A student is investigating the pH of a substance. The pH of the unknown substance is 5.4. Which of the following substances is the unknown substance most likely to be? How do you know? Answer using a CER format using the above graphic organizer. Use evidence from the simulation in your response. Digitally complete, and then email a copy of the graphic organizer OR print and take a photo and email.
Substance A, which has a H3O+ concentration of 4x10^-6
Substance B, which has a H3O+ concentration of 6x10^-7
Substance C, which has a H3O+ concentration of 55
Substance D, which has a H3O+ concentration of 1.3x10^-1

Explanation:

pH is a measure of the concentration of H₃O⁺ ions in a solution.

It is defined as:

For the given substances

Sustance        [H₃O⁺]         pH = - log [H₃O⁺]

                           M

    A                4×10⁻⁶         -log (4×10⁻⁶) = 5.4 ← answer

    B                6×10⁻⁷         -log (6×10⁻⁷) = 6.2

    C               error                      - - - - - -

    D               1.3×10⁻¹        -log (1.3×10⁻¹) = 0.89

Thus, the unknown substace most likely is A.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.