To convert from mass of A to moles of B in a stoichiometry problem, the following steps are followed:

A baseball player hits a ball. Which is the best description of the energy of the ball as it flies over the pitcher’s head?

Elan Coil [88]

The right option is; b. mechanical

Mechanical energy is the best description of the energy of the ball as it flies over the pitcher’s head.

Mechanical energy is the energy that an object acquires due to its position or due to its motion. From the question, the baseball player has chemical potential energy (stored as food) which is transformed into work. As the baseball player hits the ball, there is energy exchange in which the ball acquires energy to perform its work. The energy obtained by the ball upon which work is done is called mechanical energy.

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If you have 100 ml of a 0.10 m tris buffer (pka 8.3) at ph 8.3 and you add 3.0 ml of 1.0 m hcl, what will be the new ph?

sukhopar [10]

The new pH is 7.69.

According to Hendersen Hasselbach equation;

The Henderson Hasselbalch equation is an approximate equation that shows the relationship between the pH or pOH of a solution and the pKa or pKb and the ratio of the concentrations of the dissociated chemical species. To calculate the pH of the buffer solution made by mixing salt and weak acid/base. It is used to calculate the pKa value. Prepare buffer solution of needed pH.

pH = pKa + log10 ([A–]/[HA])

Here, 100 mL of 0.10 m TRIS buffer pH 8.3

pka = 8.3

0.005 mol of TRIS.

∴ $8.3 = 8.3 + log \frac{[0.005]}{[0.005]}$

<em> </em>inverse log 0 = $\frac{[B]}{[A]}$

$\frac{[B]}{[A]} = 1$

Given; 3.0 ml of 1.0 m hcl.

pka = 8.3

0.003 mol of HCL.

$pH = 8.3 + log \frac{[0.005-0.003]}{[0.005+0.003]}\\pH = 8.3 + log \frac{[0.002]}{[0.008]}\\\\pH = 8.3 + log {0.25}\\\\pH = 8.3 + (-0.62)\\pH = 7.69$