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4 years ago

If your good at science please help

Chemistry

1 answer:

Nataly [62]4 years ago

3 0

This is biology btw :P arteries carry oxygenized blood away from heart, veins carry deoxygenized blood back to heart, and capillaries are tiny networks of blood vessels that give blood(oxygen) to body tissues

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Electrons are found in energy levels around the nucleus of an atom. Energy levels can also be called ""shells."" The energy leve

melamori03 [73]

Answer:

The first electronic shell or energy level, having n= 1, called the K shell, is the closest to the nucleus.

Explanation:

In an atom, the sub atomic particles called electrons, revolve around the nucleus of the given atom at different energy levels, called shells.

The energy levels or the electronic shells are denoted by the principal quantum number (n) and has the following values n = 1, 2, 3, 4, 5, 6, 7; from the innermost shell to the outermost.

The electron shells are also labelled by the alphabets, K, L, M, N, O, P, and Q, from the innermost shell to the outermost.

Thus the first electronic shell having n= 1, called K shell, is the lowest energy level and is present closest to the nucleus.

Whereas, the last electronic shell having n =7, called Q shell, is the highest energy level and is farthest from the nucleus.

5 0

3 years ago

Un átomo X posee 29 protones y de carga +2 ¿Cuántos electrones tiene?

lesya [120]

Responder:

Explicación:

Dado que:

Número de protones en el átomo X = 29

Carga en el átomo X = +2

Si no hay cargo neto;

número de protones = número de electrones

Sin embargo, dado que el átomo X tiene una carga de +2 (dando 2 electrones).

Por lo tanto,

Número de electrones = número de protones - número de carga en el átomo)

Número de electrones = (29 - 2) = 27

4 0

3 years ago

Which of the following statements describes a difference between a chemical change and a physical change in a substance

siniylev [52]

Explanation:

A physical change is one that alters the physical properties of matter (particularly the form and state).

A chemical change is one in which new kind of matter is formed. It is always accompanied by energy changes (evolution or absorption of energy in form of heat or light or both).

Now, the salient differences between physical and chemical changes;

Physical changes are easily reversible whereas chemical changes are not easily reversible.
Physical changes lead to the production of no new kinds of matter whereas chemical changes leads to the production of new kinds of matter.
Physical changes involves no change in mass whereas chemical changes involves change in mass.
Physical changes require little energy whereas considerable amount of energy is needed for chemical changes.

8 0

3 years ago

A graduated cylinder was filled with water to the 25.0 mL mark and weighed. Its mass was 105.5g. An object made of an unknown me

Marta_Voda [28]

The answer is 8.9 g/mL.

The density (D) is equal to mass (m) divided by volume (V): D = m/V

Let's find the mass of the object:
m = 156 g - 105.5 g = 50.5 g

Let's find the volume of the volume:
V = 30.7 mL - 25 mL = 5.7 mL

The density is:
D = m/V = 50.5 g / 5.7 mL = 8.9 g/mL

6 0

4 years ago

Which organ is found in the excretory system?

Lemur [1.5K]

Answer:

urethra

Explanation:

6 0

3 years ago