__________ is unchanged when a solution is diluted by the addition of solvent

It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry

vesna_86 [32]

Explanation:

Relation between pressure, latent heat of fusion, and change in volume is as follows.

$\frac{dP}{dT} = \frac{L}{T \times \Delta V}$

Also, $\frac{L}{T} = \Delta S^{fusion}_{m}$

where, $\Delta V^{fusion}_{m}$ is the difference in specific volumes.

Hence, $\frac{dP}{dT} = \frac{\Delta S^{fusion}_{m}}{\Delta V^{fusion}_{m}}$

As, $\Delta S^{fusion}_{m} = \frac{L}{T} = \frac{6010}{273.15}$ = 22.0 J/mol K

And, $\Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}$ ...... (1)

where, $d_{H_{2}O}$ = density of water

$d_{ice}$ = density of ice

M = molar mass of water = $18.02 \times 10^{-3} kg$

Therefore, using formula in equation (1) we will calculate the volume of fusion as follows.

$\Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}$

= $\frac{18.02 \times 10^{-3}}{997} - \frac{18.02 \times 10^{-3}}{920}$

= $-1.51 \times 10^{-6}$

Therefore, calculate the required pressure as follows.

$\frac{dP}{dT} = \frac{22}{-1.51 \times 10^{-6}}$

= $1.45 \times 10^{7} Pa/K$

or, = 145 bar/K

Hence, for change of 1 degree pressure the decrease is 145 bar and for 4.7 degree change dP = $145 \times 4.7 bar$

= 681.5 bar

Thus, we can conclude that pressure should be increased by 681.5 bar to cause 4.7 degree change in melting point.

5 0

3 years ago

Phosphate buffers are commonly used in biological research. If a small amount of strong acid is added to a buffer solution that

lozanna [386]

Answer:

A) [H3PO4] will increase, [KH2PO4] will decrease, and pH will slightly decrease.

Explanation:

A buffer is a solution which resists changes to its pH when a small amount of acid or base is added to it.

Buffers consist of a weak acid (HA) and its conjugate base (A–) or a weak base and its conjugate acid. Weak acids and bases do not completely dissociate in water, and instead exist in solution as an equilibrium of dissociated and undissociated species. When a small quantity of a strong acid is added to a buffer solution, the conjugate base, A-, reacts with the hydrogen ions from the added acid to form the weak acid and a salt thereby removing the extra hydrogen ions from the solution and keeping the pH of the solution fairly constant. On the other hand, if a small quantity of a strong base is added to the buffer solution, the weak acid dissociates further to release hydrogen ions which then react with the hydroxide ions of the added base to form water and the conjugate base.

For example, if a small amount of strong acid is added to a buffer solution that is 0.700 M H3PO4 and 0.700 M KH2PO4, the following reaction is obtained:

KH₂PO₄ + H+ ----> K+ + H₃PO₄

Therefore, [H₃PO₄] will increase, [KH₂PO₄] will decrease, and pH will slightly decrease.:

4 0

3 years ago

The energy needed to remove an electron from an atom is called

Arlecino [84]

Ionization energy, also called ionization potential, in chemistry, the amount of energy required to remove an electron from an isolated atom or molecule

3 0

3 years ago

What is the density of the continental crust?

Fiesta28 [93]

Answer: Getting into the technicalities, the continental crust has a density of around 3.0 g/cm3 compared to 2.6 g/cm3 of the continental crust. In addition, the continental crust is much thicker than the oceanic crust.

Explanation:

Hope this helps! Mark me Brainliest pls :)

5 0

3 years ago

Acids

Marizza181 [45]

-Acids release hydrogen ions

-Acids taste sharp

-Some Acids can cause serious burns

The answer is "All of the above"

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<em>Hope this helps! Please mark brainliest!!!</em>

6 0

2 years ago