When 12.5 g of NH4NO3 is dissolved in 150.0 g of water of 25.0 °C...

Question

When 12.5 g of NH4NO3 is dissolved in 150.0 g of water of 25.0 °C in a coffee cup calorimeter, the final temperature of the solution of 19.7 °C. Assume that the specific heat of the solution is the same as that of water, 4.18 J/(g•°C). What is the ΔH per mol of NH4NO3? (LO 9.10)
NH4NO3 (s) → NH4+ (aq) + NO3−(aq) ΔH = ?
(a) +3.60 kJ
(b) +23.0 kJ
(c) +21.3 kJ
(d) −3.60 kJ

Accepted Answer

Hello everyone today, we are being given the falling problem. A 10 g sample of silver nitrate is dissolved with 200 g of water and a coffee cup calorie meter at 25 degrees Celsius. After dissolution, the temperature of the solution dropped to 23.5 degrees Celsius calculate the change in entropy per mole of silver nitrate. Use the specific heat of water which is detailed is here as the specific heat of the resulting solution. So the very first thing you want to do is they want to write the formula for the heat of our reaction. So the heat of our reaction and that's going to be as follows. Q represents the heat. This is gonna be for our reaction and it's going to be equal to the negative or the opposite of the heat of our solution. And so that formula is going to be given by the following negative mass times the specific heat capacity times are changed and our temperature and this is of course for our solution. Once again For our mass we have our 10 g for our sample and we have our 200 g for our water. This is gonna be multiplied by the specific heat of water as it was detailed that the specific heat would be the same. So that's 4.18 jewels programs C And they're gonna multiply that by the change in temperature which went from 23.5°C to 25 degrees Celsius. When we compute that we're going to get 1,316. jewels. We're gonna keep that number for later. Next we need to calculate our change in our entropy and that react. That equation is going to be the change in entropy is equal to the heat of our reaction over The number of moles that we have of silver nitrate. And so that's going to look as follows. We have ahead of our reaction, which is 1,316.7 jewels. And then to find the number of moles, we need to use the grams and convert and use the molar mass of silver nitrate to convert from grams to moles. So we have our 10 g for our silver nitrate sample and the molar mass per the periodic table Of silver nitrate. In one mole of silver nitrate is 169.87 g. When our units ultimately canceled out, we're left with 223006, We are left with 22,366. jewels. However, we must convert this into killing joules per mole. And so this is going to be We are something going to multiply by the conversion factor that one kg is equal to 10 to the third jewels. Our units of jewels canceled out. We're left with 22.37 jewels. Kill eagles per mole. As our final answer. I hope that this helped. And until next time

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