The answer is C because you must do all the other things first to get to the that’s part hope that helps
Taking into account the definition of density, assuming all other conditions remain the same, increasing mass will cause an object's density to increase.
Density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space. That is, density is a quantity referred to the amount of mass contained in a given volume.
Density is an intensive property since it does not vary with the amount of substance.
Since density is the relationship between the mass and the volume of a substance, its calculation is defined as the quotient between the mass of a body and the volume it occupies:

In the previous expression it can be observed that the density is inversely proportional to the volume: the smaller the volume occupied by a certain mass, the greater the density.
On the other hand, density is directly proportional to mass: the greater the mass, the greater the density.
Finally, assuming all other conditions remain the same, increasing mass will cause an object's density to increase.
Learn more about density:
<span>So when the chemist combines Ethane (CH3CH3) and Chlorine (Cl2) with the intention of producing Chloroethane (CH3CH2Cl), the other product that's formed in this reaction is 1,2-dichloroethane (ClCH2CH2Cl) also called as Ethylene dichloride with molecular weight of 98.954 g/mol. This is a colorless oily flammable substance that weighs heaver when vaporized.</span>
The change in internal energy of the combustion of biphenyl in Kj is calculated as follows
=heat capacity of bomb calorimeter x delta T where delta T is change in temperature
delta T = 29.4 -25.8= 3.6 c
= 5.86 kj/c x 3.6 c = 21.096 kj