Nowadays chemical compounds are presented in every field of life, medicine, cleaning, food …...but the chemical industry uses a lot of products, and sometimes very dangerous, for example, Sulphuric acid is so important that its level of production and consumption is an indication of development of a country. In this activity, you have to look for three importants chemicals for industry used as raw materials to manufacture other compounds and, apart from explaining what they are used for, investigate their chemical formula and calculate their molecular mass.

6.4 cm (max) - 25 cm (min)

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