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  TomateSupra7536

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  Secondary IV • 3yr.

  Hello!

  I was wondering, is there a particular order in the periodic table? Because from left to right and from top to bottom the number in the box starts from 1 and goes up, but does this number mean something or is it a reference number that has been set randomly? Thanks for your time :))

  Chemistry

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  1 answer
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  TomateSupra7536

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  Secondary IV • 3yr.

  Hi!

  I was reviewing and trying to remember how to find the number of protons, electrons and neutrons in an atom? (I will put an example below) Thank you !!!

  
  

  $$ _{92}^{235}U $$

  Chemistry

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  1 answer
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  SkillfulGrasshopper3789

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  Secondary V • 3yr.

  How do I answer this question: how many moles of oxygen are there in 2.25 g of CO2? Thank you!

  Chemistry

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  1 answer
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  SkillfulGrasshopper3789

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  Secondary IV • 3yr.

  Ok, I understand that in an acid-base neutralization, we mix an acid and a base in a solution, but I don't understand how the pH becomes neutral again after ...? Can you explain this to me please?

  Chemistry

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  1 answer
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  SkillfulGrasshopper3789

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  Secondary IV • 3yr.

  Hello again :)

  Ok if I have a solution where I have to use colorimetric indicators, how do I use several at the same time to know the pH approximately? Do I simply combine them?

  
  

  thank you

  Chemistry

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  1 answer
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  SkillfulGrasshopper3789

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  Secondary IV • 3yr.

  Hi!

  If a solution is alkaline, is it acidic or basic? Thanksss

  Chemistry

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  1 answer
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  SkillfulGrasshopper3789

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  Secondary IV • 3yr.

  Hi again!

  What does “ph is measured on a logarithmic scale” mean ????

  Chemistry

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  2 answers
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  SkillfulGrasshopper3789

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  Secondary IV • 3yr.

  hi!

  
  

  Why can several pH indicators be used in an experiment? How can the appropriate one be determined? Thank you :))

  Chemistry

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  1 answer
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  FairTangerine2097

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  Secondary IV • 3yr.

  Hello,

  Could you explain to me what the molar mass is? I can't quite understand.

  Thank you so much!

  Chemistry

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  1 answer
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  FairTangerine2097

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  Secondary IV • 3yr.

  Helloo, what is the difference between a mole and the Avogadro number?

  Thank you!

  Chemistry

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  FairTangerine2097

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  Secondary IV • 3yr.

  Hello,

  I have trouble differentiating between exothermic and endothermic reactions according to their enthalpies. Do you have any tips or summaries?

  Chemistry

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  1 answer
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  FairTangerine2097

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  Secondary IV • 3yr.

  Hello,

  I am having difficulty understanding how the thermal energy formula works. Could you explain to me, please?

  Thank you so much!

  Chemistry

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  1 answer