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Dmitriy789 [7]
3 years ago
14

From 1962 until 1981 pennies were made from 95% copper and 5% zinc and had a mass of 3.1 g. Starting in 1982, pennies have been

made from 97.5% zinc and 2.5% copper and have a mass of 2.5 g. Suppose you have a sample of pennies that consists of 45.4% pre-1982 pennies. Determine the average mass of a penny in this sample.
Chemistry
1 answer:
Sloan [31]3 years ago
8 0

Answer:

2.7724 g

Explanation:

Mass of pre- 1892 pennies = 3.1 g

Abundance = 45.4 %

Mass of post 1892 pennies = 2.5 g

Abundance = 100 - 45.4 = 54.6 %

The average mass is given as = ( 3.1 g   *  45.4 / 100)  +  (2.5g  *  54.6 / 100)

Average Mass = 3.1 * 0.454   +   2.5  *  0.546

Average Mass = 1.4074  + 1.365 = 2.7724 g

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Diffusion is a general term referring to the net movement of atoms and molecules along a concentration gradient, from an area of
aniked [119]

Answer:

Higher concentration to an area of lower concentration

Explanation:

When you open a perfume bottle at a corner of a room, after a while, its fragrance can be perceived across a distance at the other end of the room. This is because, molecules of the compound in the fragrance have moved from the area of higher concentration in the perfume bottle, across a concentration gradient to a region of lower concentration at the other end of the room. This is diffusion.

7 0
3 years ago
Plz help asap What can you conclude about the iron(ii) and iron(iii) ions?
zavuch27 [327]

Answer:

The chemistry of iron is dominated by the +2 and +3 oxidation states i.e. iron(II) and iron(III) complexes e.g. Fe2+ and Fe3+ complex ions with selected ligands, usually of an octahedral shape, a few tetrahedral iron(III) complexes are mentioned too. The reactions of the aqueous ions iron(II) and iron(III) with ammonia, sodium hydroxide and sodium carbonate are described and explained as are complexes of iron(III) with the chloride ion and cyanide ion.

principal oxidation states of iron, redox reactions of iron, ligand substitution displacement reactions of iron, balanced equations of iron chemistry, formula of iron complex ions, shapes colours of iron complexes, formula of compoundsExplanation:

5 0
3 years ago
The limiting reactant in a reaction a. is the reactant for which there is the least amount in grams b. is the reactant which has
Shalnov [3]

Actually the correct answer must be:

The limiting reactant in the reaction is the one which has the lowest ratio of moles available over coefficient in the balanced equation

 

This is because the actual mass or number of moles of the reactant does not directly dictate if it is a limiting reactant, this must be relative to the other reactants.

 

So the answer is:

e. none of the above

5 0
3 years ago
10 atoms of aluminum reacts with 6 molecules of oxygen gas to produce aluminum oxide. 4 Al + 3 O2 ––> 2 Al2O3 What is the exc
Mrrafil [7]

The excess reactant is Aluminum.

<u>Explanation:</u>

We have to write the balanced equation as,

4 Al+ 3 O₂ → 2 Al₂O₃

According to the molar ratio 4: 3, from the given balanced equation, we can say that 4 atoms of Al reacted with 3 molecules of oxygen.

Given that 10 atoms of aluminum reacts with 6 molecules of oxygen, as per the ratio only 8 atoms of Aluminum is required to react with 6 molecules of oxygen, so excess reactant is Aluminum.

8 0
3 years ago
How many lone pairs are around the central atom in the Lewis formula for the
barxatty [35]

Answer:

The answer to your question is None, sulfur share of its electrons

Explanation:

Just remember:

Sulfur, S, has 6 electrons in its outermost shell

Hydrogen, H, has 1 electron in its outermost shell

Oxygen, O, has 6 electrons in its outermost shell

See the picture below

The electrons of sulfur are in blue

The electrons of oxygen are in red

The electron in hydrogen is in yellow

Sulfur is the central atom and it shares all its electrons with the oxygen.

                     

8 0
3 years ago
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