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SashulF [63]
3 years ago
8

Which is the best example of a pure substance?

Chemistry
2 answers:
Luba_88 [7]3 years ago
8 0

Answer:

air

Explanation:

A substance that has a fixed chemical composition throughout is called a pure substance such as water, air, and nitrogen. A pure substance does not have to be of a single element or compound.

iren2701 [21]3 years ago
4 0

Peanuts, or milk please leave like if right

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12. Electrons in the first energy level have the least amount of energy.
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2 years ago
How many grams of h2 will be produced if 175g of HCI are allowed to react completely with sodium
Sedbober [7]

Answer:

4.8 grams of H₂ will be produced if 175g of HCI are allowed to react completely with sodium

Explanation:

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction) you can see that the following amounts in moles of each compound react and are produced:

  • HCl: 2 moles
  • Na: 1 mole
  • NaCl: 2 moles
  • H₂: 1 mole

You know the following masses of each element:

  • H: 1 g/mole
  • Cl: 35.45 g/mole
  • Na: 23 g/mole

So, the molar mass of each compound participating in the reaction is:

  • HCl: 1 g/mole + 35.45 g/mole= 36.45 g/mole
  • Na: 23 g/mole
  • NaCl: 23 g/mole + 35.45 g/mole= 58.45 g/mole
  • H₂: 2* 1 g/mole= 2 g/mole

Then, by stoichiometry of the reaction, the following amounts in grams of each of the compounds participating in the reaction react and are produced:

  • HCl: 2 moles* 36.45 g/mole= 72.9 g
  • Na: 1 mole* 23 g/mole= 23 g
  • NaCl: 2 moles* 58.45 g/mole= 116.9 g
  • H₂: 1 mole* 2 g/mole= 2 g

So, a rule of three applies as follows: if by stoichiometry, when reacting 72.9 grams of HCl 2 grams of H₂ are formed, when reacting 175 grams of HCl how much mass of H₂ will be formed?

mass of H_{2} =\frac{175 g of HCl*2g ofH_{2} }{72.9 g of HCl}

mass of H₂= 4.8 g

<u><em>4.8 grams of H₂ will be produced if 175g of HCI are allowed to react completely with sodium</em></u>

3 0
3 years ago
Read 2 more answers
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