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2 years ago

What are periods on the periodic table? How many are there?

1 answer:

8 0

A period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one beginning at the far left. A new period begins when a new principal energy level begins filling with electrons. Period 1 has only two elements (hydrogen and helium), while periods 2 and 3 have 8 elements.

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Which of these is the best example of translational motion?

Dima020 [189]

The answer would b B, a leaf blowing across a field.
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2 years ago

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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

2 years ago

Fill in the blank, please help. (55 points)

Degger [83]

The answer would be evaporation takes place at the surface of an ocean, lake, stream, or other body of water

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2 years ago

An ideal gas in a cylindrical container of radius r and height h is kept at constant pressure p. The bottom of the container is

Juli2301 [7.4K]

Answer:

$m =\frac{p*(pi)*r^{2}*h*mw}{R*\frac{T_{1} + T_{O}}{2}}$

Explanation:

The gas ideal law is

PV= nRT (equation 1)

Where:

P = pressure

R = gas constant

T = temperature

n= moles of substance

V = volume

Working with equation 1 we can get

$n =\frac{PV}{RT}$

The number of moles is mass (m) / molecular weight (mw). Replacing this value in the equation we get.

$\frac{m}{mw} =\frac{PV}{RT}$ or

$m =\frac{P*V*mw}{R*T}$ (equation 2)

The cylindrical container has a constant pressure p

The volume is the volume of a cylinder this is

$V =(pi)*r^{2}*h$

Where:

r = radius

h = height

(pi) = number pi (3.1415)

This cylinder has a radius, r and height, h so the volume is $V =(pi)*r^{2}*h$

Since the temperatures has linear distribution, we can say that the temperature in the cylinder is the average between the temperature in the top and in the bottom of the cylinder. This is:

$T =\frac{T_{1} + T_{O}}{2}$

Replacing these values in the equation 2 we get:

$m =\frac{P*V*mw}{R*T}$ (equation 2)

$m =\frac{p*(pi)*r^{2}*h*mw}{R*\frac{T_{1} + T_{O}}{2}}$

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3 years ago

can you help me with #7? #7 says "A substance enters into and is altered through the course of a chemical change. it is called a

Zigmanuir [339]

Reactant hope this helps

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3 years ago

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