Element Y has two natural isotopes Y-63 (62.940 amu) and Y-65 (64.928 amu). Calculate the atomic mass of element Y, given the ab
1 answer:
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Answer:
3.816 × 10⁻³ M
Explanation:
<em>A stock solution of Cu²⁺(aq) was prepared by placing 0.8875 g of solid Cu(NO₃)₂∙2.5H₂O in a 100.0-mL volumetric flask and diluting to the mark with water. What is the concentration (in M) of Cu²⁺(aq)in the stock solution?</em>
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We can establish the following relations:
- The molar mass of Cu(NO₃)₂∙2.5H₂O is 232.59 g/mol.
- 1 mole of Cu(NO₃)₂∙2.5H₂O contains 1 mole of Cu²⁺.
The moles of Cu²⁺ in 0.8875 g of Cu(NO₃)₂∙2.5H₂O are:
The molarity of Cu²⁺ is:
<u>Answer:</u> The for the reaction is 72 kJ.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction follows:
The intermediate balanced chemical reaction are:
(1)
(2)
( × 2)
(3)
( × 2)
The expression for enthalpy of the reaction follows:
Putting values in above equation, we get:
Hence, the for the reaction is 72 kJ.