Answer:
Explanation: A chemical change is a reaction in which chemical composition of the substance changes. Some bonds are broken and some new bonds are formed.
The reactants are written in terms of their chemical formula on the left hand side and the products are written in terms of their chemical formula on right hand side with a arrow in between. The chemical symbols are followed by their physical states such as (l) for liquid, (s) for solid, (g) for gas and (aq) for aqueous.
Thus the only reaction producing a gas is
Answer:
The density of igneous rocks is related to its color. Darker colored rocks have a higher density because of its greater mineral and iron content. Its characteristics is opposite compared to lighter colored rocks that have less density because of lower mineral and iron content
More reactive than others
From the statement of Hess' law, the enthalpy of the reaction A---> C is +90 kJ
<h3>What is Hess' law?</h3>
Hess' law of constant heat summation states that for a multistep reaction, the standard enthalpy of reaction is always constant and is independent of the pathway or intermediate routes taken.
From Hess' law, the enthalpy change for the reaction A ----> C is calculated as follows:
A---> C = A ---> B + B ---> C
ΔH of A---> C = 30 kJ + 60 kJ
ΔH = 90 kJ
Therefore, the enthalpy of the reaction A---> C is +90 kJ
The above reaction A---> C can be shown in the enthalpy diagram below:
A -------------------> C (ΔH = +90 kJ)
\ /
\ / (ΔH = +60 kJ)
(ΔH = +30 J) \ /
> B
Learn more about enthalpy and Hess law at: brainly.com/question/9328637
