A solution containing 41.8 g of nitrate, sulfate, and sodium carbonate was added with 92 cm3 of sulfuric acid solution (w=10%, p=1.065 g / cm3). In this stood out of 2.24 dm3 (n) of gas. Subsequent addition of barium chloride to the resulting solution resulted in 46.6 g of precipitation. Determine the mass fraction of salts in the initial mixture, taking into account that sodium sulfate is not formed.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

the answer is option a.

what are the statements

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