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AVprozaik [17]
2 years ago
7

An atom has atomic number of 34. how many protons and electrons does it have? what is its symbol? 34 protons and electrons. se l

ist the number of

Chemistry
1 answer:
AURORKA [14]2 years ago
4 0
Se: Selenium

Protons: 34
Electrons: All atoms in the periodic table are neutral until changed otherwise
Neutrons: 44
Atomic Mass: 78.09

>Symbol attached<

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You add 7.8 g of iron to 20.70 mL of water and observe that the volume of iron and water together is 21.69 mL . Calculate the de
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21.69mL - 20.70mL = .99mL Fe
7.8 g / .99 mL = 7.9g/mL 
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Why does it take so much heat and pressure to create helium and other elements?
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Answer:

To break down the nucleus of an atom

Explanation:

Remember to change from one element to another, is necessary to add protons, neutrons and electrons,in most of the cases.

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In this way, is a must to have a combination of pressure and heat to destabilize an atom and take some of this subatomic particles.

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According to one acid-base theory, a water molecule acts as an acid when the water molecule
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According to one acid-base theory, a water molecule acts as an acid when the water molecule (3) donates an H+.
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What items are true about a block of ice at -10°C as you continue to apply heat
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1. its temperature will rise continuously until it melts

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What is the molarity of 225 grams of Cu(NO2)2 in a total volume of 2.59 L?
Kay [80]

Answer:

The molarity is 0.56\frac{moles}{L}

Explanation:

In a mixture, the chemical present in the greatest amount is called a solvent, while the other components are called solutes. Then, the molarity or molar concentration is the number of moles of solute per liter of solution.

In other words, molarity is the number of moles of solute that are dissolved in a given volume.

The Molarity of a solution is determined by:

Molarity (M)=\frac{number of moles of solute}{Volume}

Molarity is expressed in units (\frac{moles}{liter}).

Then you must know the number of moles of Cu(NO₂)₂. For that it is necessary to know the molar mass. Being:

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  • N: 14 g/mol
  • O: 16 g/mol

the molar mass of Cu(NO₂)₂ is:

Cu(NO₂)₂= 63.54 g/mol + 2*(14 g/mol + 2* 16 g/mol)= 155.54 g/mol

Now the following rule of three applies: if 155.54 g are in 1 mole of the compound, 225 g in how many moles are they?

moles=\frac{225 g*1 mole}{155.54 g}

moles= 1.45

So you know:

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  • volume=2.59 L

Replacing in the definition of molarity:

Molarity=\frac{1.45 moles}{2.59 L}

Molarity= 0.56\frac{moles}{L}

<u><em>The molarity is 0.56</em></u>\frac{moles}{L}<u><em></em></u>

5 0
3 years ago
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