Answer:
W = -120 KJ
Explanation:
Since the piston–cylinder assembly undergoes an isothermal process, then the temperature is constant.
Thus; T1 = T2 = 400K
change in entropy; ΔS = −0.3 kJ/K
Formula for change in entropy is written as;
ΔS = Q/T
Where Q is amount of heat transferred.
Thus;
Q = ΔS × T
Q = -0.3 × 400
Q = -120 KJ
From the first law of thermodynamics, we can find the workdone from;
Q = ΔU + W
Where;
ΔU is Change in the internal energy
W = Work done
Now, since it's an ideal gas model, the change in internal energy is expressed as;
ΔU = m•C_v•ΔT
Where;
m is mass
C_v is heat capacity at constant volume
ΔT is change in temperature
Now, since it's an isothermal process where temperature is constant, then;
ΔT = T2 - T1 = 0
Thus;
ΔU = m•C_v•ΔT = 0
ΔU = 0
From earlier;
Q = ΔU + W
Thus;
-120 = 0+ W
W = -120 KJ
<span>First - you need the empirical formula.
So, assume you have 100 g of the compound.
If so, you'll have 54.53 gram of C, 9.15 g of H and 36.32 g of O. Find the number of moles of each.
54.53 g C (1 mole C / 12.01 g C) = 4.540
9.15 g H (1 mole H / 1.008 g H) = 9.077
36.32 g O (1 mole O / 15.9994 g O) = 2.270
Take the smallest number found and divide the others by it to get the empirical formula.
4.540/2.270 = 2.
9.077/2.270 = 4.
2.270/2.270 =1.
So, that gives you the empirical formula of C2H4O.
Find the weight of this compound. C = 12, H = 1, O = 16. So, C2H4O is 44 amu.
132/44 = 3.
So, 3 (C2 H4 O) = C6H12O3 = molecular formula.</span>
<u>Answer:</u>
density of solid = 4.5 g/cm³
<u>Explanation:</u>
density = mass ÷ volume
• We know the mass of the object (135 g). We need to calculate the volume:
Volume = length × width × thickness
= 5 cm × 3 cm × 2 cm
= 30 cm³
• Now we can calculate the solid's density:
density = 135 g ÷ 30 cm³
= 4.5 g/cm³
Complete Question:
A certain ionic compound X has a solubility in water of .765g/ml at 5 degrees C. Calculate the mass of X that's dissolved in 3 L of a saturated solution of X in the water at this temp. Be sure your answer has the correct unit symbol and significant digits.
Answer:
2.29 kg
Explanation:
A saturated solution is a solution that has the maximum amount of solute diluted at it, so if more solute is added, it will precipitate. The solutions can also be unsaturated (when more solute can be dissolved) or supersaturated (when there is more solute dissolved than the maximum. It's a very unstable solution).
The saturation is measured by the solubility, which indicates how much mass of the solute can be added to a certain volume of the solvent. So, the solubility (S) is the mass (m) divided by the volume (V).
For a solution with 3 L = 3000 mL,
S = m/V
0.765 = m/3000
m = 3000 * 0.765
m = 2295 g
m = 2.29 kg
The correct answer is :
the purpose of heating the mixture is to accelerate the reaction and mix the reagent.
The explanation:
Many organic reactions are slow and can take an extended period of time to achieve any noticeable effect so heating is often used to increase the rate of reaction. However, many organic compounds have low boiling points and will vaporise upon exposure to such high heat, preventing the reaction from proceeding in full.
so, heating is used. This refers to heating a solution with an attached condenser to prevent reagents from escaping
