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
Answer:
Explanation:
Please tell me if im wrong
Question 6. 6. In a reaction between vinegar and antacid tablets, the antacid is the limiting reagent. At constant pressure and temperature, three tablets produce 600 cm3 of gas. What volume will two tablets produce?
(Points : 3)
400 cm3
600 cm3
800 cm3
1,200 cm3****
Question 7. 7. You breathe in 3.0 L of pure oxygen at 298 K and 1,000 kPa. How many moles of oxygen did you take in? (Use the ideal gas law: PV = nRT where R = 8.31 L-kPa/mol-K.)
(Points : 3)
0.05 moles
1.21 moles*****
2.42 moles
20.0 moles
Question 8. 8. Consider a gas at STP in a container of 22.4 L. If you apply the ideal gas law, what is the approximate value of n?
(Points : 3)
0.5
8.31
224****
1
Question 9. 9. Water boils at 100°C. What is that temperature on the Kelvin scale?
(Points : 3)
213 K
325 K****
333 K
373 K
Question 10. 10. The average speeds of gas molecules in cylinders A, B, C, and D are 0.001 m/s, 0.05 m/s, 0.1 m/s, and 0.5 m/s, respectively. Which cylinder contains gas that is closest to absolute zero?
(Points : 3)
A
B
C******
D
I suck at chemistry
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Mass determines the force of gravity like this:
If an object weight a lot it will affect the mass and gravity pulls on the object lots more when an object has lots of weight/mass.
Example: An airplane. An airplane probably weighs a ton. That is why gravity pushes it down in order for the plane to go down when it is landing or else it would be flying but never coming down. But the gravity pulling down the airplane is still there so the airplane has to be pulling the steer up in order for it to be heading straight.
Glad to help! :)
No your hypothesis was only a educated guess
Unless the accepted theory was by a scientist then you must of mested up somewhere
