<span>Molds are created to achieve a
specific design of a material. These materials either came from a process of
having a higher or lower temperature. Therefore, the molder must have thermal
resistant properties. Low melting points means that the material to be shaped
came from a cooler process. Wood and metal have higher thermal conductivity and
therefore can easily be cooled. The wax can turn really hard and can be
unbreakable when present in colder materials due to the lipids present in it. Clay
however can become a mold because of its low melting point.</span>
Zero because there are so many electrons as protons.
Yes it is correctly balanced. :)
Answer:
1. The change in energy is 60KJ or 6.0 × 10^1 KJ
2. Endothermic reaction
Explanation:
The Enthalpy (ΔU) for the mixture is given as 215kJ and the workdone (W) on the mixture is - 155KJ. Hence, the change in the energy (ΔH) ofthe mixture is computed using the equation below:
ΔH = ΔU + w
Where,
ΔH= Change in energy
ΔU= Enthalpy change
W= workdone
Therefore ΔH is:
ΔH= 215 kJ + (-155Kj)
ΔH= 60 KJ
Therefore, the change in energy is 60KJ or 6.0 × 10^1 KJ
The value is positive so it is an endothermic reaction.
An endothermic reaction happens when the energy used to break the bonds in the reactants is higher than the energy given out when bonds are formed in the products. This means that the entire reaction takes in energy, hence there is a temperature decrease in the surroundings. Endothermic reactions cannot happen spontaneously. Work is usually done in order to get these reactions to occur. When endothermic reactions absorb energy, a temperature drop is measured by the reaction.
