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katovenus [111]
3 years ago
14

Methanol (CH3OH) has a heat of fusion of 3.16 kJ/mol. Which of the following is the heat of solidification that occurs when 64 g

rams of liquid methanol freezes?
-199 kJ
-6.32 kJ
199 kJ
6.32 kJ
Chemistry
2 answers:
Alexandra [31]3 years ago
5 0
To determine the heat dissipated when a substance freezes, we multiply the heat of fusion of the substance to the mass of the substance that freezes. We calculate as follows:

Heat = -3.16 (64/32.06) = - 6.32 kJ

Hope this answers the question.
nignag [31]3 years ago
3 0

Answer : The correct option is, -6.32 KJ

Solution : Given,

Mass of methanol = 64 g

Molar mass of methanol = 32 g/mole

Heat of fusion = 3.16 KJ/mole

First we have to calculate the moles of methanol.

\text{Moles of methanol}=\frac{\text{Mass of methanol}}{\text{Molar mass of methanol}}=\frac{64g}{32g/mole}=2mole

Moles of methanol = 2 moles

Now we have to calculate the heat of solidification.

As, 1 mole of methanol contains heat = 3.16 KJ

So, 2 mole of methanol contains heat = 2\times 3.16KJ=6.32KJ

The heat of solidification is, -6.32 KJ. The negative sign indicate the heat released in the system.

Therefore, the heat of solidification is, -6.32 KJ

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kakasveta [241]

Answer:

Explanation:

The given reaction is exothermic . So ΔH is negative .

Gas is evolving so work done by gas is positive or w is positive.

Change in internal energy that is ΔU is negative.

q = u - w

u is negative , w is positive so q is negative .

4 0
3 years ago
An ore is to be analyzed for its iron content by an oxidation-reduction titration with permanganate ion. A 4.230 g sample of the
Leya [2.2K]

Answer:

See explanation

Explanation:

The balanced redox reaction equation is;

8H+ + MnO4^- + 5Fe2+ ---------> Mn2+ + 5Fe3+ + 4H2O

Amount of KMnO4 reacted = 31.60/1000 * 0.05120 = 1.62 * 10^-3 moles

From the reaction equation;

1 mole of MnO4^- reacted with 5 moles of Fe2+

1.62 * 10^-3 moles will react with 1.62 * 10^-3 moles * 5/1 = 8.1 * 10^-3 moles

Mass of Fe2+ reacted = 8.1 * 10^-3 moles  *  56 g/mol

Mass of Fe2+ reacted = 0.45 g

Amount of iron in the sample =  0.45 g

Percentage of iron in the sample;

0.45 g/4.230 g  * 100 = 10.6 %

8 0
2 years ago
If 12.4 mol of Ne gas occupies 122.8 L, how many mol of Ne would occupy 339.2 L under the same temperature and pressure? Record
8090 [49]

Answer:

3.43×10¹ mol

Explanation:

Given data:

Initial number of  moles = 12.4 mol

Initial volume = 122.8 L

Final number of moles = ?

Final volume = 339.2 L

Solution:

The number of moles and volume are directly proportional to each other at same temperature and pressure.

V₁/n₁  =  V₂/n₂

122.8 L/ 12.4 mol  =  339.2 L / n₂

n₂ = 339.2 L× 12.4 mol  / 122.8 L

n₂ = 4206.08 L.mol /122.8 L

n₂ = 34.3mol

In scientific notation:

3.43×10¹ mol

7 0
2 years ago
Please help I will give brainliest.
iris [78.8K]

Answer:

the second one looks like it so I picked the second one

8 0
3 years ago
2SO3(g)⟶2S(s)+3O2(g)ΔH=+790kJ. How many kilojoules are required when 2.1 moles of SO3 reacts?
guapka [62]

<u>Given:</u>

Enthalpy change (ΔH) for SO3 decomposition = +790 kJ

Moles of SO3 = 2.1 moles

<u>To determine:</u>

Energy required when 2.1 moles of SO3 reacts

<u>Explanation:</u>

The decomposition reaction is -

2SO3(g) → 2S(s) + 3O2 (g)

Energy required when 2 moles of SO3 reacts is 790 kJ

Thus, for 2.1 moles of SO3 the energy requirement would be

= 2.1 moles SO3 * 790 kJ/2 moles SO3 = 829.5 kJ

Ans: 830 kJ are required when 2.1 moles of SO3 reacts.

4 0
2 years ago
Read 2 more answers
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