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mr_godi [17]
3 years ago
15

What are the elements in the first period

Chemistry
2 answers:
aliina [53]3 years ago
6 0

Answer:

Explanation:

There are only two elements in the first period: hydrogen and helium. We can explain why there is less elements in the first row in modern theories of atomic structure.

Bond [772]3 years ago
6 0

Answer:

"Hydrogen and Helium". Hydrogen and Helium are the elements of the first period in the modern periodic table.

Explanation:

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Where does photosynthesis occur in a plant cell? In what part of a plant cell does photosynthesis occur?
Lynna [10]

Explanation:

In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll.

3 0
3 years ago
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What is the significance of wanting to know what the pH of a solution is?
balu736 [363]

pH is an important parameter for many reactions to take place in solution and in biological systems. It is related to the concentration of H⁺ ions through the following expression:

pH = 1/[H⁺] = -log [H⁺]

Wanting to know the pH of a solution is equivalent to knowing the amount of hydrogen ions present. But the pH scale is more convenient than the concentration scale because pH usually takes values between 0 and 14.

  • When pH < 7 the solution is acid.
  • When pH = 7 the solution is neutral (like pure water).
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4 0
3 years ago
Mercury orbits the sun at more than ten times the sun speed of Neptune
marysya [2.9K]

Answer: Yes, this is true.

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8 0
3 years ago
A student is given a sample of a blue copper sulfate hydrate. He weighs the sample in a dry covered porcelain crucible and got a
Nata [24]

Answer:

There are present 5,5668 moles of water per mole of CuSO₄.

Explanation:

The mass of CuSO₄ anhydrous is:

23,403g - 22,652g = 0,751g.

mass of crucible+lid+CuSO₄ - mass of crucible+lid

As molar mass of CuSO₄ is 159,609g/mol. The moles are:

0,751g ×\frac{1mol}{159,609g} = 4,7052x10⁻³ moles CuSO₄

Now, the mass of water present in the initial sample is:

23,875g - 0,751g - 22,652g = 0,472g.

mass of crucible+lid+CuSO₄hydrate - CuSO₄ - mass of crucible+lid

As molar mass of H₂O is 18,02g/mol. The moles are:

0,472g ×\frac{1mol}{18,02g} = 2,6193x10⁻² moles H₂O

The ratio of moles H₂O:CuSO₄ is:

2,6193x10⁻² moles H₂O / 4,7052x10⁻³ moles CuSO₄ = 5,5668

That means that you have <em>5,5668 moles of water per mole of CuSO₄.</em>

I hope it helps!

5 0
3 years ago
Which of the following situations indicates an alpha emission?
Angelina_Jolie [31]
Your answer would be C. Alpha decay involves the ejection of 2 protons and 2 neutrons from the nucleus for a total of 4 amu lost. This form of decay is most common in heavy elements.
4 0
3 years ago
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