The number of _____ determines which element it is.

Hydrogen reacts with chlorine to form hydrogen chloride (HCl (g), mc012-1.jpgHf = –92.3 kJ/mol) according to the reaction below.

Kobotan [32]

Given:

H2(g) + Cl2 (g) → 2HCl (g)

To determine:

The enthalpy of the reaction and whether it is endo or exothermic

Explanation:

Enthalpy of a reaction is given by the difference between the enthalpy of formation of reactants and products

ΔH = ∑nHf (products) - ∑nHf (reactants)

= [2Hf(HCl)] - [Hf(H2) + Hf(Cl2)] = 2 (-92.3) kJ = - 184.6 kJ

Since the reaction enthalpy is negative, the reaction is exothermic

Ans: The enthalpy of reaction is -184. kJ and the reaction is exothermic

3 0

2 years ago

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What pressure (in atmospheres) does a gas exert when at 385 mm of Hg?

Westkost [7]

To find out the pressure in atm. You must divide 385 by 760. So pressure in atmospheres equals 385/760.

6 0

3 years ago

The decomposition of SOCl2 is first-order in SOCl2. If the half-life for the reaction is 4.1 hr, how long would it take for the

qaws [65]

4.1 h = 14760 s

t 1/2 = ln 2 / k 

k = rate reaction = 4.97 x 10^-5 

ln 0.045 / 0.36 = - 4.97 x 10^-5 t 

2.08 = 4.97 x 10^-5 t 

t = 41839.9 s = 11 h 37 min 19 s

3 0

2 years ago

A tablet of Pain Be Gone Aspirin, which had a mass of 1.213 g, was pulverized and 1.159 g were dissolved in 10.0 mL of ethyl alc

Elan Coil [88]

Answer:

a. Moles of $NaOH$ = 0.001643 moles

b. 0.296 g

c. 0.3098 g

d. Not acceptable

Explanation:

a.

Considering:

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

Or,

$Moles =Molarity \times {Volume\ of\ the\ solution}$

Given :

For $NaOH$ :

Molarity = 0.1052 M

Volume = 15.62 mL

The conversion of mL to L is shown below:

1 mL = 10⁻³ L

Thus, volume = 15.62×10⁻³ L

Thus, moles of $NaOH$ :

$Moles=0.1052 \times {15.62\times 10^{-3}}\ moles$

Moles of $NaOH$ = 0.001643 moles

b.

The reaction of NaOH with the acetylsalicylic acid is in the ratio of 1:1.

Thus, Moles of NaOH = Moles of acetylsalicylic acid = 0.001643 moles

Molar mass of acetylsalicylic acid = 180.16 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

Mass = Moles * Molar mass = 0.001643 moles * 180.16 g/mol = 0.296 g

c.

1.159 g of sample contains 0.296 g of acetylsalicylic acid

1.213 g of sample contains $\frac{0.296}{1.159}\times 1.213$ g of acetylsalicylic acid

Mass of acetylsalicylic acid = 0.3098 g = 309.8 mg

d. Sample contains = 309.8 mg

Manufacturer claiming = 315 mg to 335 mg

Thus , it is not acceptable.

5 0

2 years ago

True or False

goldenfox [79]

Answer:

I believe its True

4 0

2 years ago

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