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3 years ago

How many atoms of gold are in a pure gold coin weighing 12.0g?

1 answer:

3 0

12.0g x 1 mol / 63.546g = 0.188839581mol

So, for every 1 mole, we have 6.022 x 10^23 of whatever we're measuring. This gives us a conversion factor of (1 mole / 6.022 x 10^23 atoms) or (6.022 x 10^23 atoms / 1 mole).

0.188839581 mol x (6.022 x 10^23 atoms) / 1 mol = 1.137191955 x 10^23

Remember from before that we are limited to 3 significant figures. Since our calculations are complete, we can now round down to: 1.14 x 10^23 

That should be your answer!

Hope it helps!
xo

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Intermolecular forces allow which of the following substances to be the least fluid?

slava [35]

Out of the options, glass is the least fluid. The proof of this also lies in the fact that glass is the most difficult to melt out of all of the mentioned substances, and melting point gives us a rough estimate of the strength of intermolecular forces.

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4 years ago

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Elan Coil [88]

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3 years ago

Reaction Rates

inn [45]

Answer:

PART A 1st order in A and 0th order in B

Part B The reaction rate increases

Explanation:

PART A

The rate law of the arbitrary chemical reaction is given by

$-r_A=k\times\left[A\right]^\alpha\times\left[B\right]^\beta\bigm$

Replacing for the data

Expression 1 $0.00639=k\times{0.12}^\alpha\times{0.22}^\beta$

Expression 2 $0.01280=k\times{0.24}^\alpha\times{0.22}^\beta$

Expression 3 $0.00639=k\times{0.12}^\alpha\times{0.11}^\beta$

Making the quotient between the fist two expressions

$\frac{0.00639}{0.01280}=\left(\frac{0.12}{0.24}\right)^\alpha$

Then the expression for $\alpha$

$\alpha=\frac{ln\frac{0.00639}{0.01280}}{ln\frac{0.12}{0.24}}=1\bigm$

Doing the same between the expressions 1 and 3

$\frac{0.00639}{0.00639}=\left(\frac{0.22}{0.11}\right)^\beta$

Then

$\beta=\frac{ln\frac{0.00639}{0.00639}}{ln\frac{0.22}{0.11}}=0\bigm$

This means that the reaction is 1st order respect to A and 0th order respect to B .

PART B

By the molecular kinetics theory, if an increment in the temperature occurs, the molecules will have greater kinetic energy and, consequently, will move faster. Thus, the possibility of colliding with another molecule increases. These collisions are necessary for the reaction. Therefore, an increase in temperature necessarily produces an increase in the reaction rate.

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3 years ago

Can someone please please help....what will happen to these glands if it go on strike?

sammy [17]

Answer:

World War 3

Explanation:

People will go crazy wife or go to h*** in a become World War 3

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3 years ago

The human body is 0.0040% iron. How many milligrams of iron does a 165 pound person contain?

Fofino [41]

Answer:

in a body of 165 pounds, the iron content is 2993.707 mg

Explanation:

% iron = 0.0040% = (mass iron / mass human) * 100

⇒ mass iron / mass human = 4 E-5

∴ mass human = 165 pounds

⇒ mass iron = 165 pounds * 4 E-5

⇒ mass iron = 6.6 E-3 pounds * ( 453.592 g/pound ) * ( 1000 mg/g )

⇒ mass iron = 2993.707 mg iron

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3 years ago