Why does fullerene has a lower melting point than diamond?

sammy [17]

Answer:

Richard Nixon was elected the 37th President of the United States (1969-1974) after previously serving as a U.S. Representative and a U.S. Senator from California.

Explanation:

3 0

2 years ago

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How many molecules of water can be produced from 46.72 liters of C8H18? 2\:C_8H_{18}\:+\:25\:O_2\:\:\Longrightarrow\:\:16\:CO_2\

Dmitry [639]

Answer:

1.13×10^25 molecules of water.

Explanation:

Equation of the reaction;

C8H18(g) + 25/2 O2 (g) -------> 8CO2(g) + 9H2O(l)

It is important to first put down the balanced reaction equation. It is not possible to solve any problem on stoichiometric relationship without a balanced reaction equation. Once the equation is obtained, we can now proceed with other steps in the solution of the problem.

From the reaction equation, 1 mole of C8H18 produces 9 moles of water

1 mole of C8H18 occupies 22.4L volume while 1 mole of water contains 6.02×10^23 molecules of water

Hence

22.4 L of C8H18 produces 9(6.02×10^23) molecules of water

46.72 L of C8H18 will produce 46.72 L × 9(6.02×10^23) molecules of water/22.4 L

= 113×10^23 or 1.13×10^25 molecules of water.

5 0

3 years ago

For each of the following balanced chemical equations, calculate how many moles and how many grams of each product would be prod

natima [27]

Answer:

(a)

Moles of ammonium chloride = 0.5 mole

Mass of ammonium chloride formed = 26.7455 g

(b)

Mole of $CS_2$ = 0.125 mole

Mass = Moles * Molar mass = 0.125 * 76.139 g = 9.52 g

Mole of $H_2S$ = 0.25 mole

Mass = Moles * Molar mass = 0.25 * 34.1 g = 8.525 g

Explanation:

(a)

For the first reaction:-

$NH_3_{(g)}+HCl_{(g)}\rightarrow NH_4Cl_{(s)}$

The mole ratio of the reactants = 1 : 1

0.5 moles of ammonia react with 0.5 moles of hydrochloric gas to give 0.5 moles of ammonium chloride

So, Moles of ammonium chloride formed = 0.5 moles

Molar mass of ammonium chloride = 53.491 g/mol

Mass = Moles * Molar mass = 0.5 * 53.491 g = 26.7455 g

(b)

For the first reaction:-

$CH_4_{(g)}+4S_{(s)}\rightarrow CS_2_{(l)}+2H_2S_{(g)}$

The mole ratio of the reactants = 1 : 4

It means

0.5 moles of methane react with 2.0 moles of sulfur to give 0.5 moles of Carbon disulfide and 1.0 moles of hydrogen sulfide gas.

But available moles of S = 0.5 moles

Limiting reagent is the one which is present in small amount. Thus, S is limiting reagent.

The formation of the product is governed by the limiting reagent. So,

4 moles of S produces 1 mole of $CS_2$

Thus,

0.5 moles of S produces $\frac{1}{4}\times 0.5$ mole of $CS_2$

Mole of $CS_2$ = 0.125 mole

Molar mass of $CS_2$ = 76.139 g/mol

Mass = Moles * Molar mass = 0.125 * 76.139 g = 9.52 g

4 moles of S produces 2 moles of $H_2S$

Thus,

0.5 moles of S produces $\frac{2}{4}\times 0.5$ mole of $H_2S$

Mole of $H_2S$ = 0.25 mole

Molar mass of $H_2S$ = 34.1 g/mol

Mass = Moles * Molar mass = 0.25 * 34.1 g = 8.525 g

7 0

2 years ago

If the enthalpy change of a reaction in a flask is δh = +67 kj, what can be said about the reaction?

ziro4ka [17]

Answer : Normally in any chemical reaction, if the enthalpy change i.e. ΔH is positive which means it is greater than zero then it can be called as an Endothermic Reaction.

Whereas, the system under study is absorbing heat that is produced during the reaction. So if ΔH is found to be positive then it can be called as endothermic reaction.

3 0

3 years ago

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A compound decomposes by a first-order process. if 25.0% of the compound decomposes in 60.0 minutes, the half-life of the compou

Tom [10]

Answer:d. 145 minutes

Half-life is the time needed for a radioactive to decay half of its weight. The formula to find the half-life would be:

Nt= N0 (1/2)^ t/h

Nt= the final mass
N0= the initial mass
t= time passed
h= half-life

If 25.0% of the compound decomposes that means the final mass would be 75% of initial mass. Then the half-live for the compound would be:
Nt= N0 (1/2)^ t/h
75%= 100% * (1/2)^ (60min/h)
3/4= 1/2^(60min/h)
log2 3/4 = log2 1/2^(60min/h)
0.41503749928 = -60min/h
h= -60 min / 0.41503749928= 144.6min

3 0

3 years ago