HELLLLP ITS 8TH GRADE SCIENCE AND DUE TODAY

How are carbon dioxide (CO2) levels in the atmosphere affected by tectonic uplift of rocks and their resultant chemical weatheri

valina [46]

Answer:

The levels of carbon dioxide (CO2) in the atmosphere are reduced

Explanation:

Tectonic uplift refers to the process by which the surface of the earth slowly rises either due to increasing upward force applied from the plates below the surface or decreasing downward force or weight of objects like melting glaciers acting from above. During uplift, land, as well as the sea floor rises forming mountains, plateaus and volcanic Islands.

During the process of weathering, carbon dioxide present in air combines with rainwater and forms carbonic acid. This acidic rainwater then falls on uplifted mountains and rocks weathering them in the process. Minerals present in the rock such as calcium, magnesium and sodium then combine with bicarbonate ions to form carbonates such as calcium carbonate, magnesium carbonate which are found in shells of living and dead organisms and also form rocks such as limestone. In this way, carbon dioxide is removed from the atmosphere.

7 0

3 years ago

Describe a method to calculate the average atomic mass of the sample in the previous question using only the atomic masses of li

alexira [117]

Answer:

Explanation:

To calculate their average atomic masses which is otherwise known as the relative atomic mass, we simply multiply the given abundances of the atoms and the given atomic masses.

The abundace is the proportion or percentage or fraction by which each of the isotopes of an element occurs in nature.

This can be expressed below:

RAM = Σmₙαₙ

where mₙ is the mass of isotope n

αₙ is the abundance of isotope n

for this problem:

RAM of Li = m₆α₆ + m₇α₇

m₆ is mass of isotope Li-6

α₆ is the abundance of isotope Li-6

m₇ is mass of isotope Li-7

α₇ is the abundance of isotope Li-7

3 0

3 years ago

Question: Draw a valid Lewis structure for the molecule CH3NO in which there are no nonzero formal charges on any of the atoms.

iVinArrow [24]

The mentioned molecule with formula, CH₃NO where no bond is found between N and O can be depicted as formamide is shown in the attachment below.

The formal charges = Number of valence electrons for the atom (V) - the number of electrons in lone pairs (N) - 1/2 (number of electrons in bond pairs, B)

FC = V - N - B/2

Thus, there is a need to calculate valence electrons, electrons in lone pairs, and the number of electrons in bond pairs for each atom in the mentioned molecule.

V or valence electrons on C = 4e, on H = 1e, on N = 5e, and on O = 6e.

N or electrons in lone pairs on C = 0e, on H = 0e, on N = 2e, and on O = 4e.

B or number of electrons in bond pairs for C = 8e, for H = 2e, for N = 6e, and for O = 4e.

Thus, the formal charges for each will be,

C = 4 - 0 - (8/2) = 0

H = 1 - 0 - (2/2) = 0

N = 5 - 2 - (6/2) = 0

O = 6 - 4 - (4/2) = 0

Lewis dot structure for the given molecule is given in the attachment below:

3 0

3 years ago

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Calculate the percent of each component in the mixture. Show your calculations. Circle final answers.

Colt1911 [192]

Answer:

See Explanation

Explanation:

The question is incomplete; as the mixtures are not given.

However, I'll give a general explanation on how to go about it and I'll also give an example.

The percentage of a component in a mixture is calculated as:

$\%C_E = \frac{E}{T} * 100\%$

Where

E = Amount of element/component

T = Amount of all elements/components

Take for instance:

In $(Ca(OH)_2)$

The amount of all elements is: (i.e formula mass of $(Ca(OH)_2)$ )

$T = 1 * Ca + 2 * H + 2 * O$

$T = 1 * 40 + 2 * 1 + 2 * 16$

$T = 74$

The amount of calcium is: (i.e formula mass of calcium)

$E = 1 * Ca$

$E = 1 * 40$

$E = 40$

So, the percentage component of calcium is:

$\%C_E = \frac{E}{T} * 100\%$

$\%C_E = \frac{40}{74} * 100\%$

$\%C_E = \frac{4000}{74}\%$

$\%C_E = 54.05\%$

The amount of hydrogen is:

$E = 2 * H$

$E = 2 * 1$

$E = 2$

So, the percentage component of hydrogen is:

$\%C_E = \frac{E}{T} * 100\%$

$\%C_E = \frac{2}{74} * 100\%$

$\%C_E = \frac{200}{74}\%$

$\%C_E = 2.70\%$

Similarly, for oxygen:

The amount of oxygen is:

$E = 2 * O$

$E = 2 * 16$

$E = 32$

So, the percentage component of oxygen is:

$\%C_E = \frac{E}{T} * 100\%$

$\%C_E = \frac{32}{74} * 100\%$

$\%C_E = \frac{3200}{74}\%$

$\%C_E = 43.24\%$

5 0

3 years ago

Why does hot water freeze faster than cold water?

weeeeeb [17]

<h2>Answer:</h2>

<u>Temperature dependency is responsible for the process that hot water freeze faster than cold water.</u>

<h2>Explanation:</h2>

The effect given above is called Mpemba Effect. According to this idea hot water freezes more quickly as compared to cold water. But until now there is no convincing explanation for this strange phenomenon. One idea is that hot containers make better thermal contact with a refrigerator and so conduct heat more efficiently because a good conductor is good fro the transfer of heat. Another idea about this effect is that warm water evaporates more quickly and since this is an endothermic process, it cools the water making it freeze more quickly.

7 0

3 years ago

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