Answer:
- <em>c. The reaction is spontaneous at all temperatures.</em>
Explanation:
The spontaneity of a reaction can be determined by the thermodynamic property named Gibb's free energy or simply free energy (G).
The change in the free energy of a system is defined as the difference between the increase in enthalpy (ΔH) and the product of the temperature (T) times the increase in entropy (ΔS):
The sign of ΔG tells if a reaction is spontaneous according to this:
- ΔG < 0, the reaction is spontaneous.
- ΔG = 0, the reaction is in equilibrium.
- ΔG > 0, the reaction is not spontaneous.
The question states that a reaction is exothermic, and its entropy change is positive. That means:
- Exhotermic: ΔH < 0
- Positive entropy change: ΔS > 0
Remember that the temperature is stated in absolute scale, so T is always positive.
Hence, ΔG = ΔH - T ΔS = (negative) - T (positive) = (negative) + (negative) = negative.
<u>Conclusion</u>: since ΔG is negative, regardless the temperature, you conclude that<em><u> the reaction is spontaneous at all temperatures, which is the option c.</u></em>
Answer:
The biological sample that pregnancy tests use to detect pregnancy is urine
Answer:
The freezing point of the solution is -1.4°C
Explanation:
Freezing point decreases by the addition of a solute to the original solvent, <em>freezing point depression formula is:</em>
ΔT = kf×m×i
<em>Where Kf is freezing point depression constant of the solvent (1.86°C/m), m is molality of the solution (Moles CaBr₂ -solute- / kg water -solvent) and i is Van't Hoff factor.</em>
Molality of the solution is:
-moles CaBr₂ (Molar mass:
189.9g ₓ (1mol / 199.89g) = 0.95 moles
Molality is:
0.95 moles CaBr₂ / 3.75kg water = <em>0.253m</em>
Van't hoff factor represents how many moles of solute are produced after the dissolution of 1 mole of solid solute, for CaBr₂:
CaBr₂(s) → Ca²⁺ + 2Br⁻
3 moles of ions are formed from 1 mole of solid solute, Van't Hoff factor is 3.
Replacing:
ΔT = kf×m×i
ΔT = 1.86°C/m×0.253m×3
ΔT = 1.4°C
The freezing point of water decreases in 1.4°C. As freezing point of water is 0°C,
<h3>The freezing point of the solution is -1.4°C</h3>
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Answer:
b. cellulose.
Explanation:
Cellulose is a polysaccharide consisting of a long chain of repeating glucose units (i.e., β-D-glucose units) that produce long unbranched chains. Cellulose can be considered as a natural polymer (i.e., a non-modified carbohydrate) because it is composed of repeated chains of β-D-glucose molecules stuck together. The cellulose polysaccharide is a principal component of plant cell walls.
Answer:
Charles's law states that V1 / T1 = V2 / T2. However, you must make sure that T is in Kelvin, not C.
1.19E6 / (11 + 273) = V2 / (113 + 273)
V2 = 1.62E6
Explanation:
Gases expand when heated if the container they are in is flexible. When the gas is heated its molecules move faster and faster. The collisions of the gas particles with the flexible container wall expand.
