## anonymous one year ago PLEASE HELP!!! If you ever swam in a pool and your eyes began to sting and turn red, you felt the effects on an incorrect pH level. pH measures the concentration of hydronium ions and can be modeled by the function p(t) = −log10t. The variable t represents the amount of hydronium ions; p(t) gives the resulting pH level. Water at 25 degrees Celsius has a pH of 7. Anything that has a pH less than 7 is called acidic, a pH above 7 is basic, or alkaline. Seawater has a pH just more than 8, whereas lemonade has a pH of approximately 3.

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1. anonymous

1. Create a graph of the pH function either by hand or using technology. Locate on your graph where the pH value is 0 and where it is 1. You may need to zoom in on your graph. 2. The pool maintenance man forgot to bring his logarithmic charts, and he needs to raise the amount of hydronium ions, t, in the pool by 0.50. To do this, he can use the graph you created. Use your graph to find the pH level if the amount of hydronium ions is raised to 0.50. Then, convert the logarithmic function into an exponential function using y for the pH.

2. anonymous

@hero @Preetha @nincompoop @Michele_Laino @ganeshie8 @myininaya @pooja195

3. Michele_Laino

we have to use the definition of pH: $\Large pH = - \log \left[ {{H^ + }} \right]$

4. Michele_Laino

more precisely: $\Large pH = - {\log _{10}}\left[ {{H^ + }} \right]$

5. anonymous

ok @michele_laino

6. Michele_Laino

you have to make a graph using a log scale, like this: |dw:1438104451173:dw|

7. Michele_Laino

namely you have to use a logarithmic scale for horizontal axis

8. Michele_Laino

for part B we can write this: $\begin{gathered} y = - {\log _{10}}\left[ {{H^ + }} \right] = {\log _{10}}\left( {\frac{1}{{\left[ {{H^ + }} \right]}}} \right) \hfill \\ \hfill \\ \frac{1}{{\left[ {{H^ + }} \right]}} = {10^y} \Rightarrow \left[ {{H^ + }} \right] = {10^{ - y}} \hfill \\ \end{gathered}$

9. Michele_Laino

$\Large \begin{gathered} y = - {\log _{10}}\left[ {{H^ + }} \right] = {\log _{10}}\left( {\frac{1}{{\left[ {{H^ + }} \right]}}} \right) \hfill \\ \hfill \\ \frac{1}{{\left[ {{H^ + }} \right]}} = {10^y} \Rightarrow \left[ {{H^ + }} \right] = {10^{ - y}} \hfill \\ \end{gathered}$

10. Michele_Laino

where $\left[ {{H^ + }} \right]$ represents the amount of hydronium ions

11. anonymous

would that be the x? and ph = y

12. Michele_Laino

yes!

13. Michele_Laino

you can use the logarithmic paper for part A

14. anonymous

ok @Michele_Laino