The pH reading of a sample of each substance is given. Calculate the hydrogen ion concentration of the substance. Give your answers in scientific notation, correct to one decimal place.

(a) Tomatoes: [tex]$pH = 4.1$[/tex]
[tex]\left[ H^{+} \right] = \square \times 10^{- \square} \, M[/tex]

(b) Human blood: [tex]$pH = 7.3$[/tex]
[tex]\left[ H^{+} \right] = \square \times 10^{- \square} \, M[/tex]



Answer :

To solve the problem of finding the hydrogen ion concentration [tex]\([\text{H}^+]\)[/tex] for given pH values for two substances, we will follow the definition of pH. The pH of a solution is defined by the formula:

[tex]\[ \text{pH} = -\log[\text{H}^+] \][/tex]

We can rearrange this formula to solve for the hydrogen ion concentration:

[tex]\[ [\text{H}^+] = 10^{-\text{pH}} \][/tex]

Now we will apply this formula to both the given pH values.

### (a) Tomatses: [tex]\( \text{pH} = 4.1 \)[/tex]

1. Calculate the hydrogen ion concentration [tex]\([\text{H}^+]\)[/tex]:

[tex]\[ [\text{H}^+] = 10^{-4.1} \][/tex]

2. Expressing the result in scientific notation and rounding to one decimal place:

[tex]\[ 10^{-4.1} = 7.943282347242822 \times 10^{-5} \][/tex]

Rounded to one decimal place and in scientific notation, this becomes:

[tex]\[ [\text{H}^+] \approx 7.9 \times 10^{-5} \, \text{M} \][/tex]

Thus, for Tomatses,
[tex]\[ \left[ \text{H}^+ \right] = 7.9 \times 10^{-5} \, \text{M} \][/tex]

### (b) Human blood: [tex]\( \text{pH} = 7.3 \)[/tex]

1. Calculate the hydrogen ion concentration [tex]\([\text{H}^+]\)[/tex]:

[tex]\[ [\text{H}^+] = 10^{-7.3} \][/tex]

2. Expressing the result in scientific notation and rounding to one decimal place:

[tex]\[ 10^{-7.3} = 5.011872336272725 \times 10^{-8} \][/tex]

Rounded to one decimal place and in scientific notation, this becomes:

[tex]\[ [\text{H}^+] \approx 5.0 \times 10^{-8} \, \text{M} \][/tex]

Thus, for human blood,
[tex]\[ \left[ \text{H}^+ \right] = 5.0 \times 10^{-8} \, \text{M} \][/tex]

### Summary:

(a) Tomatses:
[tex]\[ \left[ \text{H}^+ \right] \approx 7.9 \times 10^{-5} \, \text{M} \][/tex]

(b) Human blood:
[tex]\[ \left[ \text{H}^+ \right] \approx 5.0 \times 10^{-8} \, \text{M} \][/tex]