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4 years ago

Safety glasses are worn in the lab for

2 answers:

4 0

Safety glasses should be worn any time you are doing an experiment, especially one that involves chemicals or chemical reactions. They prevent chemicals or other materials from getting on or in your eye, and can prevent anything from mild discomfort to permanent blindness.

Some pairs of safety glasses have magnifying glasses on them, similar to bifocals. They can be used to more carefully examine something in an experiment.

alexdok [17]4 years ago

4 0

Protecting your eyes from chemicals

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These are three theorized causes of A) glacial melting. B) changing of the climate. C) high and low ocean tides. D) movement of

professor190 [17]

actually its D) movement of tectonic plates

8 0

3 years ago

4. Cuál es la aplicación de las reacciones de óxido-reducción en la vida diaria y en la industria?

12345 [234]

Answer:

Dentro de las aplicaciones de la óxido-reducción se pueden encontrar:

La obtención del aluminio a partir de la alúmina y la electrolisis.
La obtención de cloro, hidrógeno e hidróxido de sodio a partir del cloruro de sodio y la electrolisis.
La combustión interna de un motor a gasolina u otro combustible fósil.
Las termoeléctricas, las cuales para generar energía realizan combustión de carbón.
La galvanoplastia, donde para evitar la corrosión de un metal se recubre con otro metal más resistente, por ejemplo: el recubrimiento del acero con zinc.
La pilas o baterías de las cuales se obtiene energía química.

Explanation:

Como puedes ver en la respuesta, la óxido-reducción tiene diversas aplicaciones en la vida moderna, desde todos los tipos de combustión los cuales sirven para brindar energía o movilizarte, hasta todas las funciones que se le ha dado a la electrolisis y a la obtención de la energía por medios químicos, incluso se puede considerar una aplicación de la óxido-reducción la incorporación de antioxidantes en los alimentos, los cuales disminuyen la velocidad de descomposición de los mismos.

3 0

3 years ago

You mix 200. mL of 0.400M HCl with 200. mL of 0.400M NaOH in a coffee cup calorimeter. The temperature of the solution goes from

GuDViN [60]

Answer : The enthalpy of neutralization is, 56.012 kJ/mole

Explanation :

First we have to calculate the moles of HCl and NaOH.

$\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=0.400mole/L\times 0.200L=0.08mol$

$\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=0.400mole/L\times 0.200L=0.08mol$

The balanced chemical reaction will be,

$HCl+NaOH\rightarrow NaCl+H_2O$

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.08 mole of HCl neutralizes by 0.08 mole of NaOH

Thus, the number of neutralized moles = 0.08 mole

Now we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = $200mL+200L=400mL$

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 400mL=400g$

Now we have to calculate the heat absorbed during the reaction.

$q=m\times c\times (T_{final}-T_{initial})$

where,

q = heat absorbed = ?

$c$ = specific heat of water = $4.18J/g^oC$

m = mass of water = 400 g

$T_{final}$ = final temperature of water = $27.78^oC=273+25.10=300.78K$

$T_{initial}$ = initial temperature of metal = $25.10^oC=273+27.78=298.1K$

Now put all the given values in the above formula, we get:

$q=400g\times 4.18J/g^oC\times (300.78-298.1)K$

$q=4480.96J$

Thus, the heat released during the neutralization = -4480.96 J

Now we have to calculate the enthalpy of neutralization.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy of neutralization = ?

q = heat released = -4480.96 J

n = number of moles used in neutralization = 0.08 mole

$\Delta H=\frac{-4480.96J}{0.08mole}=-56012J/mole=-56.012kJ/mol$

The negative sign indicate the heat released during the reaction.

Therefore, the enthalpy of neutralization is, 56.012 kJ/mole

8 0

3 years ago

The atomic mass is equal to what?

dsp73

Answer:

The mass number

Explanation:

I hope this helps.

4 0

3 years ago

Read 2 more answers

What are you suppose to do for number 8?

Nadya [2.5K]

Answer:

See the images below

Step-by-step explanation:

To draw a dot diagram of an atom, you locate the element in the Periodic Table and figure out how many valence electrons it has. Then you distribute the electrons as dots around the atom,

a. Silicon.

Si is in Group 14, so it has four valence electrons.

b. Xenon

Xenon is in Group 18, so it has eight valence electrons. We group them as four pairs around the xenon atom.

c. Calcium

Calcium is in Group 2, so it has two valence electrons. They are in a single subshell, so we write them as a pair on the calcium atom.

d. Water

Oxygen is in Group 16, so it has six valence electrons. The hydrogen atoms each contribute one electron, so there are eight valence electrons.

Chemists often use a dash to represent a pair of electrons in a bond.

3 0

3 years ago