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3 years ago

Several billion years ago, which gas was the least prevalent in the atmosphere?

1 answer:

7 0

The least prevalent gas in the atmosphere was oxygen several billion years ago. This is because it was only around 2.4-3 billion years ago when the first photosynthetic bacteria evolved, meaning they produce food from inorganic compounds such as carbon dioxide and water to produce glucose and oxygen. Oxygen is then released in the atmosphere and this is called <em>The Great Oxygenation Event</em>.

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What is climate? How does it differ from weather

ozzi

Weather refers to short term atmospheric conditions while climate is the weather of a specific region averaged over a long period of time. Climate change refers to long-term changes.

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3 years ago

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How many moles of Al would be produced from 20 moles of Al2O3?<br> 2Al2O3<br> -><br> 4A1 + 302

Evgesh-ka [11]

<h3>Answer:</h3>

$\displaystyle 40 \ mol \ Al$

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right<u> </u>

<u>Chemistry</u>

<u>Stoichiometry</u>

Using Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

[RxN - Balanced] 2Al₂O₃ → 4Al + 3O₂

[Given] 20 mol Al₂O₃

<u>Step 2: Identify Conversions</u>

[RxN] 2 mol Al₂O₃ → 4 mol Al

<u>Step 3: Stoich</u>

[DA] Set up: $\displaystyle 20 \ mol \ Al_2O_3(\frac{4 \ mol \ Al}{2 \ mol \ Al_2O_3})$
[DA] Multiply/Divide [Cancel out units]: $\displaystyle 40 \ mol \ Al$

<u>Step 4:Check</u>

<em>Follow sig fig rules and round. We are given 1 sig fig.</em>

Since our final answer already has 1 sig fig, there is no need to round.

4 0

2 years ago

a closed flask of air (0.250 L) contains 5.00 "puffs" of particles. The pressure probe on the flask reads 93 kPa. A student uses

Sergio039 [100]

Answer: New pressure inside the flask would be 148.8 kPa.

Explanation: The combined gas law equation is given by:

$PV=nRT$

As the flask is a closed flask, so the volume remains constant. Temperature is constant also.

So, the relation between pressure and number of moles becomes

$P=n\\or\\\frac{P}{n}=constant$

$\frac{P_1}{n_1}=\frac{P_2}{n_2}$

Initial conditions:

$P_1=93kPa\\n_1=5\text{ puffs}$

Final conditions: When additional 3 puffs of air is added

$P_2=?kPa\\n_2=8\text{ puffs}$

Putting the values, in above equation, we get

$\frac{93}{5}=\frac{P_2}{8}\\P_2=148.8kPa$

3 0

3 years ago

Chlorine can bond with fluorine to form CIF. Chlorine can also bond with lithium to form LiCI Which compound will have a greater

Sergio [31]

Answer: $ClF$ will have a greater partial charge.

Explanation:

A polar covalent bond is defined as the bond which is formed when there is a low difference of electronegativities between the atoms, thus resulting in charge difference. Example: $ClF$

Non-polar covalent bond is defined as the bond which is formed when there is no difference of electronegativities between the atoms and thus there is no charge difference. Example: $F_2$

Ionic bond is formed when there is complete transfer of electron from a highly electropositive metal to a highly electronegative non metal. The electronegative difference between the elements is high. The charges on cation and anion neutralise each other. Example: $LiCl$

Thus as $ClF$ will have greater partial charge.

5 0

3 years ago

What is natural selection help plz help

Mars2501 [29]

Answer:

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.

Explanation:

Hope this helps! Please consider marking brainliest! I hope you have an amazing day. Always remember, your smart and you got this! -Alycia :)

6 0

2 years ago

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