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3 years ago

Why does the atomic radius decrease across a period

1 answer:

4 0

Because the nuclear charge increases across a period and so it has a stronger pull on the outer electrons and will pull in the radius

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What % of all the atoms in the universe are hydrogen

irga5000 [103]

Answer:

Over ninety percent of all the atoms in the Universe are hydrogen atoms.

Explanation:

Over ninety percent of all the atoms in the Universe are hydrogen atoms. By mass, hydrogen makes up about 75% of all matter in the Universe. Hydrogen atoms are also the smallest and lightest of all the atoms with only one electron and one proton in a common single hydrogen atom (called protium).

5 0

4 years ago

How many grams of barium chloride are produced when 1.25 x 1023 molecules of HCl reacts with barium?

sp2606 [1]

Considering the reaction stoichiometry and Avogadro's Number, the mass of barium chloride produced is 21.6 grams.

<h2>Balanced reaction</h2>

The balanced reaction is

2 HCl + Ba → BaCl₂ + H₂

<h2>Moles of HCl that react</h2>

Avogadro's Number is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.

Then you can apply the following rule of three: if 6.023×10²³ molecules are contained in 1 mole of HCl, then 1.25×10²³ molecules are contained in how many moles of HCl?

amount of moles of HCl= (1.25×10²³ molecules × 1 mole)÷ 6.023×10²³ atoms

<u><em>amount of moles of HCl= 0.2075 moles</em></u>

Then, 0.2075 moles of HCl react.

<h2>Reaction stoichiometry</h2>

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

HCl: 2 moles
Ba: 1 mole
BaCl₂: 1 mole
H₂: 1 mole

<h2>Mass of barium chloride produced</h2>

Then you can apply the following rule of three: if by stoichiometry 2 moles of HCl produce 1 mole of BaCl₂, 0.2075 moles of HCl will produce how many moles of BaCl₂?

$amount of moles of BaCl_{2} =\frac{0.2075 moles of HCl x 1 mole of BaCl_{2} }{ 2moles of HCl}$

<u><em>amount of moles of BaCl₂= 0.10375 moles</em></u>

Being the molar mass of BaCl₂ 208.24 g/mole, then the mass of barium chloride produced is calculated as:

$0.10375 molesx\frac{208.24 grams}{1 mole} =21.6 grams$

Finally, the mass of barium chloride produced is 21.6 grams.

Learn more about:

Avogadro's Number

Reaction stoichiometry

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3 years ago

How many elements are there?

svlad2 [7]

Answer:

118 is your answer!

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3 years ago

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What are the most common petrochemical products and their uses?

Rashid [163]

Petrochemicals are separated into 3 groups: Olefins, Aromatics, and Synthesis Gas.

Olefins: Ethelyne (Plastic Products), Propelyne (Plastic Products), and Butadiene (Synthetic Rubber)
Aromatics: Benzene (Dyes), Toluene (Polyurethane), and Xylenes (Synthetic Fibers)
Synthesis Gas: Ammonia (Fertilizer Urea) and Methanol (Chemical intermediate)

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4 years ago

Describe how atoms of a liquid appear compared to a gas

Andrews [41]

Gas are well separated with no regular arrangement. liquid are close together with no regular arrangement. solid are tightly packed, usually in a regular pattern.

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2 years ago