List at least two chemical reactions that resulted in a yellow, orange, or red precipitate. For these reactions list the possible chemical name of the precipitate. What do these reactions (and the others similar to them) have in common? List at least two chemical reactions that resulted in a white precipitate. For these reactions list the possible chemical name of the precipitate. What do these reactions (and the others with white precipitates) have in common?
Of all the reactions you performed, how many resulted in a precipitate and how many did not? Make a general statement about the interaction of aqueous ionic compounds, using the term double-displacement reaction.
Safety in the lab has to be a priority at all times when doing an investigation. Describe how you demonstrated good safety practices by using goggles during the lab. Why was it important for you to wear goggles during the lab?

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year

a electronegativity decreases beacuse the size of nucleus is bigger.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.

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