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3 years ago

Write your own example of how the carbon cycle works.

Chemistry

2 answers:

bulgar [2K]3 years ago

7 0

Answer:

Under the picture

Explanation:

Dmitrij [34]3 years ago

4 0

Answer:

Carbon moves from fossil fuels to the atmosphere when fuels are burned

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Helpe pls I will mark brainlest

olya-2409 [2.1K]

Answer:

What is the question needing to be answered?

Explanation:

Usually with a scientific hypothesis, you ask the question in an if, then statement. For example: If it rains outside, then the ground will be wet. It's kind of like a cause and effect statement.

4 0

3 years ago

A 32.14 gram sample of a hydrate of MnSO4 was heated thoroughly in a porcelain crucible, until its weight remained constant. Aft

amid [387]

Answer:

MnSO₄.7H₂O

Explanation:

To solve this question, we need to convert the mass of the dehydrated MnSO₄. The difference between mass of the hydrate and dehydrated compound is the mass of water. With the mass we can find the moles of water and the formula of the hydrate:

<em>Moles MnSO₄ -Molar mass: 151g/mol-:</em>

17.51g * (1mol / 151g) = 0.116 moles

<em>Moles H₂O -Molar mass: 18g/mol-:</em>

32.14g-17.51g = 14.63g * (1mol / 18g) = 0.813 moles

The ratio of moles MnSO₄: Moles H₂O represent the amount of water molecules in the hydrate:

0.813mol / 0.116mol = 7 molecules of water.

The hydrate formula is:

8 0

3 years ago

What is true of neutrons?

Marrrta [24]

Neutron, neutral subatomic particle that is a constituent of every atomic nucleus except ordinary hydrogen. It has no electric charge and a rest mass equal to 1.67493 × 10−27 kg—marginally greater than that of the proton but nearly 1,839 times greater than that of the electron.

7 0

3 years ago

Part A

KonstantinChe [14]

Answer:

The answer to your question is below

Explanation:

[H₃O⁺] = 2 x 10⁻¹⁴ M

pH = ?

Formula

pH = - log [H₃O⁺]

Substitution

pH = - log [2 x 10⁻¹⁴]

Result

pH = 13.7

[H₃O⁺] = ?

pH = 3.12

Formula

pH = - log [H₃O⁺]

Substitution

3.12 = - log [H₃O⁺]

$10^{-3.12} = [H_{3} O^{+}]$

Result

[H₃O⁺] = 7.59 M

7 0

3 years ago

The unit cell for cr2o3 has hexagonal symmetry with lattice parameters a = 0.4961 nm and c = 1.360 nm. If the density of this ma

IRINA_888 [86]

To calculate the packing factor, first calculate the area and volume of unit cell.

Area is calculated as:

$A=6R^{2}\sqrt{3}$

Here, R is radius and is related to a as follows:

$R=\frac{a}{2}$

Putting the value in expression for area,

$A=6(\frac{a}{2})^{2}\sqrt{3}=1.5a^{2}\sqrt{3}$

The value of a is 0.4961 nm

Since, $1 nm=10^{-7}cm$

Thus, $0.4961 nm=4.961\times 10^{-8} cm$

Putting the value,

$Area=1.5(4.961\times 10^{-8}cm)^{2}\sqrt{3}=6.39\times 10^{-15}cm^{2}$

Now, volume can be calculated as follows:

$V=Area\times c$

The value of c is 1.360 nm or $1.360\times 10^{-7} cm$

Putting the value,

$V=(6.39\times 10^{-15}cm^{2})\times (1.360\times 10^{-7} cm)=8.7\times 10^{-22}cm^{3}$

now, number of atom in unit cell can be calculated by using the following formula:

$n=\frac{\rho N_{A}V_{c}}{A}$

Here, A is atomic mass of $Cr_{2}O_{3}$ is 151.99 g/mol.

Putting all the values,

$n=\frac{(5.22 g/cm^{3})(6.023\times 10^{23} mol^{-1})(8.7\times 10^{-22}cm^{3})}{(151.99 g/mol)}\approx 18$

Thus, there will be 18 $Cr_{2}O_{3}$ units in 1 unit cell.

Since, there are 2 Cr atoms and 3 oxygen atoms thus, units of chromium and oxygen will be 2×18=36 and 3×18=54 respectively.

The atomic radii of $Cr^{3+}$ and $O^{2-}$ is 62 pm and 140 pm respectively.

Converting them into cm:

$1 pm=10^{-10}cm$

Thus,

$r_{Cr^{3+}}=6.2\times 10^{-9}cm$

and,

$r_{O^{2-}}=1.4\times 10^{-8}cm$

Volume of sphere will be sum of volume of total number of cations and anions thus,

$V_{S}=V_{Cr^{3+}}+V_{O^{2-}}$

Since, volume of sphere is $V=\frac{4}{3}\pi r^{3}$ ,

$V_{S}=36\left ( \frac{4}{3}\pi (r_{Cr^{3+})^{3}} \right )+54\left ( \frac{4}{3}\pi (r_{O^{2-})^{3}} \right )$

Putting the values,

$V_{S}=36\left ( \frac{4}{3}(3.14) (6.2\times 10^{-9} cm)^{3}} \right )+54\left ( \frac{4}{3}(3.14) (1.4\times 10^{-8} cm)^{3}} \right )=6.6\times 10^{-22}\times 10^{-8}cm^{3}$

The atomic packing factor is ratio of volume of sphere and volume of crystal, thus,

$packing factor=\frac{V_{S}}{V_{C}}=\frac{6.6\times 10^{-22}cm^{3}}{8.7\times 10^{-22}cm^{3}}=0.758$

Thus, atomic packing factor is 0.758.

6 0

3 years ago

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