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3 years ago

Calculate E and determine whether the process is endothermic or exothermic for the following cases:

Chemistry

2 answers:

jonny [76]3 years ago

8 0

Answer: a) E= -0.077KJ Exothermic

b) E= -22.1KJ Exothermic

Explanation:

a) change internal energy E = q+ w

Since q= 0.763KJ and w=-840j= -0.84KJ

E= 0.763kj - 0.84kj

E= -0.077KJ

The process is exothermic since it releases heat to the surrounding i.e E is negative.

b) q= - 66.1KJ negative because it's heat released to the surrounding

w= 44.0KJ work done on the system by the surrounding.

E= q+w

E= -66.1KJ + 44.0KJ

E= -22.1KJ

The process is exothermic because the value of E is negative.

Goodluck...

Afina-wow [57]3 years ago

4 0

Answer:a) ∆E=-0.077KJ (exothermic)

b) ∆E = 110KJ (endothermic)

Explanation:

a) ∆E = q + w

q= 0.763 KJ

w= -840J = -0.840 KJ

∆E = 0.763-0.840 = - 0.077KJ

Exothermic reaction are those reactions that proceeds with the release of heat to the surroundings and Energy is negative in exothermic processes.

b)/∆E = q+w

q= 66.1KJ, w=44KJ

∆E = 101KJ

And it is endothermic

When work is done on a system, the international energy increases.

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4 years ago

For a given reaction, ΔS = +106 J/mol ⋅ K, and the reaction is spontaneous at temperatures above the crossover temperature, 446

solniwko [45]

Answer: 47.276 kJ/mol

Explanation:

According to Gibb's equation:

$\Delta G=\Delta H-T\Delta S$

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3 years ago

What mass of CCl4 is required to prepare a 0.25 m solution using 115 g of hexane? (molar mass of ccl4 = 153.81 g/mol and molar m

natka813 [3]

4.42 g mass of CCl4 is required to prepare a 0.25 m solution using 115 g of hexane.

It's easy to find the molecular mass of a compound with these steps: Determine the molecular formula of the molecule. Use the periodic table to determine the atomic mass of each element in the molecule. Multiply each element's atomic mass by the number of atoms of that element in the molecule.

The molar mass of any compound can be found out by adding the relative atomic masses of each element present in that particular compound.

Hexane is an organic compound, a straight-chain alkane with six carbon atoms and has the molecular formula C₆H₁₄.

Therefore,

⇒ 0.115 g of Hexane x (0.25 mol CCl4/1 mol hexane) x (153.81 g of CCl4/1 mol CCl4) = 4.42g CCl4.

To learn more about CCL4 and Hexane here

brainly.com/question/15156642

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2 years ago

Sarah measures out 151 grams of SO2. How many moles is this? Express your answer to three significant figures.

Anna11 [10]

Answer:

$\boxed {\boxed {\sf 2.36 \ mol \ SO_2}}$

Explanation:

We are asked to convert grams to moles. We will use the molar mass and dimensional analysis to perform this conversion.

<h3>1. Molar Mass</h3>

The molar mass is the mass of 1 mole of a substance. These values are found on the Periodic Table because they are equivalent to the atomic masses, but the units are grams per mole instead.

We are given a mass of sulfur dioxide (SO₂). Look up the molar masses of the individual elements.

Sulfur (S): 32.07 g/mol
Oxygen (O): 15.999 g/mol

Notice that the formula of the compound contains a subscript. The subscript after O means there are 2 moles of oxygen in 1 mole of sulfur dioxide. We must multiply oxygen's molar mass before adding sulfur's.

O₂: 15.999 * 2 = 31.998 g/mol
SO₂= 32.07 + 31.998 = 64.068 g/mol

<h3>2. Convert Grams to Moles </h3>

Now we will use dimensional analysis to convert grams to moles. From the molar mass, we know there are 64.068 grams of sulfur dioxide per mole, so we can set up a ratio.

$\frac {64.068 \ g \ SO_2} {1 \ mol \ SO_2}$

We are converting 151 grams to moles, so we multiply by this value.

$151 \ g \ SO_2 *\frac {64.068 \ g \ SO_2} {1 \ mol \ SO_2}$

Flip the ratio so the units of grams of sulfur dioxide cancel.

$151 \ g \ SO_2 *\frac {1 \ mol \ SO_2}{64.068 \ g \ SO_2}$

$151 *\frac {1 \ mol \ SO_2}{64.068 }$

$\frac {151}{64.068 } \ mol \ SO_2$

$2.356870825 \ mol \ SO_2$

<h3>3. Round </h3>

The original measurement of grams (151) has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place. The 6 in the thousandth place tells us to round the 5 in the hundredth up to a 6.

$2.36 \ mol \ SO_2$

151 grams of sulfur dioxide is approximately <u>2.36 moles of sulfur dioxide.</u>

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3 years ago