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LenKa [72]
3 years ago
12

The molar heat of vaporization of hydrogen fluoride (HF) is 31.18 kJ/mol. How much heat is released when 100.0 g HF condenses at

its boiling point?
Chemistry
2 answers:
mash [69]3 years ago
8 0

the answer is -155.8


OLga [1]3 years ago
6 0

<u>Answer:</u> The amount of heat released is 155.9 kJ

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}

We are given:

Given mass of HF = 100.0 g

Molar mass of HF = 20 g/mol

Putting values in above equation, we get:

\text{Moles of HF}=\frac{100.0g}{20g/mol}=5mol

To calculate the heat of the reaction, we use the equation:

\Delta H_{rxn}=\frac{q}{n}

where,

q = amount of heat released =

n = number of moles = 5 moles

\Delta H_{rxn} = enthalpy change of the reaction = 31.18 kJ/mol

Putting values in above equation, we get:

31.18kJ/mol=\frac{q}{5mol}\\\\q=(31.18kJ/mol\times 5mol)=155.9kJ

Hence, the amount of heat released is 155.9 kJ

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Additive color mixing involves multiple sources of light with different colors in each source. Subtractive color mixing involves a single source of light with different colors absorbing various wavelengths of the color spectrum. Secondary colors of one system serve as the primary colors for the other.
8 0
2 years ago
You wish to prepare a buffer consisting of acetic acid and sodium acetate with a total acetic acetate plus acetate concentration
vovangra [49]

<u>Ans: Acetic acid = 90.3 mM and Sodium acetate = 160 mM</u>

Given:

Acetic Acid/Sodium Acetate buffer of pH = 5.0

Let HA = acetic acid

A- = sodium acetate

Total concentration [HA] + [A-] = 250 mM ------(1)

pKa(acetic acid) = 4.75

Based on Henderson-Hasselbalch equation

pH = pKa + log[A-]/[HA]

[A-]/[HA] = 10^(pH-pKa) = 10^(5-4.75) = 10^0.25 = 1.77

[A-] = 1.77[HA] -----(2)

From (1) and (2)

[HA] + 1.77[HA] = 250 mM

[HA] = 250/2.77 = 90.25 mM

[A-] = 1.77(90.25) = 159.74 mM



7 0
3 years ago
What is the density of a liquid if it's volume is 125 mL and it's mass is 50g?
masha68 [24]

Answer:

0.4g/ml

Explanation:

density= mass/volume

density=50g/125ml

density=0.4g/ml

6 0
2 years ago
Calculate the ph of the solution resulting by mixing 20.0 ml of 0.15 m hcl with 20.0 ml of 0.10 m koh
Aliun [14]

Answer:

1.60.

Explanation:

  • The no. of millimoles of HCl = MV = (0.15 M)(20.0 mL) = 3.0 mmol.
  • The no. of millimoles of KOH = MV = (0.10 M)(20.0 mL) = 2.0 mmol.

<em>Since the no. of millimoles of HCl is larger than that of KOH. The solution is acidic.</em>

<em></em>

∴ M of remaining HCl [H⁺] remaining = (NV)HCl - (NV)KOH/V total = (3.0 mmol) - (2.0 mmol) / (40.0 mL) = 0.025 M.

∵ pH = - log[H⁺]

<em>∴ pH = - log[H⁺] </em>= - log(0.025) = <em>1.602 ≅ 1.60.</em>

5 0
3 years ago
What substance is reduced in the reaction 2Fe 2+ + CI2 = 2Fe 3+ + 2CI- ?
atroni [7]

Answer:

$Cl_{2}$ is reduced in the reaction

Explanation:

The given reaction is

$2Fe^{2+}+Cl_{2} \to 2Fe^{3+}+2Cl^{-}$

The oxidation number of $Fe$ is changed from $+2\, \to \, +3$

$Fe^{2+} \to Fe^{3+}+e^{-}$

And The oxidation number of $Cl$ is changed from $0\, \to \, -1$

$Cl_{2}^{0} + 2e^{-} \to 2Cl^{-}$

Hence, $Fe^{2+}$ is oxidized and $Cl_{2}$ is reduced

5 0
3 years ago
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