The pH of lemon juice is about 2.3.

(a) What is the concentration of hydrogen ions in lemon juice?
The concentration is moles per liter. [Hint: pH = $\scriptstyle -\log{ \lbrack H^+ \rbrack }$ ]

(b) A person squeezes 4 oz of lemon juice into a cup. Based on your answer to part (a), how many hydrogen ions does this juice contain? Your answer should be a very large number, so in order to fit your answer in the box, you should use scientific notation. For example you could enter $2.45 \times 10^{18}$ by entering 2.45 * 10^(18) instead of 2,450,000,000,000,000,000.

Number of ions: ions. [Hint: 1 liter = 30.3 ounces, and one mole of Hydrogen ions is $6.02\times 10^{23}$ Hydrogen ions. Note that the concentration you found in (a) is given in moles per liter.]