Question

95. Because atoms, molecules, and ions are very small, they are counted in units of moles, where 1 mole = 6.022 × 1023 molecules. Concentration of ions in a liquid is measured in units of moles per liter. The measure of the acidity of a liquid is called the pH of the liquid and is given by the formula

pH = −log(H),
where H is the concentration of hydrogen ions in units of moles per liter.
a. Water has a pH value of 7.0. How many hydrogen ions are in one liter of water?

Answer 1

The concentration of hydrogen ions in one liter of water can be calculated using the formula pH=-log(H), where H is the concentration of hydrogen ions in moles per liter. Since water has a pH of 7.0, there are 10^-7 moles of hydrogen ions in one liter of water.

Step-by-step explanation:

The concentration of hydrogen ions in pure water is 1 x 10^-7 moles per liter. To calculate the number of hydrogen ions in one liter of water, we can use the formula pH=-log(H). Since water has a pH value of 7.0, we can substitute 7.0 for pH:

7.0 = -log(H)

Now we can solve for H:

H = 10^-7

This means there are 10^-7 moles of hydrogen ions in one liter of water.

Answer 2

There are 10⁻⁷ hydrogen ions in one-liter water

Step-by-step explanation:

Hi there!

a. If the pH = 7.0, then:

-log(H) = 7.0

multiply both sides of the equation by -1

log(H) = -7.0

Apply 10ˣ to both sides

10^(log (H)) = 10⁻⁷

(H) = 10⁻⁷

There are 10⁻⁷ hydrogen ions in one-liter water.

Why 10^(log (H)) = (H)?

Let´s consider this function:

y = 10^(log x)

(Apply log to both sides)

log y = log 10^(log x)

(Apply logarithmic property: log xᵃ = a · log x)

log y = log x · log 10

(log 10 = 1)

log y = log x

y = x

(since y = 10^(log x) and y = x):

10^(log x) = x

That´s why 10^(log (H)) = (H)