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Arturiano [62]
3 years ago
12

If 81g of water is measured out, how many moles are in the sample? *

Chemistry
1 answer:
valkas [14]3 years ago
7 0

Answer:

D

Explanation:

because moles = mass /mr

so 81/18(mr of H2O=2+16)

moles =4.5

hope this helps:)

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Determine the molecular formula for the unknown if the molecular mass is 60.0 amu and the empirical formula is ch2o.
mezya [45]

Answer:

The molecular formule for this unknow molecule is C2H4O2

Explanation:

The empirical formula is CH2O  ( or better said CnH2nOn)

This means there are 3 elements in the formula of this molecule

⇒ Carbon (C) with a Molar mass of 12 g/mole

⇒ Hydrogen (H) with a Molar mass of 1 g/mole

⇒ Oxygen (O) with a Molar mass of 16 g/mole

We can also notice that the amount of hydrogen should 2x the amount of carbon ( also 2x the amount of oxygen).

The mass of the empirical formule = 12g/ mole + 2* 1 g/mole + 16 g/mole = 30 g/mole

To know what number is n in CnH2nOn we should divide the molecular mass by the empirical mass:

60 g/mole / 30g/mole = 2

this means n = 2

and this will give a molecular formule of C2H4O2  

We can control this to calculate the molecular mass:

2*12 + 4* 1 + 2*16 = 24 + 4 + 32 = 60 g/mole

The molecular formule for this unknow molecule is C2H4O2

5 0
4 years ago
What happens when organisms decompose, what happens to carbon
butalik [34]
They can grow fungus and they emit carbon
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What is the molar mass for FeBr3
AleksAgata [21]
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You need to multiply the mass of Br by 3 because there are 3 Bromine atoms. 
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What happens to valence electrons when a covalent bond forms?
abruzzese [7]

Explanation:

Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability

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O. How many protons, neutrons and electrons are in Neodymium - 144 (Nd-144)?
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Diagram of the nuclear composition, electron configuration, chemical data, and valence orbitals of an atom of neodymium-144 (atomic number: 60), an isotope of this element. The nucleus consists of 60 protons (red) and 84 neutrons (orange). 60 electrons (white) successively occupy available electron shells (rings).
8 0
3 years ago
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