Which is a diatomic molecule? A)He B)O2 C)NaCl D)CuF2

List two things you know about nonrenewable energy

Contact [7]

It is natural and u can't by it

6 0

3 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

A solution is 0.10 M in Pb(NO3)2 and 0.10 M in AgNO3. Solid NaI is added until the second solid compound is on the verge of prec

nekit [7.7K]

Answer:

The compound which will precipitate first will be AgI with $2.9X10^{-4}$

Explanation:

In order to precipitate a salt solution the ionic product of salt must exceed the solubility product.

Given:

Ksp of AgI = $1.5X10^{-16}$

Ksp of PbI2= $1.5X10^{-9}$

As Ksp of AgI is very low it will precipitate faster than lead iodide.

Now, higher the concentration of AgI solution taken faster its precipitation.

In the given choice the highest concentration solution of AgI is $2.9X10^{-4}$

4 0

3 years ago

What are some chemical properties of a rock?

noname [10]

Answer:Properties that help geologists identify a mineral in a rock are: color, hardness, luster, crystal forms, density, and cleavage. Crystal form, cleavage, and hardness are determined primarily by the crystal structure at the atomic level. Color and density are determined primarily by the chemical composition.

8 0

4 years ago

Which observation indicates that the kinetic molecule theory has limited use for describing a certain gas

tekilochka [14]

Answer:

Please Mark as Brainliest!!!!!!!!!!

Explanation:

Increasing pressure is causing a smaller change in gas volume. The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain pressured and temperature

5 0

4 years ago