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3 years ago

A compound with the empirical formula ch2 has a molar mass of 98 g/mol what is the molecular formula for this compound ?

1 answer:

7 0

Approximate molecular masses:
Molecular mass of C = 12
Molecular mass of H = 1

Let n = moles required for CH₂.
Then
nCH₂ = 98
n(12 + 2*1) = 98
14n = 98
n = 7

Answer: The molecular formula is 7CH₂

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prisoha [69]

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"A crosslinked copolymer consists of 57 wt% ethylene (C2H4) repeat units and 43 wt% propylene (C3H6) repeat units. Determine the

ch4aika [34]

Explanation:

Percentage ethylene by weight = 57%

Percentage propylene by weight = 43%

Suppose in 100 grams of polymer:

Mass of ethylene = 57 g

Mass of propylene = 43 g

Moles of ethylene = $\frac{57 g}{28 g/mol}=2.036 mol$

Moles of propylene = $\frac{43g}{42g/mol}=1.024 mol$

1 mole = $N_A =6.022\times 10^{23}$ molecules/ atoms

Units of ethylene = $2.036 mol\times N_A$

Units of propylene = $1.024 mol\times N_A$

a) Fraction of ethylene units:

$=\frac{2.036 mol\times N_A}{2.306 mol\times N_A+1.024 mol\times N_A}=\frac{509}{765}$

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Need some help, please. Explain why anions are always larger than the atoms from which they are derived, while cations are alway

ANTONII [103]

The question requires us to explain the differences in radii of neutral atoms, cations and anions.

To answer this question, we need to keep in mind that a neutral atom presents the same number of protons (positive particles) and electrons (negative particles). Another important information is that the protons are located in the nucleus of the atom, while the electrons are around the nucleus. Also, there is an electrostatic force between protons and electrons, which means that they the protons tend to attract the electrons to the nucleus.

While a neutral atom presents the same number of protons and electrons, a cation is an ion with positive charge, which means it has lost one or more electrons. In a cation, the balance between protons and electrons doesn't exist anymore: now, there is more positive than negative charge (more protons than electrons), and the overall attractive force that the protons have for the electrons is increased. As a result, the electrons stay closer to the nucleus and the radius of a cation is smaller than the neutral atom from which it was derived.

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vitfil [10]

Answer:

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blagie [28]

Answer:

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