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Vikki [24]
3 years ago
12

Had beryllium and calcium already been discovered

Chemistry
1 answer:
Lina20 [59]3 years ago
3 0

Answer:

Yes

Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. ... Notable gemstones high in beryllium include beryl (aquamarine, emerald) and chrysoberyl.

Calcium is a mineral that is necessary for life. In addition to building bones and keeping them healthy, calcium enables our blood to clot, our muscles to contract, and our heart to beat. About 99% of the calcium in our bodies is in our bones and teeth.

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What is the pH of a<br> 2.5 x 10-5 M solution<br> of HCI?
aalyn [17]

Answer:

The pH of the solution is 4.60.

Explanation:

The pH gives us an idea of the acidity or basicity of a solution. More precisely, it indicates the concentration of H30 + ions present in said solution. The pH scale ranges from 0 to 14: from 0 to 7 corresponds to acid solutions, 7 neutral solutions and between 7 and 14 basic solutions. It is calculated as:

pH = -log (H30 +)

pH= -log (2,5 x 10-5)

<em>pH=4.60</em>

7 0
3 years ago
In terms of energy, how would you classify the following chemical reaction?
olga_2 [115]

1. Answer;

- Exothermic reaction

Explanation;

-Exothermic reactions are types of chemical reactions in which heat energy is released to the surroundings. Since enthalpy change is the difference between the energy of products an that of reactants. It means that in an exothermic reaction the energy of products is less than that of products. In this case an energy of 315kJ is released to the surroundings.

2. Answer;

Conserved

-The total amount of energy before and after a chemical reaction is the same. Thus, energy is conserved.

Explanation;

-According to the law of conservation of energy, energy is neither created nor destroyed. Energy may change form during a chemical reaction. For example, energy may change form from chemical energy to heat energy when gas burns in a furnace. However, the exact amount of energy remains after the reaction as before, which is true for all chemical reactions.

3 0
3 years ago
Read 2 more answers
Which statement about Fe is supported by the modern atomic theory but not John Dalton’s theory?
lana66690 [7]

Answer:

The correct option is B

Explanation:

One of the claims of John Dalton's atomic theory is that atom is the smallest unit of matter (which suggests that there are no particles smaller than an atom in any matter). This claim has been disproved by the modern atomic theory which established that there are particles smaller than atom (called subatomic particles). These particles are electrons, protons and neutrons.

One of the modern atomic theory was by Neils Bohr, who proposed that <u>electrons move in circular orbits around the central nucleus</u>. Thus, the electrons of iron can also be said to be present in a region of space (circular path) around the nucleus. This proves that option B is the correct option as John Dalton's theory did not even recognize the electron(s) nor the nucleus.

5 0
3 years ago
Read 2 more answers
5. What is the density of water in g/mL? Why?​
goldfiish [28.3K]

Answer:

1g/ml @ 4 degrees C by definition

Explanation:

7 0
3 years ago
Jennie decides to mix the content of her beaker with another lab group to see “the results.” Is this safe why or why not explain
Ray Of Light [21]

Answer: no

Explanation:

It could be dangerous since you don't know what substance are you adding.it may end up in an explosion

I hope this helps :)

6 0
2 years ago
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