Answer:
[Na+] = 0.1528 M
[S^2-] = 0.0764 M
Explanation:
Step 1: Data given
MAss of Na2S = 5.96 grams
Volume of solution = 1.00 L
Molar mass Na2S = 78.045 g/mol
Step 2: Calculate moles Na2S
Moles Na2S = Mass Na2S / molar mass Na2S
Moles Na2S = 5.96 grams / 78.045 g/mol
Moles Na2S = 0.0764 moles
Step 3: Calculate moles ions
For 1 mol Na2S we have 2 moles Na+ and 1 mol S^2-
For 0.0764 moles Na2S we have 0.0764 moles S^2- and 2*0.0764 = 0.1528 moles Na+
Step 4: Calculate concentration of ions
[Na+] = 0.1528 moles / 1 L = 0.1528 M
[S^2-] = 0.0764 moles / 1L = 0.0764 M
Answer:
Final Temperature = 28.2 oC
Explanation:
Information given;
Mass of Iron = 20.8g
Initial Temperature of Iron = 100C
Mass of water = 55.3g
Initial temperature of water = 25.3 C
The presence of a coffee cup calorimeter hints that there is no heat loss to the surrounding and that the iron and water are at thermal equilibrium.
Thermal equilibrium means that there is no heat transfer going on between the bodies, which simply means that the bodies are at the same temperature.
Hence, both bodies would the same final temperature (T2)
H = M * C * ΔT (For iron)
H = 20.8 * 0.449 * ( 100 - T2)
H = 9.3392 ( 100 - T2)
H = 933.92 - 9.3392T2
H = M * C * ΔT (For water)
H = 55.3 * 4.184 * (T2 - 25.3)
H = 231.3752 (T2 - 25.3)
H = 231.3752T2 - 5853.79
Since they are in thermal equilibrium it means H (Iron) = H (water).
This leads to;
933.92 - 9.3392T2 = 231.3752T2 - 5853.79
231.3752T2 + 9.3392T2 = 5853.79 + 933.92
240.7144 T2 = 6787.71
T2 = 28.2 oC
This cant be answered unless you have mutiple choice options and if so you need to post them next time
Solar core I think... i hope it helps
