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3 years ago

If you could please summarise the information in the two screenshots I'll give you brainiest

Chemistry

1 answer:

aleksley [76]3 years ago

4 0

Answer:

Explanation:

A 'mole' is the mass of substance that contains 1 Avogadro's Number of particles of that substance. This is equal to 1 formula weight of the substance. That is when thinking 'moles', think 'how many formula weights are there in the given mass?'

Example.

Given 100 grams of water (H₂O => formula weight = 18 grams/mole) ...

Ask 'how many 18's are there in 100?' => number of moles of H₂O... => 100/18 = 5.555... moles H₂O

This is the same for any substance => how many formula weights are there in the GIVEN mass? Always => #moles.

moles = mass(g)/formula wt(g·mol⁻¹)

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What is subshell and why do we use it if we have main shells already

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3 years ago

The solubility of oxygen gas in water at 40 ∘c is 1.0 mmol/l of solution. What is this concentration in units of mole fraction?

juin [17]

The formula for mole fraction is:

$mole fraction of solute = \frac{number of moles of solute}{total number of moles of solution}$ -(1)

The solubility of oxygen gas = 1.0 mmol/L (given)

1.0 mmol/L means 1.0 mmol are present in 1 L.

Converting mmol to mol:

$1.00 mmol\times \frac{1 mol}{1000 mmol} = 0.001 mol$

So, moles of oxygen = 0.001 mol

For moles of water:

1 L of water = 1000 mL of water

Since, the density of water is 1.0 g/mL.

$Density = \frac{mass}{volume}$

$Mass = 1.0 g/ml\times 1000 mL = 1000 g$

So, the mass of water is 1000 g.

Molar mass of water = 18 g/mol.

Number of moles of water = $\frac{1000 g}{18 g/mol} = 55.55 mol$

Substituting the values in formula (1):

$mole fraction = \frac{0.001}{55.55+0.001}$

$mole fraction = 1.8\times 10^{-5}$

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3 years ago

Select the reason why two molecules of benzaldehyde cannot react via the aldol condensation.

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Answer:

water helps u a lot

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Here's your answer, hope this helps!

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