What makes a solution a homogeneous mixture? Question 13 options:

How many formula units make up 24.2 g of magnesium chloride (MgCl2)?<br><br> Help!!

NNADVOKAT [17]

Answer:

Approximately $1.53 \times 10^{23}$ formula units ( $0.254\; \rm mol$ ).

Explanation:

Refer to a modern periodic table for the relative atomic mass of magnesium ( $\rm Mg$ ) and chlorine ( $\rm Cl$ ):

$\rm Mg$ : $24.305$ .
$\rm Cl$ : $35.45$ .

In other words, the mass of $1\; \rm mol$ of $\rm Mg$ atoms would be (approximately) $24.305\; \rm g$ .

Likewise, the mass of $1\; \rm mol$ of $\rm Cl$ atoms would be approximately $35.45\; \rm g$ .

One formula unit of the ionic compound $\rm MgCl_{2}$ includes exactly as many atoms as there are in the given formula. The formula mass of a compound is the mass of $1\; \rm mol$ of the formula units of this compound.

The formula $\rm MgCl_{2}$ includes one $\rm Mg$ atom and two $\rm Cl$ atoms.

Hence, every formula unit of $\rm MgCl_{2} \!$ would include the same number of atoms: one $\rm Mg\!$ atom and two $\rm Cl\!$ atoms. There would be $1\; \rm mol$ of $\rm Mg$ atoms and $2\; \rm mol$ of $\rm Cl$ atoms in $1\; \rm mol\!$ of $\rm MgCl_{2}$ formula units.

Thus, the mass of $1\; \rm mol\!$ of $\rm MgCl_{2}$ formula units would be equal to the mass of $1\; \rm mol$ of $\rm Mg$ atoms plus the mass of $2\; \rm mol$ of $\rm Cl$ atoms. (The mass of $1\; \rm mol\!\!$ of each atom could be found from the relative atomic mass of each element.)

$\begin{aligned}& M({\rm MgCl_{2}}) \\ =\; & 24.305\; {\rm g \cdot mol^{-1}} + 2\times {\rm 35.45 \; \rm g \cdot mol^{-1}} \\ =\; & 95.205\; \rm g \cdot mol^{-1}\end{aligned}$ .

In other words, the formula mass of $\rm MgCl_{2}$ is $95.205\; \rm g \cdot mol^{-1}$ .

Therefore, the number of formula units in $m = 24.2\; \rm g$ of $\rm MgCl_{2}$ would be:

$\begin{aligned}n &= \frac{m({\rm MgCl_{2}})}{M({\rm MgCl_{2}})} \\ &= \frac{24.2\; \rm g}{95.205\; \rm g\cdot mol^{-1}} \\ & \approx 0.254\; \rm mol\end{aligned}$ .

Multiple $n$ by Avogadro's Number $N_{A} \approx 6.022 \times 10^{23}\; \rm mol^{-1}$ to estimate the number of formula units in $0.254\; \rm mol$ :

$\begin{aligned}N &= n \cdot N_{A} \\ &\approx 0.254\; \rm mol \times 6.022 \times 10^{23}\; \rm mol^{-1} \\ &\approx 1.53\times 10^{23}\end{aligned}$ .

6 0

2 years ago

the average speeds of gas molecules in.cylinders A,b,c,d are 0.01 m/s, 0.005m/s ,0.1 m/s and 0.5 m/s, respectively .which cylind

Darya [45]

<span>The average speed of the gas is related to the kinetic energy of the gas. The kinetic energy of the gas is also related to the temperature of the gas. If the average speed of the gas is closer to zero, it means that it has very low motion or kinetic energy. This can be inferred that the gas has a very low temperature. At absolute zero, the motion of all the gas molecules stops. This means that the kinetic energy of the gas is also zero. Zero kinetic energy means zero average speed.</span> <span>So, the answer is cylinder B. The average speed of the gas in cylinder B is closest to zero.</span>

8 0

2 years ago

to show the electron configuration for an atom, when would it be better to use an orbital notation than to use a written configu

sineoko [7]

The aim is to use less space while demonstrating the distribution of electrons in shells

If you want to depict how an atom's electrons are scattered across its subshells, an orbital notation is more suited.

This is due to the fact that some atoms have unique electronic configurations that are not readily apparent from textual configurations.

<h3>How does electron configuration work?</h3>

The placement of electrons in orbitals surrounding an atomic nucleus is known as electronic configuration, also known as electronic structure or electron configuration.

<h3>What sort of electron arrangement would that look like?</h3>

For instance: You can see that oxygen contains 8 electrons on the periodic table.
These 8 electrons would fill in the following order: 1s, 2s, and finally 2p, according to the aforementioned fill order. O 1s22s22p4 would be oxygen's electron configuration.

learn more about electronic configuration here

brainly.com/question/26084288

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7 0

1 year ago

Who arranged the elements according to atomic mass and used the arrangement to predict the properties of missing element?

Marina CMI [18]

Answer:

Dmitri Mendeleev

Explanation:

Dmitri Mendeleev a Russian Chemist arranged elements on the periodic table according to their atomic mass. He used this arrangement to predict some of the properties of the missing element.

Dmitri Mendeleev around 1869 described the periodic table.
The table was based on the periodic law which states that "chemical properties of elements are a periodic function of their atomic weights".
In the Mendeleev table, elements are arranged by atomic weights with recurring properties in a periodic manner.

3 0

2 years ago

Which of the following substances are not homogeneous mixtures?

Tanya [424]

Answer: it’s B

Explanation:

7 0

2 years ago