The atomic number identifies which of the following?

What is the result of adding KF to an equilibrium mixture of the weak acid HF?

blagie [28]

Answer D. Follow Le Chatelier's principle.

5 0

4 years ago

Assume that the batteries in a flashlight are rechargeable. What energy conversion would have to take place in order to recharge

zaharov [31]

Electrical to chemical energy

Explanation:

If the batteries in a flashlight are rechargeable, the energy conversion that would take place to recharge the battery is from electrical to chemical energy.

A battery is an electrochemical cell in which chemical reactions produces electrical currents.
This is a typical energy conversion from chemical to electrical energy.
When such batteries are to be recharged, the revere process is followed.
Electrical energy are used to drive chemical reactions.
This in turn makes the battery recharged and on its own, it can further chemical reactions to produce electrical energy.
During charging, the potential of the battery increases.

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Electrochemical reactions brainly.com/question/12174850

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7 0

4 years ago

At 45 C the volume of a certain gas is 27.5 L

wariber [46]

Regretfully, I do not know what is asked of the problem because it is not stated above. However, it is easier to answer any question pertaining to the temperature, volume, and pressure of gases by assuming that they behave ideally. With this, we'll be able to use the ideal gas law which is mathematically expressed as,
PV = nRT
where P and V are pressure and volume, respectively. n is the amount of material in mol, R is gas constant, and T is temperature.

4 0

4 years ago

A solution was prepared by dissolving 195.0 g of KCl in 215 g of water. Calculate the mole fraction of KCl. (The formula weight

defon

Answer:

Approximately $0.180$ .

Explanation:

The mole fraction of a compound in a solution is:

$\displaystyle \frac{\text{Number of moles of compound in question}}{\text{Number of moles of all particles in the solution}}$ .

In this question, the mole fraction of $\rm KCl$ in this solution would be:

$\displaystyle X_\mathrm{KCl} = \frac{n(\mathrm{KCl})}{n(\text{All particles in this soluton})}$ .

This solution consist of only $\rm KCl$ and water (i.e., $\rm H_2O$ .) Hence:

$\begin{aligned} X_\mathrm{KCl} &= \frac{n(\mathrm{KCl})}{n(\text{All particles in this soluton})}\\ &= \frac{n(\mathrm{KCl})}{n(\mathrm{KCl}) + n(\mathrm{H_2O})}\end{aligned}$ .

From the question:

Mass of $\rm KCl$ : $m(\mathrm{KCl}) = 195.0\; \rm g$ .
Molar mass of $\rm KCl$ : $M(\mathrm{KCl}) = 74.6\; \rm g \cdot mol^{-1}$ .

Mass of $\rm H_2O$ : $m(\mathrm{H_2O}) = 215\; \rm g$ .
Molar mass of $\rm H_2O$ : $M(\mathrm{H_2O}) = 18.0\; \rm g\cdot mol^{-1}$ .

Apply the formula $\displaystyle n = \frac{m}{M}$ to find the number of moles of $\rm KCl$ and $\rm H_2O$ in this solution.

$\begin{aligned}n(\mathrm{KCl}) &= \frac{m(\mathrm{KCl})}{M(\mathrm{KCl})} \\ &= \frac{195.0\; \rm g}{74.6\; \rm g \cdot mol^{-1}} \approx 2.61\; \em \rm mol\end{aligned}$ .

$\begin{aligned}n(\mathrm{H_2O}) &= \frac{m(\mathrm{H_2O})}{M(\mathrm{H_2O})} \\ &= \frac{215\; \rm g}{18.0\; \rm g \cdot mol^{-1}} \approx 11.9\; \em \rm mol\end{aligned}$ .

The molar fraction of $\rm KCl$ in this solution would be:

$\begin{aligned} X_\mathrm{KCl} &= \frac{n(\mathrm{KCl})}{n(\text{All particles in this soluton})}\\ &= \frac{n(\mathrm{KCl})}{n(\mathrm{KCl}) + n(\mathrm{H_2O})} \\ &\approx \frac{2.61 \; \rm mol}{2.61\; \rm mol + 11.9\; \rm mol} \approx 0.180\end{aligned}$ .

(Rounded to three significant figures.)

8 0

3 years ago

When liquid water changes into solid ice, it increases in ?

kramer

when liquid water changes into solid ice, it increases in mass

8 0

3 years ago

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