Answer:
CaCl2
Step-by-step explanation:
1. Antifreeze is added to a car's cooling system to prevent freezing when the air temperature is below 0 degrees. This is achieved through the use of collective properties.
When a substance freezes, its particles slow down and arrange themselves into a more ordered structure, forming a solid. However, when antifreeze is added to the cooling system, it lowers the freezing point of the water. This is because antifreeze contains substances called cryoprotectants, such as ethylene glycol or propylene glycol.
Cryoprotectants disrupt the formation of ice crystals in the water by interfering with the arrangement of water molecules. They prevent the water molecules from forming the regular, closely-packed structure that characterizes solid ice. This interference leads to a decrease in the freezing point of the solution.
For example, let's say the freezing point of pure water is 0 degrees Celsius. When antifreeze is added to the water, it disrupts the arrangement of water molecules and lowers the freezing point to, let's say, -10 degrees Celsius. As a result, the water mixed with antifreeze can stay in a liquid state even when the air temperature is below 0 degrees Celsius.
In summary, antifreeze lowers the freezing point of the water in a car's cooling system by disrupting the formation of ice crystals, allowing the liquid to remain in a usable state even at below-freezing temperatures.
2. The solution with the largest change in boiling point would be CaCl2 (calcium chloride). This is because the boiling point elevation is directly proportional to the concentration of solute particles in a solution.
When a solute, such as NaCl (sodium chloride) or CaCl2, is dissolved in a solvent like water, it breaks into ions. In the case of NaCl, it dissociates into one sodium ion (Na+) and one chloride ion (Cl-). However, CaCl2 dissociates into three ions: one calcium ion (Ca2+) and two chloride ions (2Cl-).
The presence of more particles in the solution (due to the dissociation of the solute) leads to stronger intermolecular interactions and higher boiling point elevation. Since CaCl2 forms more ions than NaCl when dissolved in water, it will have a larger change in boiling point compared to NaCl.
Therefore, the solution of CaCl2 will experience a greater increase in boiling point compared to the solution of NaCl.
In conclusion, the larger change in boiling point would be observed in the solution of CaCl2 due to the presence of a greater number of solute particles, resulting in stronger intermolecular interactions and a higher boiling point elevation.