C. Spacecraft are built to be airtight.
Answer:
ΔH =
Explanation:
In a calorimeter, when there is a complete combustion within the calorimeter, the heat given off in the combustion is used to raise the thermal energy of the water and the calorimeter.
The heat transfer is represented by
= 
where
= the internal heat gained by the whole calorimeter mass system, which is the water, as well as the calorimeter itself.
= the heat of combustion
Also, we know that the total heat change of the any system is
ΔH = ΔQ + ΔW
where
ΔH = the total heat absorbed by the system
ΔQ = the internal heat absorbed by the system which in this case is 
ΔW = work done on the system due to a change in volume. Since the volume of the calorimeter system does not change, then ΔW = 0
substituting into the heat change equation
ΔH =
+ 0
==> ΔH =
Answer:
Compound are defined as the containing two or more different element .
(1) Ionic compound and (2) Covalent compound.
Explanation:
Covalent compound :- covalent compound are the sharing of electrons two or more atom.
Covalent compound are physical that lower points and compared to ionic .
Covalent compound that contain bond are carbon monoxide (co), and methane .
Covalent compound are share the pair of electrons.
Covalent compound are bonding a hydrogen atoms electron.
Ionic compound a large electrostatic actions between atoms.
Ionic compound are higher melting points and covalent compound.
Ionic compound are bonding a nonmetal electron.
Ionic electron can be donate and received ionic bond.
Ionic compound bonding kl.