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2 years ago

An element with 4 valence electrons in the 3rd period of the periodic table

Chemistry

1 answer:

andrey2020 [161]2 years ago

5 0

Answer:

Silicon (Si) would be the answer

Explanation:

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The weather report says that if the temperature drops 10°, it will reach 25° below zero. The current temperature T can be found

Neporo4naja [7]

Answer:

The current temperature is -15° (15° below zero)

Explanation:

The temperature drops 10°:

T-10°

It will reach 25° below zero:

T - 10° = -25°

We add 10° in both members of the equation:

T - 10° +10° = -25° +10°

The equation is simplified as follows:

T = -25° +10°

T = -15°

The integer -15° can be expressed as 15° below zero.

8 0

3 years ago

Select the correct answer. The wavelength of a given region of the electromagnetic spectrum ranges from 1 x 10-11 - 1 x 10-8 met

Makovka662 [10]

X-rays are found in the given region.

Answer: Option B

<u>Explanation:</u>

The wavelengths of different waves are studied carefully, and their range is determined according to the frequency they exhibited. And based upon the studies, the electromagnetic waves are classified into eight different categories such as gamma, X-, UV, visible, near IR, middle IR, far IR, micro and radio waves.

And each category has different wavelengths and the given radiation falls under X-rays. The wavelength range of X-rays varies from 1 nm to 1 pm. Here, “nm” stands for nano meter and “pm” stands for “pico meter”.

6 0

3 years ago

Your teacher Aaditri sharma has invited you to Classroom: Whip - smart Subject: All subjects of class 4,5,6,7 To join the classr

LUCKY_DIMON [66]

Answer:

well what about the password!!

6 0

3 years ago

The density of pure copper is 8.96 at 20°C. If 5.00 g of pure copper pellets is added to a graduated cylinder containing 14.6 mL

Triss [41]

Answer:

15.2 mL

Explanation:

First we calculate the volume of the copper

$volume = \frac{mass}{density}= \frac{5.00 g}{8.96 g/mL} = 0.5580 mL\\$

when this volume of copper is added to the water, the water level will rise by the level of the volume of copper. So the final volume is:

14.6 mL + 0.5580 mL = 15.158 mL

Since the measuring cylinder is graduated to one decimal place , we can round this up to 15.2 mL

8 0

3 years ago

El pH de una solución acuosa 10^-14 M de ácido acético, a 25°C, es igual a, teniendo en cuenta que Ke = 1.76x10^-5

frez [133]

Answer:

$pH=14$

Explanation:

Hola!

En este caso, consideramos que la disociación de ácido acético ocurre:

$CH_3COOH\rightarrow CH_3COO^-+H^+$

Así, mediante la solución del equilibrio ácido, podemos calcular la concentración de iones hidronio que posteriormente sirven para calcular el pH de la solución, por tal razón, debemos calcular el equilibrio dada la constante de equilibrio y por medio de la ley de acción de masas en términos del cambio $x$ como cualquier problema de equilibrio:

$Ke=\frac{CH_3COO^-][H^+]}{[CH_3COOH]}\\\\1.76x10^{-5}=\frac{x*x}{1x10^{-14}M-x}$

Resolviendo para $x$ , tenemos $x=0.999x10^{-14}$

Así, la concentración de hidrógeno es igual a x, por lo que el pH:

$pH=-log([H^+])=-log(0.999x10^{-14})\\\\pH=14$

Dicho valor tiene sentido desde que la concentración de hidrógeno es casi despreciable, por lo que se puede asumir que tiende a ser básica.

Saludos!

5 0

3 years ago

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