Department of Biology, Niagara University, Niagara University, New York 14109, USA.
Adv Physiol Educ. 2009 Dec;33(4):323-8. doi: 10.1152/advan.00073.2009.
Successful learning of many aspects in physiology depends on a meaningful understanding of fundamental chemistry concepts. Two conceptual diagnostic questions measured student understanding of the chemical equilibrium underlying calcium and phosphate homeostasis. One question assessed the ability to predict the change in phosphate concentration when calcium ions were added to a saturated calcium phosphate solution. Fifty-two percent of the students correctly predicted that the phosphate concentration would decrease in accord with the common ion effect. Forty-two percent of the students predicted that the phosphate concentration would not change. Written explanations showed that most students failed to evoke the idea of competing chemical equilibria. A second question assessed the predicted change in calcium concentration after solid calcium phosphate was added to a saturated solution. Only 11% of the students correctly predicted no change in calcium concentration; 86% of the students predicted an increase, and many based their prediction on a mistaken application of Le Chatelier's principle to heterogeneous equilibria. These results indicate that many students possess misconceptions about chemical equilibrium that may hamper understanding of the processes of calcium and phosphate homeostasis. Instructors can help students gain greater understanding of these physiochemical phenomena by adopting strategies that enable students achieve more accurate conceptions of chemical equilibria.
生理学的许多方面的成功学习都依赖于对基本化学概念的有意义的理解。两个概念性诊断问题衡量了学生对钙和磷酸盐动态平衡所基于的化学平衡的理解。一个问题评估了在向饱和的钙磷酸盐溶液中添加钙离子时预测磷酸盐浓度变化的能力。52%的学生正确预测磷酸盐浓度会根据同离子效应而降低。42%的学生预测磷酸盐浓度不会改变。书面解释表明，大多数学生未能唤起竞争化学平衡的概念。第二个问题评估了在向饱和溶液中添加固体钙磷酸盐后钙浓度的预测变化。只有 11%的学生正确预测钙浓度不会改变；86%的学生预测钙浓度会增加，许多学生的预测是基于对勒沙特列原理在非均相平衡中的错误应用。这些结果表明，许多学生对化学平衡存在误解，这可能会妨碍他们理解钙和磷酸盐动态平衡的过程。教师可以通过采用使学生对化学平衡形成更准确概念的策略，帮助学生更好地理解这些生理化学现象。
