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3 years ago

Modern atomic theory states that the atom is a diffuse cloud of ________ surrounding a small, dense nucleus.

Chemistry

2 answers:

spin [16.1K]3 years ago

3 0

Electrons, hence the electron cloud

skelet666 [1.2K]3 years ago

3 0

Answer:

Electron.

Explanation:

According to modern atomic theory, the electron position is not considered to be discrete or fix. We say that there is probability of finding electron in particular area around the nucleus. so this we call as that atom is a diffuse cloud of electrons surrounding a small dense nucleus.

The electron density is maximum in shells.

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The water-gas shift reaction plays a central role in the chemical methods for obtaining cleaner fuels from coal: CO(g) + H2O(g)

taurus [48]

Answer: The concentration of carbon dioxide, hydrogen gas, carbon monoxide and water when equilibrium is re-established are 0.362 M, 0.212 M, 0.138 M and 0.138 M respectively.

Explanation:

For the given chemical reaction:

$CO(g)+H_2O(g)\rightleftharpoons CO_2(g)+H_2(g)$

The expression of $K_c$ for above reaction follows:

$K_c=\frac{[CO_2][H_2]}{[CO][H_2O]}$ ........(1)

We are given:

$[CO]_{eq}=[H_2O]_{eq}=[H_2]_{eq}=0.10M$

$[CO_2]_{eq}=0.40M$

Putting values in above equation, we get:

$K_c=\frac{0.40\times 0.10}{010\times 0.10}\\\\K_c=4$

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Moles of hydrogen gas = 0.30 mol

Volume of solution = 2.0 L

Putting values in above equation, we get:

$\text{Molarity of }H_2=\frac{0.30mol}{2L}=0.15M$

When hydrogen gas is added, the concentration of product gets increased. But, by Le-Chatelier's principle, the equilibrium will shift in the direction where concentration of product must decrease, which is in the backward direction.

Concentration of hydrogen gas when equilibrium is re-established = 0.1 + 0.15 = 0.25 M

Now, the equilibrium is shifting to the reactant side. The equation follows:

$CO(g)+H_2O(g)\rightleftharpoons CO_2(g)+H_2(g)$

Initial: 0.1 0.1 0.4 0.1

At eqllm: 0.1+x 0.1+x 0.4-x 0.25-x

Putting values in expression 1, we get:

$4=\frac{(0.25-x)(0.4-x)}{(0.1+x)(0.1+x)}\\\\3x^2+1.45x-0.06=0\\\\x=0.038,-0.522$

Neglecting the negative value of 'x'

Calculating the concentrations of the species:

Concentration of carbon dioxide = (0.4 - x) = (0.4 - 0.038) = 0.362 M

Concentration of hydrogen gas = (0.25 - x) = (0.25 - 0.038) = 0.212 M

Concentration of carbon monoxide = (0.1 + x) = (0.1 + 0.038) = 0.138 M

Concentration of water = (0.1 + x) = (0.1 + 0.038) = 0.138 M

Hence, the concentration of carbon dioxide, hydrogen gas, carbon monoxide and water when equilibrium is re-established are 0.362 M, 0.212 M, 0.138 M and 0.138 M respectively.

8 0

4 years ago

Calculate the density of an object with a mass of 3.8 g, that when placed in a 10.0 mL graduated cylinder with an initial volume

Arturiano [62]

Answer : The density of an object is 0.93 g/mL

Explanation : Given,

Mass of an object = 3.8 g

Initial volume = 4.5 mL

Final volume = 8.6 mL

First we have to calculate the volume of an object.

Volume of an object = Final volume - Initial volume

Volume of an object = 8.6 mL - 4.5 mL

Volume of an object = 4.1 mL

Now we have to calculate the density of an object.

Formula used:

$\text{Density}=\frac{\text{Mass of an object}}{\text{Volume of an object}}$

Now putting all the given values in this formula, we get:

$\text{Density}=\frac{3.8g}{4.1mL}$

$\text{Density}=0.93g/mL$

Therefore, the density of an object is 0.93 g/mL

3 0

3 years ago

Why can air pollution be a problem even if you do not live next to a factory?

Lilit [14]

Answer:

cause pollution on a small scale can make big difference......

Explanation:

factory isn't a single source of pollution

there are many more.....

6 0

3 years ago

When dynamic equilibrium is achieved, the rate of the forward and backward reactions go to zero. (T&F)

ratelena [41]

Answer:

1) False

2) there are equal amounts of rectants and products

Explanation:

1) When dynamic equilibrium is achieved. the rate of forward and backward reaction they are the same, that is to say, two opposite reactions occur at the same rate, keeping the concentrations constant over time. Different to say the rate of the ractions go to zero.

2) A chemical equilibium exists when what is produce in quantities is equal to what reacts.

So the correct answer is the literal (d).

5 0

3 years ago

A) How many electron pairs are on the central atom of an H2S molecule?

zlopas [31]

Answer:

Each Hydrogen atom has one only one electron which is also its valence electron and Sulfur has six valence electrons. Thus, there are a total of eight valence electrons in H2S. In this compound, both the hydrogen atoms require one electron to make the covalent bond with Sulfur

6 0

3 years ago