Answer:
The first one is B, "Decreasing surface area."
Explanation:
This is because greater the surface area exposed, the more collisions that occur between the solvent and solute. I also just took the test myself and got it correct.
Explanation:
Given
The enthalpy of formation of RbF (s) is –557.7kJ/mol
The standard enthalpy of formation of RbF (aq, 1 m) is –583.8 kJ/mol
The enthalpy of solution of RbF = Enthalpy of RbF (aq) - Enthalpy of formation of RbF (s)
= -583.8 - (-557.7) kJ/mol
= -26.1 kJ/mol
The enthalpy is negative which means that the temperature will rise when RbF is dissolved.
Molar mass of CuSO4 * 5 H2O
= 63.546 + 32 + 16*4 + 5*18
= 249.546 g/mol
Mass of water in that formula: 5 * 18 = 90 g/mol
Percent by mass of water = 90 / 249.546 = 36%
<span>So, 36% of your 8.22 g is water. 0.36 * 8.22= 2.95 g of water
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