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3 years ago

Find the molecular mass of.

Chemistry

2 answers:

dem82 [27]3 years ago

7 0

Answer:

Explanation:

MOLECULAR MASS = ∑ the elements atomic mass from the periodic table

1st NaO

molecular mass = atomic mass of Na + Atomic mass of O

= ( 23 + 16 ) = 39 g/mol

2nd : AlCl3

M.m = atomic mass of Al + Atomic mass of 3Cl

( 27 + 3x35.5 )= 97 g/mole

3rd : Na3(SO4)

M.mass = atomic mass of 3 Na + atomic mass of S + atomic mass of 4 O

( 3x23) + 32 + (4 x 16) =165 g/mol

4th : Mg(OH)2

M.mass = atomic mass of Mg + atomic mass of 2 O + atomic mass of 2

= 24 + 2x16 + 2x1 = 58 g/mol

Margaret [11]3 years ago

3 0

Answer:

sodium oxide Nao
aluminum chloride Al2cl3
sodium sulphate Naso4
magnesium hydroxide Mgoh2

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A sample of n2 effuses in 255 s. how long will the same size sample of cl2 take to effuse?

7nadin3 [17]

For this problem, we use Graham's Effusion Law to find out the rate of effusion of chlorine gas. The formula is as follows:

R₁/R₂ = √(M₂/M₁)

Let 1 be N₂ while 2 be Cl₂

255/R₂ = √(28/70.8)
Solving for R₂,
R₂ = 405.5 s

Thus, it would take 405.5 s to effuse chlorine gas.

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3 years ago

When 20 grams of KCIO3, is dissolved in 100 grams of water, the solution can be

tia_tia [17]

Answer:

b. unsaturated .

Explanation:

Hello there!

In this case, according to the given information, it turns out necessary for us to bear to mind the definition of each type of solution:

- Supersaturated solution: comprises a large amount of solute at a temperature at which it will be able to crystalize upon standing.

- Unsaturated solution: is a solution in which a solvent is able to dissolve any more solute at a given temperature.

- Saturated solution can be defined as a solution in which a solvent is not capable of dissolving any more solute at a given temperature.

In such a way, since 20 grams of the solute are less than the solubility, we infer this is b. unsaturated, as 33.3 grams of solute can be further added to the 100 grams of water.

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3 years ago

Which of the following hazards does not apply for methanol?

AleksAgata [21]

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3 years ago

The density of a 3.37M MgCl2 (FW = 95.21) is 1.25 g/mL. Calulate the molality, mass/mass percent, and mass/volume percent. So fa

Dafna1 [17]

Answer : The molality, mass/mass percent, and mass/volume percent are, 0.0381 mole/Kg, 25.67 % and 32.086 % respectively.

Solution : Given,

Density of solution = 1.25 g/ml

Molar mass of $MgCl_2$ (solute) = 95.21 g/mole

3.37 M magnesium chloride means that 3.37 gram of magnesium chloride is present in 1 liter of solution.

The volume of solution = 1 L = 1000 ml

Mass of $MgCl_2$ (solute) = 3.37 g

First we have to calculate the mass of solute.

$\text{Mass of }MgCl_2=\text{Moles of }MgCl_2\times \text{Molar mass of }MgCl_2$

$\text{Mass of }MgCl_2=3.37mole\times 95.21g/mole=320.86g$

Now we have to calculate the mass of solution.

$\text{Mass of solution}=\text{Density of solution}\times \text{Volume of solution}=1.25g/ml\times 1000ml=1250g$

Mass of solvent = Mass of solution - Mass of solute = 1250 - 320.86 = 929.14 g

Now we have to calculate the molality of the solution.

$Molality=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Mass of solvent}}=\frac{3.37g\times 1000}{95.21g/mole\times 929.14g}=0.0381mole/Kg$

The molality of the solution is, 0.0381 mole/Kg.

Now we have to calculate the mass/mass percent.

$\text{Mass by mass percent}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 100=\frac{320.86}{1250}\times 100=25.67\%$

The mass/mass percent is, 25.67 %

Now we have to calculate the mass/volume percent.

$\text{Mass by volume percent}=\frac{\text{Mass of solute}}{\text{Volume of solution}}\times 100=\frac{320.86}{1000}\times 100=32.086\%$

The mass/volume percent is, 32.086 %

Therefore, the molality, mass/mass percent, and mass/volume percent are, 0.0381 mole/Kg, 25.67 % and 32.086 % respectively.

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3 years ago

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Dmitry_Shevchenko [17]

No, the elements are not always transparent.

Explanation:

The elements become transparent when the light passes through those elements. Transparency is caused because of the transmission and the passing of the light waves through these elements.

But the metals do not become transparent even when the light waves pass through these metals. Metals do not become transparent because the refractive index in them is very big.

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