(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
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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.