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3 years ago

TIMED

Chemistry

2 answers:

zhannawk [14.2K]3 years ago

6 0

Density = mass/volume
Density = 81g/0.9cm³
Density = 90g/cm³
: )

Arlecino [84]3 years ago

4 0

Answer : The density of the sample in grams per cubic centimeter is, $90g/cm^3$

Solution : Given,

Mass of unknown sample = 81 g

Volume of unknown sample = $0.9cm^3$

Formula used :

$\text{Density of unknown sample}=\frac{\text{Mass of unknown sample}}{\text{Volume of unknown sample}}$

Now put all the given values in this formula, we get the density of unknown sample.

$\text{Density of unknown sample}=\frac{81g}{0.9cm^3}=90g/cm^3$

Therefore, the density of the sample in grams per cubic centimeter is, $90g/cm^3$

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3 years ago

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Electrolysis

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Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s) + H2O (l) â†’ Ca(OH)2 (s) In a p

dybincka [34]

Answer:

The option closest to the percentage yield is option;

d. 81.1

Explanation:

The given chemical equation of the reaction is presented as follows;

CaO (s) + H₂O (l) → Ca(OH)₂

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The volume of water with which the CaO was reacted = Excess volume of water

Number of moles = Mass/(Molar mass)

The mass of Ca(OH)₂ recovered, actual yield = 2.14 g

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The number of moles of CaO in the reaction, n₁ = 2.00 g/(56.0774 g/mol ≈ 0.036 moles

The molar mass of Ca(OH)₂ = 74.093 g/mol

The number of moles of Ca(OH)₂ in the reaction, n₂ = 2.14 g/(74.093 g/mol) ≈ 0.029 moles

From the given chemical reaction, one mole of CaO reacts with one mole of H₂O to produce one mole of Ca(OH)₂

Therefore, 0.036 moles of CaO will produce 0.036 moles of Ca(OH)₂

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