Physical properties are used to classify and compare substances. Physical properties can include density, thermal conductivity, electrical conductivity, solubility, magnetism, melting point, and boiling point. Which statement is correct about all of these physical properties? A. They involve a change in the identity of matter.
B. They involve the production of new substances.
C. They can be measured only after a change in identity.
D. They are independent of the amount of the sample present

idk

explanation:

la respuesta es si te gusta hacer lo que siempre haces cuando nunca ves a alguien en el espejo porque sabes que no siempre están ahí.

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