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Answer:
b
Explanation:
The reaction that is not a displacement reaction from all the options is
In a displacement reaction, a part of one of the reactants is replaced by another reactant. In single displacement reactions, one of the reactants completely displaces and replaces part of another reactant. In double displacement reaction, cations and anions in the reactants switch partners to form products.
<em>Options a, c, d, and e involves the displacement of a part of one of the reactants by another reactant while option b does not.</em>
Correct option = b.
Here is the full question
Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following endothermic reaction: NH4NO3(s)→NH+4(aq)+NO−3(aq) In order to measure the enthalpy change for this reaction, 1.25 g of NH4NO3 is dissolved in enough water to make 25.0 mL of solution. The initial temperature is 25.8 ∘C and the final temperature (after the solid dissolves) is 21.9 ∘C. Part A Calculate the change in enthalpy for the reaction in kilojoules per mole. (Use 1.0g/mL as the density of the solution and 4.18J/g⋅∘C as the specific heat capacity.) Express your answer to two significant figures and include the appropriate units. ΔHrxn = ??? kJ/mol
Answer:
26 kJ / mol
Explanation:
Given that;
The mass of NH₄NO₃ = 1.25 g
Number of moles of NH₄NO₃ = Mass of NH₄NO₃ / Molar Mass of NH₄NO₃
Number of moles of NH₄NO₃= 1.25 g / 80.043 g/mol
Number of moles of NH₄NO₃= 0.016 mol
Volume of solution = 25.0 mL
Density of Solution = 1.0g/mL
Since;
Mass of Solution = Density x Volume
= 1.0g/mL × 25.0mL
= 25 g
Heat Generated (Q) =
Q= 25g × 4.18 J/g°C x (25.8°C - 21.9°C)
Q = 407.55 J
Q = 407 × 10 ⁻³ kJ
Q = 0.40755 kJ
Δ =
=
= 25.47 kJ/ mol
~ 26 kJ / mol
Therefore, the change in enthalpy for the reaction in kilojoules per mole = 26 kJ / mol