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ddd [48]
2 years ago
7

Calculate the number of moles of iodine in 7.68×10^25 molecules of I2

Chemistry
1 answer:
Dmitrij [34]2 years ago
4 0

Answer:

<h2>127.57 moles</h2>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

n =  \frac{N}{L} \\

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

n =  \frac{7.68 \times  {10}^{25} }{6.02 \times  {10}^{23} }   \\  = 127.574750...

We have the final answer as

<h3>127.57 moles</h3>

Hope this helps you

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Answer:

A. 32.06 g/mol

Explanation:

The molar mass units are always g/mol

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If 42.7 of 0.208 M hydrochloric acid are needed to completely neutralize a solution of calcium hydroxide, how many grams of calc
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Answer:

0.329 g

Explanation:

In the context of this problem, we have a chemical reaction between hydrochloric acid and calcium hydroxide. HCl is the acid here and calcium hydroxide is the base. Hence, we have an acid-base reaction, also known as neutralization reaction.

In a neutralization reaction, water is produced as a product, as well as a salt that we obtain after we exchange the cations: calcium bonds to chloride and hydrogen bonds to hydroxide (the latter is the formation of water). This means we also produce calcium chloride as a product. The overall reaction represents this as:

Ca(OH)_2(aq)+2 HCl (aq)\rightarrow CaCl_2 (aq)+2 H_2O (l)

Firslt of all, we wish to find the number of moles of HCl present. Having molarity and volume, this is done by applying the molarity formula. It states that molarity is equal to the rate between moles and volume:

c_{HCl}=\frac{n_{HCl}}{V_{HCl}}

Rearranging for moles of HCl, n:

n_{HCl}=c_{HCl}V_{HCl}

Based on stoichiometry of the balanced chemical equation, notice that 1 mole of calcium hydroxide reacts with 2 moles of HCl, meaning:

n_{Ca(OH)_2}=\frac{1}{2} n_{HCl}=\frac{1}{2}c_{HCl}V_{HCl}

Now that we have the expression for moles, we may also express moles of calcium hydroxide as the ratio between its mass and molar mass:

n_{Ca(OH)_2}=\frac{m_{Ca(OH)_2}}{M_{Ca(OH)_2}}

Using the last two equations, we see that:

\frac{1}{2}c_{HCl}V_{HCl}=\frac{m_{Ca(OH)_2}}{M_{Ca(OH)_2}}\\\therefore m_{Ca(OH)_2}=\frac{1}{2}c_{HCl}V_{HCl}M_{Ca(OH)_2}

Substitute the given data, as well as the molar mass of calcium hydroxide:

m_{Ca(OH)_2}=\frac{1}{2}\cdot0.208 M\cdot0.0427 L\cdot74.093 g/mol=0.329 g

8 0
3 years ago
Where does the water in air come from?
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Answer:

About 90 percent of water in the atmosphere is produced by evaporation from water bodies, while the other 10 percent comes from transpiration from plants. There is always water in the atmosphere.✌️

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If the Moon rises at 7 P.M. on a particular day, then approximately what time will it rise six days later?
OLga [1]

Answer:

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During chemical weathering, forsterite is dissolved by the carbonic acid in rainwater. The weathering reaction is as follows:
Semenov [28]

Answer:

Keqq = 310

Note: Some parts of the question were missing. The missing values are used in the explanation below.

Explanation:

<em>Given values: ΔH° = -178.8 kJ/mol = -178800 J/mol; T = 25°C = 298.15 K; ΔS° = -552 J/mol.K; R = 8.3145 J/mol.K</em>

Using the formula ΔG° = -RT㏑Keq

㏑Keq = ΔG°/(-RT)

where ΔG° = ΔH° - TΔS°

㏑Keq = ΔH° - TΔS°/(-RT)

㏑Keq = {-178800 - (-552 * 298.15)} / -(8.3145 * 298.15)

㏑Keq = -14221.2/-2478.968175

㏑Keq = 5.73674166

Keq = e⁵°⁷³⁶⁷⁴¹⁶⁶

Keq = 310.05

4 0
3 years ago
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