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3 years ago

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What would you need to know in order to calculate how many pre-1982 pennies and post-1982 pennies are in the mixed sample?

1 answer:

ololo11 [35]3 years ago

8 0

<span>In 1982, the physical composition of the penny was changed; the ratio of the zinc to copper was essentially reversed. As a result, a pre-82 penny has a different density from a post-82 penny. It would help to know several things: first, the average mass and density of both a single pre and post 82 penny. Then you need to know how many pennies in total are in the mixed sample. You would also need to know the mass and density measures of "pure" samples, that is, if we have a mixed sample of 20 pennies, it would be useful to know the mass and density measurements of 20 pre-82 and 20 post-82 pennies. You can then figure out your estimate based on the variances in the density measurements.</span>

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The molar mass of Cr(OH)2 is:

son4ous [18]

The molar mass of $Cr(OH)_2$ is 86.02 g/mole .

<h3><u> Explanation:</u> </h3>

The molar mass of a chemical compound is represented as the mass of a unit of that compound separated by the number of substances in that unit, measured in moles. The molar mass is a volume, not molecular, the property of a substance.

The molar mass is a percentage of various examples of the compound, which usually change in mass due to the appearance of isotopes.

From the below attached table, the Molar mass of $Cr(OH)_2$ is 86.0108 g/mol.

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2 years ago

Help please please please please

Rom4ik [11]

Answer:

D. 18.7 grams

Explanation:

The coefficients are the key.

Create a proportion with them, and the molar mass, and then solve for x:

$\frac{2}{3} = \frac{x}{28} \\ 3x = 2(28) \\ 3x = 56 \\ x = 18.666... = 18.7$

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3 years ago

How are the inner core and outer core diffrent?How are they similar

Sholpan [36]

They are totally different the Inner core is solid and hotter is made of iron, the outer core is liquid the and is made of iron and nickel

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3 years ago

Consider the following reaction where K. = 154 at 298 K: 2NO(g) + Brz(9) 2NOBr(g) A reaction mixture was found to contain 2.69x1

bekas [8.4K]

Explanation:

$2NO(g) + Br_2(g)\rightleftharpoons 2NOBr(g)$

Equilibrium constant of reaction = $K=154$

Concentration of NO = $[NO]=\frac{2.69\times 10^{-2} mol}{1 L}=2.69\times 10^{-2} M$

Concentration of bromine gas = $[Br_2]=\frac{3.85\times 10^{-2} mol}{1 L}=3.85\times 10^{-2} M$

Concentration of NOBr gas = $[Br_2]=\frac{9.56\times 10^{-2} mol}{1 L}=9.56\times 10^{-2} M$

The reaction quotient is given as:

$Q=\frac{[NOBr]^2}{[NO]^2[Br_2]}=\frac{(9.56\times 10^{-2} M)^2}{(2.69\times 10^{-2} M)^2\times 3.85\times 10^{-2} M}$

$Q=328.06$

$Q>K$

The reaction will go in backward direction in order to achieve an equilibrium state.

1. In order to reach equilibrium NOBr (g) must be produced. False

2. In order to reach equilibrium K must decrease. False

3. In order to reach equilibrium NO must be produced. True

4. Q. is less than K . False

5. The reaction is at equilibrium. No further reaction will occur. False

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2 years ago

The volume of a cube is calculated by using the following formula: l x h x w. The length (l), height (h), and width (w) of a met

aliya0001 [1]

Answer:

8.909466637830

Explanation:

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2 years ago