What type of physical weathering is caused by the expansion of water?

A solution is made by dissolving 23.5 grams of glucose (C6H12O6) in 0.245 kilograms of water. If the molal freezing point consta

aalyn [17]

Answer:

- 0.99 °C ≅ - 1.0 °C.

Explanation:

We can solve this problem using the relation:

ΔTf = (Kf)(m),

where, ΔTf is the depression in the freezing point.

Kf is the molal freezing point depression constant of water = -1.86 °C/m,

m is the molality of the solution (m = moles of solute / kg of solvent = (23.5 g / 180.156 g/mol)/(0.245 kg) = 0.53 m.

∴ ΔTf = (Kf)(m) = (-1.86 °C/m)(0.53 m) = - 0.99 °C ≅ - 1.0 °C.

4 0

4 years ago

2-phosphoglycerate(2PG) is converted to phosphoenolpyruvate (PEP) by the enzyme enolase. The standard free energy change(deltaGo

pogonyaev

Answer:

The correct option is: (D) -2.4 kJ/mol

Explanation:

Chemical reaction involved: 2PG ↔ PEP

Given: The standard Gibb's free energy change: ΔG° = +1.7 kJ/mol

Temperature: T = 37° C = 37 + 273.15 = 310.15 K (∵ 0°C = 273.15K)

Gas constant: R = 8.314 J/(K·mol) = 8.314 × 10⁻³ kJ/(K·mol) (∵ 1 kJ = 1000 J)

Reactant concentration: 2PG = 0.5 mM

Product concentration: PEP = 0.1 mM

Reaction quotient: $Q_{r} =\frac{\left [ PEP \right ]}{\left [ 2PG \right ]} = \frac{0.1 mM}{0.5 mM} = 0.2$

To find out the Gibb's free energy change at 37° C (310.15 K), we use the equation:

$\Delta G = \Delta G^{\circ } + 2.303 R T log Q_{r}$

$\Delta G = 1.7 kJ/mol + [2.303 \times (8.314 \times 10^{-3} kJ/(K.mol))\times (310.15 K)] log (0.2)$

$\Delta G = 1.7 + [5.938] \times (-0.699) = 1.7 - 4.15 = (-2.45 kJ/mol)$

Therefore, the Gibb's free energy change at 37° C (310.15 K): ΔG = (-2.45 kJ/mol)

4 0

3 years ago

Which sample would serve as a better buffer and therefore a better environment for aquatic life?

Ann [662]

Answer:

sample A

Explanation:

the first one because of the ppm value

6 0

2 years ago

Read 2 more answers

What is the endpoint of a titration?Select one:When there is no acid and all base.When the amount of acid and base are equal.Whe

user100 [1]

Answer:

The correct option is: When the amount of acid and base are equal

Explanation:

Titration is an analytic method that is used to determine the concentration of an unknown solution, called titrand.

In this method, standard solution of known concentration, called titrant, is taken in the burette and added drop-wise to the titrand solution in the flask, until the endpoint is reached.

In case of an acid-base titration, a pH indicator is used, which changes the color of the solution when the endpoint is reached.

The endpoint indicates the equivalence point of an acid-base titration, where the concentration of the acid and base is equal.

Therefore, the correct option is: When the amount of acid and base are equal

3 0

3 years ago

Rutherford’s gold foil experiment gave evidence that an atom is mostly empty space. true false

Sholpan [36]

The given statement is true .

<h3>What is Rutherford’s gold foil experiment?</h3>

A piece of gold foil was hit with alpha particles, which have a favorable charge. Most alpha particles went right around. This showed that the gold particles were mostly space.

The Rutherford gold leaf investigation supposed that most (99%) of all the mass of an atom is in the middle of the atom, that the nucleus is very small (105 times small than the length of the atom) and that is positively captured.

For the distribution experiment, Rutherford enjoyed a metal sheet that could be as thin as practicable. Gold is the most malleable of all known metals. It can easily be converted into very thin sheets. Hence, Rutherford established a gold foil for his alpha-ray scattering experimentation.

To learn more about Rutherford’s gold foil experiment, refer to:

brainly.com/question/4113533

#SPJ4

4 0

1 year ago