Answer:
1.43 grams
Explanation:
Fe = 55.8 grams Fe = 1 mole Fe
2.56 • 10^-3 moles Fe / 1 • 55.8 grams Fe / 1 mole Fe = 1.43 grams Fe
Basically, you're just multiplying the molar mass of Fe (iron) by the moles of 2.56 • 10^-3 Fe, to find how many grams are in it.
2.56 • 10^-3 moles Fe = 1.43 grams Fe
Answer:
it's answer is lithium and boron.
Step 
<u>find the mass of a single washer</u>
Divide the total mass by the number of washers
Step 
<u>Convert kg to mg</u>
we know that
so
therefore
<u>the answer is</u>
Answer: 122 moles
Procedure:
1) Convert all the units to the same unit
2) mass of a penny = 2.50 g
3) mass of the Moon = 7.35 * 10^22 kg (I had to arrage your numbers because it was wrong).
=> 7.35 * 10^22 kg * 1000 g / kg = 7.35 * 10^ 25 g.
4) find how many times the mass of a penny is contained in the mass of the Moon.
You have to divide the mass of the Moon by the mass of a penny
7.35 * 10^ 25 g / 2.50 g = 2.94 * 10^25 pennies
That means that 2.94 * 10^ 25 pennies have the mass of the Moon, which you can check by mulitiplying the mass of one penny times the number ob pennies: 2.50 g * 2.94 * 10^25 = 7.35 * 10^25.
5) Convert the number of pennies into mole unit. That is using Avogadros's number: 6.022 * 10^ 23
7.35 * 10^ 25 penny * 1 mol / (6.022 * 10^ 23 penny) = 1.22* 10^ 2 mole = 122 mol.
Answer: 122 mol
