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3 years ago

What are the four important steps needed to obtain accurate melting points on a mel-temp

Chemistry

1 answer:

AveGali [126]3 years ago

3 0

Explanation:

1) refine the specimen into fine powder 2) place the smallest amount you can see in the capillary tube 3) set the voltage to increase exponentially to 200 below the predicted temperature, then adjust so that the temperature rises to 20 per minute 4) report the temperature at which the liquid first appears and the temperature at which the last crystal disappears.

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Methane and chlorine react to form four products: CH3Cl, CH2Cl2, CHCl3, and CCl4. At a particular temperature and pressure, 38.4

Anastasy [175]

Answer:

How many grams of CCL4 were formed? 116.9 g

How many grams of Cl2 reacted with the CH4? 243.8 g

Explanation:

First we need to know the molar mass for every element or compound in the reaction:

$M_{CH_{4}}=16 g/mol\\M_{CH_{3}Cl}=50.49g/mol\\M_{CH_{2}Cl_{2}}=84.93g/mol\\M_{CHCl_{3}}=119.38g/mol\\M_{CCl_{4}}=153.82g/mol$

Now we proceed to calculate the amount of moles produced, per product:

$n_{CH_{4}}=2.4\\n_{CH_{3}Cl}=0.18\\n_{CH_{2}Cl_{2}}=0.55\\n_{CHCl_{3}}=0.91\\n_{CCl_{4}}=n_{CH_{4}}-(n_{CH_{3}Cl}+n_{CH_{2}Cl_{2}}+n_{CHCl_{3}})\\n_{CCl_{4}}=0.76mol\\m_{CCl_{4}}=n_{CCl_{4}}*M_{CCl_{4}}\\m_{CCl_{4}}=116.9g$

To calculate the mass of chlorine we just need to make a mass balance:

$m_{CH_{4}}+m_{Cl_{2}}=m_{CH_{3}Cl}+m_{CH_{2}Cl_{2}}+m_{CHCl_{3}}+m_{CCl_{4}}\\m_{Cl_{2}}=m_{CH_{3}Cl}+m_{CH_{2}Cl_{2}}+m_{CHCl_{3}}+m_{CCl_{4}}-m_{CH_{4}}\\m_{Cl_{2}}=243.8g$

3 0

3 years ago

20. A compound's empirical formula is C5H5O If the molecular mass of the compound is

MA_775_DIABLO [31]

Answer:

Just use a text book.. So that you get the concept

8 0

3 years ago

Reduction and oxidation must occur together. The electrons from the oxidized species are transferred to the reduced species. Che

Aneli [31]

Explanation:

When a specie tends to lose electrons in a chemical reaction then it means oxidation has taken place. When a specie tends to gain electrons then it means reduction has taken place.

So, for the given reactions the value of $E_{o}$ are as follows.

$Zn^{2+} + 2e^{-} \rightarow Zn$ , $E_{o} = -0.76 V$

$Cu^{2+} + 2e^{-} \rightarow Cu$ , $E_{o} = 0.34 V$

$\Delta G^{o} = -nFE^{o}_{cell}$

(a) Therefore, according to the given reactions the process is reduction.

(b) Here, n = 2

So, value of $Zn^{2+}$ is as follows.

$\Delta G^{o}_{Zn^{2+}} = -2 \times (-0.76) \times 96500$

= +146680 V

$\Delta G^{o}_{Cu^{2+}} = -2 \times (-0.34) \times 96500$

= -65620 V

(c) As per the calculated values, $Zn^{2+}$ is the best reducing agent and $Cu^{2+}$ is the best oxidizing agent.

Also, more positive is the $E_{o}$ value more good it acts as an oxidizing agent. Hence, it is able to favor reduction.

Therefore, $Cu^{2+}$ will more strongly favor reduction.

7 0

3 years ago

Finalmente responde:

dexar [7]

El agua se purifica a partir de un proceso de filtrado. Las características que evidencian el filtrado incluyen pH normal, color cristalino, ausencia de metales pesados y/o microorganismos, etc.

Los filtros para purificar agua son dispositivos que permiten el limpiado del agua con el objetivo de convertirla apta para consumo humano.

En general, los filtros para lograr la purificación del agua consisten de carbón activado, el cual se prensa con alta presión.

Este dispositivo de carbón activado permite secuestrar las partículas sólidas que pasan a través del filtro, con lo cual el agua sale a través del filtro completamente purificada.

Las características que permiten determinar si el agua ha sido correctamente filtrada incluyen:

El agua sale cristalina, es decir, sin ningún tipo de color que evidencie la presencia de contaminación.
El pH del agua potable debe oscilar entre valores normales (6,5 a 8,5)
No debe contener metales tales como plomo, arsénico o cadmio (altamente tóxicos)
No debe contener microorganismos

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8 0

3 years ago

What is Ky for CH3NH2(aq) + H20(1) = CH3NH3(aq) + OH(aq)?

zalisa [80]

I do not have any clue

6 0

3 years ago