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3 years ago

Which of the following does NOT indicate that a chemical change may have taken place?

Chemistry

1 answer:

Mamont248 [21]3 years ago

4 0

I believe it is phase change because of how that can also happen in a physical change.

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Why is studying light and electrons important for chemistry and understanding the universe?

Brut [27]

Explanation :

The study of light and electrons are important for chemistry & universe.

As we know, everything is made up of particles even light & universe also. The particles are made of atoms and that atoms are made up of electrons, protons & neutrons.

An electron is one of the most important type of subatomic particles. Electrons combine with the proton to form atom. These electrons, protons & neutrons play a vital role in chemistry and universe.

The importance of an electron is that when two atoms react with each other or approach each other, their outermost shells come into contact first and these outermost shells electrons are involved in the chemical reaction.

Also important for chemical reactions, creating bonds, for electricity and the understanding of electrons has allowed for the better understanding of some forces which are in our universe such as electromagnetic force.

We know that the light is act as particle nature and it is a part of universe. As we know that chemists are only responsible for the chemical's study. Chemists cannot study the whole universe that is why they study light and the light is important because nothing would be able to survive.

The studying of light is important for the photoelectric effect, absorption, bio-molecules synthesis, vitamin D synthesis, vision, colors, drying & evaporation, sterilization, solar energy, spectroscopy, signal system and also for electron excitation.

7 0

3 years ago

If you add a solution of NaOH to a solution of H₂CO₃, two reactions occur, one after the other. Write the chemical equations for

Crazy boy [7]

We have a solution of NaOH and H₂CO₃

First, NaOH will dissociate into Na⁺ and OH⁻ ions

The Na⁺ ion will substitute one of the Hydrogen atoms on H₂CO₃ to form NaHCO₃

The H⁺ released from the substitution will bond with the OH⁻ ion to form a water molecule

If there were to be another NaOH molecule, a similar substitution will take place, substituting the second hydrogen from H₂CO₃ as well to form Na₂CO₃

6 0

2 years ago

Erbium (Er) is element 68 on the periodic table. A sample contains 5.04×1023 atoms of Er. Calculate the amount of Er.

Korvikt [17]

Answer:

139.98 g to nearest hundredth.

Explanation:

Using Avogadro's Number:

One mole (167.26 g) of Erbium equates to 6.022141 * 10^23 atoms.

So 5.04 * 10^23 = 167.26 * 5.04/6.022141

= 139,98 g.

3 0

3 years ago

A chemist is looking for an element that reacts similarly to the element lithium (LI). Which would be the best choice?

MatroZZZ [7]

Letter d, because they are both alkali metals (group one)

8 0

3 years ago

Read 2 more answers

PLEASE CAN SOMEONE EXPLAIN this FOR ME WHAT IS RADIOACTIVE ISOTOPES AND ANSWER THIS QUETION? A nitrogen atom has 7 protons and m

zalisa [80]

Answer:

$\frac{15}{7}N$

Explanation:

We already know that the mass number of an atom is the sum of the number of protons and the number of neutrons.

So, the mass number of this isotope is;

Number of protons = 7

Number of neutrons = 8

Mass number = 7 + 8 = 15

Hence, the isotope is;

$\frac{15}{7}N$

3 0

3 years ago