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Harrizon [31]
3 years ago
12

What was helium used for in the past?

Chemistry
2 answers:
yawa3891 [41]3 years ago
6 0
Helium used to be used in hot air balloons.  Then, when the Hindenburg exploded, annexed file, they realized that hydrogen was not only lighter, but it also was less flammable.  

Otrada [13]3 years ago
3 0

Hot air balloons. They have a little hot plate/fire or whatever and they used, and that made the helium rise, thus rising the balloon.
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PLEASE HELPPPP!!! IM BEING TIMED
Mrac [35]

Answer:

B)

Explanation:

This should be the correct answer, lmk if it's not

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2 years ago
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A body moving with a velocity of 20 m/s begins to accelerate at 3 m/s2. How far does the body move in 5 seconds?
Norma-Jean [14]
The distance covered will be:

d = v_0\cdot t + \frac{1}{2}a\cdot t^2 = 20\frac{m}{s}\cdot 5\ s + \frac{5}{2}\frac{m}{s^2}\cdot 5^2\ s^2 = \bf 162,5\ m

The correct answer is D).
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3 years ago
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Write electron configurations for Gallium, Ga (Z=31), and show the total valence electrons
ivann1987 [24]

<u>Answer:</u> The electronic configuration of gallium is written below and number of valence electrons is 3.

<u>Explanation:</u>

Electronic configuration is defined as the representation of electrons around the nucleus of an atom.

Number of electrons in an atom is determined by the atomic number of that atom.

Valence electrons are defined as the electrons present in the outermost shell of an atom.

We are given:

An element Gallium having atomic number as 31.

Number of electrons = 31

Electronic configuration of Gallium is: (Z=31):1s^22s^22p^63s^23p^64s^23d^{10}4p^1

This element has 3 electrons in its outermost shell. So, the number of valence electrons is 3

Hence, the electronic configuration of gallium is written below and number of valence electrons is 3.

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3 years ago
Which of the following will increase entropy in a reaction?
Lapatulllka [165]

B. Heating up the reaction will increase the entropy of a reaction.

<h3>What is entropy?</h3>

Entropy is the measure of the degree of disorderliness of a system.

Entropy is also the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work.

S = ΔH/T

where;

  • S is entropy
  • ΔH is energy input
  • T is  temperature

Entropy increases in reactions in which the total number of product molecules is greater than the total number of reactant molecules.

However, entropy increases as temperature increases. Thus, heating up the reaction will increase the entropy of a reaction.

Learn more about entropy here: brainly.com/question/6364271

#SPJ1

3 0
2 years ago
During an endothermic phase change, what happens to the potential energy and the kinetic energy?
Dovator [93]
The correct answer should be that Potential energy increases, and kinetic energy increases, since they both increase as the temperature changes.
7 0
3 years ago
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