The density of aluminium is 2.7 g/cm3. Find the mass in grams of a bar of aluminum measuring 2.7 cm by 1.2 cm by 14.3 cm.

125.0964g

Explanation:

Density = mass/volume

Density = 2.7 gcm-3

Volume=2.7*1.2*14.3=46.332

Mass=?

Mass= density* volume

= 2.7× 46.332=125.0964g

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