Answer:
The enthalpy change of the reaction comes out to be -890 Kj Explanation:To calculate the enthalpy of the reaction divided in multiple steps, we use Hess's law. This law states that the heat absorbed or evolved in a given chemical equation remains same whether the process occurs in one step or several steps.To apply this law, the enthalpy of the chemical equation is treated as ordinary algebraic expression and it can be added or subtracted to form the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes that occur during intermediate reactions.
Explanation:
My guess is A because leaves absorb sunlight for energy but idk
Answer:
The reactivity of metal is determined by the reactivity series. ... The metal which easily displaced aluminium will lie above in the series but that same element cannot displace sodium, so it will lie below in the series. Hence, from the series, we conclude that the unknown metal could be calcium or magnesium.
Explanation:
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Drill cores from the ocean floor were dated and found to be very young compared to the age of the earth. This means the crust had to be formed recently, which can be explained by creation of crust at a spreading center.