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Flashcards in C3- quantitative chemistry Deck (3)
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1
Q

What is relative formula mass?
Put this into an equation involving mass.
What is the difference between M(small)r and A(small)r?

A

1) RFM is the relative atomic masses of all of the atoms in the molecular formula added together.
2)RFM= mass/number of moles
3)M(small)r= RFM of a compound
RFM of an element

2
Q

A mixture contains 20% iron ions. What mass of FeCl2 would you need to provide to make 50g of the mixture?

A

1) find the mass of iron in the mixture.
50 x 20/100 = 10
2) calculate the percentage mass of iron in iron chloride.
Ar x number of atoms(element)/Mr of the compound x 100
56/56+(2x35.5) x 100 = 44.09%

3
Q

what is the avogadro constant?
what does one mole of carbon weigh?
complete the sentence:
one mole of atoms or _________ of any substance will have a mass (in _____) equal to the relative _______.

A

it is the mass of atoms or molecules of any substance has a mass of grams as the the relative atomic mass Ar(one element)