(PRACTICE) QUIZ Unit 4 5 Questions – 15 minutes 1. _______ is an indication of how closely a measurement made by the observer is to the true value. 2. A pH of 10 is ____ times more _____ (acidic or basic?) than a pH of 8. 3. If a solution has a pH of 7.29, what is the hydrogen ion concentration ([H+])? Use the correct significant figures for logarithms. 4. If the hydrogen ion concentration ([H+]) of a given solution is 9.1x10-7, what is the pH? Use the correct significant figures for logarithms. 5. In facilitated diffusion, molecules move from an area of ______ concentration to an area of ______ concentration. The End Please turn in your quiz form to Kat then you can leave for the day. Answer Key 1. Accuracy is an indication of how closely a measurement made by the observer is to the true value. 2. A pH of 10 is 100 times more basic (acidic or basic?) than a pH of 8. 3. If a solution has a pH of 7.29, what is the hydrogen ion concentration ([H+])? Use the correct significant figures for logarithms. [H+]=10-pH so 10-7.29=[H+]= 5.1 x 10-8 (mantissa is 2 so sigfigs are 2) 4. If the hydrogen ion concentration ([H+]) of a given solution is 9.1x10-7, what is the pH? Use the correct significant figures for logarithms. pH=-log[H+] so pH=log(9.1x10-7) = 6.04 (the 2 sigfigs in 9.1 so need 2 digits after decimal for the mantissa) 5. In facilitated diffusion, molecules move from an area of high concentration to an area of low concentration.