Answer:
The change in internal energy is - 1.19 kJ
Explanation:
<u>Step 1:</u> Data given
Heat released = 3.5 kJ
Volume calorimeter = 0.200 L
Heat release results in a 7.32 °C
Temperature rise for the next experiment = 2.49 °C
<u>Step 2:</u> Calculate Ccalorimeter
Qcal = ccal * ΔT ⇒ 3.50 kJ = Ccal *7.32 °C
Ccal = 3.50 kJ /7.32 °C = 0.478 kJ/°C
<u>Step 3:</u> Calculate energy released
Qcal = 0.478 kJ/°C *2.49 °C = 1.19 kJ
<u>Step 4:</u> Calculate change in internal energy
ΔU = Q + W W = 0 (no expansion)
Qreac = -Qcal = - 1.19 kJ
ΔU = - 1.19 kJ
The change in internal energy is - 1.19 kJ
Answer:
Option D. 30 g
Explanation:
The balanced equation for the reaction is given below:
2Na + S —> Na₂S
Next, we shall determine the masses of Na and S that reacted from the balanced equation. This is can be obtained as:
Molar mass of Na = 23 g/mol
Mass of Na from the balanced equation = 2 × 23 = 46 g
Molar mass of S = 32 g/mol
Mass of S from the balanced equation = 1 × 32 = 32 g
SUMMARY:
From the balanced equation above,
46 g of Na reacted with 32 g of S.
Finally, we shall determine the mass sulphur, S needed to react with 43 g of sodium, Na. This can be obtained as follow:
From the balanced equation above,
46 g of Na reacted with 32 g of S.
Therefore, 43 g of Na will react with = (43 × 32)/46 = 30 g of S.
Thus, 30 g of S is needed for the reaction.
B: produces energy for the cell
Answer: 10.99
Explanation: because you take the Cao 13.9 and take CO2 which is 10.99 and it makes 24.8 . Which is CaCO3.
*** 2 ***
<span>if we assume volume NaCl + volume H2O = volume H2O.. i.e.. NaCl does not effect volume </span>
<span>therefore.. the units of.. </span>
<span>.. M = moles NaCl / L solution ≈ moles NaCl / L H2O </span>
<span>.. density = grams NaCl / L solution ≈ grams NaCl / L H2O </span>
<span>again.. that is our assumption </span>
<span>so we can readily see that </span>
<span>.. M = (1 mol NaCl / ___g NaCl) x (__g NaCl / L H2O) + 0 </span>
<span>ie.. </span>
<span>.. M = (1 mol NaCl / 58.5g NaCl) x density solution + 0 </span>
<span>so.. we would expect.. </span>
<span>.. m = 0.01709 mol / g </span>
<span>.. b = 0 </span>
