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3 years ago

- 20 points.

Chemistry

1 answer:

JulijaS [17]3 years ago

4 0

A reaction, such as this one, starts with a reactant. It needs to have activation energy in order to change to the product, as shown by the hump in the graph. At the top of the hump is the transition state. This is the point where, after enough energy, the reactant will turn into the product. This reaction is exothermic. Since the product has less energy than the reactant, it had to have released energy somehow, and that energy was released in the form of heat, which makes it exothermic. (Exothermic reactions release heat, vs. endothermic reactions which absorb heat).

Bonus: a catalyst can be used to lower the activation energy by giving the reaction a “kick start,” requiring less energy in the reaction for the reactant to turn into the product.

-Lemme know if I can do anything else!

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Rank the members of each set of compounds in order of decreasing ionic character of their bonds. Use partial charges to indicate

Firdavs [7]

Answer:

Ionic character

A. PF₃ > PBr₃ > PCl₃

B. BF₃ > CF₄ > NF₃

C. TeF₄ > BrF₃ > SeF₄

Explanation:

The most electronegative element is fluorine, followed chlorine, phosphorous nitrogen etc.

Atoms with high electronegativity tend to form negative ions.

Ionic compounds formed between elements with high electronegativity difference.

% ionic character is directly proportional to electronegativity difference.
According to Pauling Scale E.n for F(4.0), O(3.5), N(3.0), C(2.5), B(2.0), P(2.19), Se(2.55) , Te (2.1), Cl(3.16) and Br(2.96)
ΔE.N (Electronegativity difference) between( P and F = 4 - 2.19 = 1.81), (P and Br = 2.96 - 2.19 = 0.77) , (P and Cl = 3.16 - 2.96 = 0.2 )

ΔE.N (Electronegativity difference) between( N and F = 4 - 3 = 1), (B and F = 4 - 2 = 2) , (C and F = 4 - 2.5 = 1.5 )

ΔE.N (Electronegativity difference) between( Se and F = 4 - 2.55 = 1.45), (F and Te = 4 - 2.1 = 1.9) , (F and Br = 4 - 2.19 = 1.81 )

6 0

3 years ago

Calculate the solubility of hydrogen in water at an atmospheric pressure of 0.380 atm (a typical value at high altitude).

Pani-rosa [81]

The question is incomplete, here is the complete question:

Calculate the solubility of hydrogen in water at an atmospheric pressure of 0.380 atm (a typical value at high altitude).

Atmospheric Gas Mole Fraction kH mol/(L*atm)

$N_2$ $7.81\times 10^{-1}$ $6.70\times 10^{-4}$

$O_2$ $2.10\times 10^{-1}$ $1.30\times 10^{-3}$

Ar $9.34\times 10^{-3}$ $1.40\times 10^{-3}$

$CO_2$ $3.33\times 10^{-4}$ $3.50\times 10^{-2}$

$CH_4$ $2.00\times 10^{-6}$ $1.40\times 10^{-3}$

$H_2$ $5.00\times 10^{-7}$ $7.80\times 10^{-4}$

<u>Answer:</u> The solubility of hydrogen gas in water at given atmospheric pressure is $1.48\times 10^{-10}M$

<u>Explanation:</u>

To calculate the partial pressure of hydrogen gas, we use the equation given by Raoult's law, which is:

$p_{\text{hydrogen gas}}=p_T\times \chi_{\text{hydrogen gas}}$

where,

$p_A$ = partial pressure of hydrogen gas = ?

$p_T$ = total pressure = 0.380 atm

$\chi_A$ = mole fraction of hydrogen gas = $5.00\times 10^{-7}$

Putting values in above equation, we get:

$p_{\text{hydrogen gas}}=0.380\times 5.00\times 10^{-7}\\\\p_{\text{hydrogen gas}}=1.9\times 10^{-7}atm$

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_{H_2}=K_H\times p_{H_2}$

where,

$K_H$ = Henry's constant = $7.80\times 10^{-4}mol/L.atm$

$p_{H_2}$ = partial pressure of hydrogen gas = $1.9\times 10^{-7}atm$

Putting values in above equation, we get:

$C_{H_2}=7.80\times 10^{-4}mol/L.atm\times 1.9\times 10^{-7}atm\\\\C_{CO_2}=1.48\times 10^{-10}M$

Hence, the solubility of hydrogen gas in water at given atmospheric pressure is $1.48\times 10^{-10}M$

4 0

3 years ago

The percentage of keys you type correctly is A. accuracy B. correctness C. exactness D. precision WHO EVER GETS THIS EARNS BRAIN

e-lub [12.9K]

The answer is A: accuracy

5 0

1 year ago

Having done the experiment, explain briefly how the mass of zinc not equal the mass of lead gained (hint: the periodic table)

masya89 [10]

Answer:

Due to the difference in the relative atomic masses and therefore, the molecular masses of Zn and Pb, one mole of Zn is about 3.2 times lighter than one mole of Pb

Explanation:

From the periodic table, we have;

The atomic number of zinc, Zn = 30

The atomic mass of zinc, Zn = 65.38 amu

The molar mass of zinc, Zn = 65.38 g/mol

The atomic number of lead, Pb = 82

The atomic mass of lead, Pb = 207.2 amu

The molar mass of lead, Pb = 207.2 g/mol

Therefore, whereby equal number of moles of Zn is lost and Pb is gained, we have;

Mass of 1 mole of Zn = 65.38 grams

Therefore, 1 gram of Zn = 1/65.38 moles = 0.0153 moles

0.12 grams of Zn = 0.12×0.0153 = 0.00184 moles of Zn

Given that equal number of moles of Zn and Pb are involved in the reaction, the number of moles of Pb gained = 0.00184 moles

The mass of Pb gained = Number of moles of Pb gained × Molar mass of Pb

The mass of Pb gained = 0.00184 × 207.2 = 0.38 g ≈ 0.4 g.

Amount of Pb gained = 0.43 g ≈ 0.4 g

4 0

2 years ago

A sample of helium gas is in a sealed rigid container. What occurs as the temperature of the sample is increased

hammer [34]

The electrons will move more rapidly resulting in a higher pressure even at a consistent volume

3 0

3 years ago