on grass.

i'm wiling to try and you : )

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