I’m so lostttt, please someone help explain this to me. ;(
Use this information to answer the questions below. Be sure your answers have the correct number of significant digits.
What is the mass of 1 mole of pennies?
How many moles of pennies have a mass equal to the mass of the moon? Write your answer as a decimal, and round to one place?
4 Answers
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1 mole of anything contains 6.02 * 10^23 somethings.
1 mole of pennies = 6.02 *10^23 pennies
Mass = 6.02 10^23 pennies 2.50 grams / penny = 1.51 * 10^24 grams
1 mole of pennies has a mass of 1.51 * 10^24 grams =
1.51 10 ^24 grams [ 1 kg / 1000 grams ] = 1.51 *10^21 kg
1 mole of pennies = 1.51 * 10^21 kg
x mole of pennies = 7.35 * 10^22 kg (I think).
x = 7.36 10 ^22 kg / 1.51 10^21 = 48.8 moles of pennies to 3 places = the mass of the moon.
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Mass Of Penny
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Since the mass of the penny is 2.5 grams, it is a penny manufactured on or after 1982 and it is almost 100% zinc.
EDITED TO ADD:
The Mass of the Moon,is 7.35 x 10^22 kilograms or 7.35 x 10^25 grams. (Always remember to watch those units).
A mole of pennies is 6.023 x 10^23 pennies and would weigh 6.023 x 10^23 • 2.5 or
1.51 x 10^24 grams.
The mass of the Moon is 7.35 x 10^25 grams divided by 1.51 x 10^24 grams per mole of pennies =
48.81 moles of pennies to equal the Moon’s mass.
Now to round those answers:
mass of a mole of pennies = 1.5 x 10 x 10^24 grams.
48.8 moles of pennies = the mass of the Moon.
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Well the mass of one mole of pennys is just the mass of ‘one’ penny times the amount a ‘mole’ represents, a mole is 6.02^23.
So, 2.50g x 6.02^23 = 1.505^24 g
That is the mass of one mole of pennys. Now, divide the moons mass by the mass of one mole of pennys.
7.35^22g / 1.505^24g = .04883 = 4.88^(-2)
Both numbers for the pennys mass and moons mass had 3 significant figures so that is why the answer was put in standard notation.
