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2 years ago

Nitrogen gas effuses through an opening 1.59 times faster than an unknown gas.

1 answer:

5 0

A) Nitrogen has an ATOMIC mass number of 14, but nitrogen gas consists of N₂ molecules, so the mass to use in this problem is 28 g/mol. Rates of effusion ∝ 1/√(mass), so

√(mass unknown) /√28 = (rate N₂ effusion)/(rate unknown effusion) = 1.59 
∴ mass unknown = (1.59)²(28) = 70.78 g/mol 

B) One possible gas that comes close for this mass is NF₃.

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What is the density of ammonia (NH3) at 293 K and 0.913 atm?

Anastaziya [24]

Answer: The density of Ammonia is 0.648 g/l

Explanation:

Density = Mass/ Volume

Mass of one mole of Ammonia (NH3) = 17.031g

Volume =?

Using the ideal gas law we can determine the volume.

PV = nRT

P = 0.913 atm, V= ?, n = 1, R = 0.08206 L.atm/K, and T= 293K

Make V the subject of the formular, we then have;

V= nRT/ P = 1 mol x 0.08206 L.atm/ K.mol x 293 / 0.913 atm

V = 24.04358/ 0.913 = 26.3L

Having gotten the value of Volume in this question, we then go back to solve for density.

Density = Mass/ Volume

17.031g/ 26.3L = 0.64756 ≈ 0.648 g/l

7 0

2 years ago

Making solutions is an extremely important component to real-life chemistry. If you make 3.00 L of a solution using 90.0 g of so

kumpel [21]

Answer:

Final concentration of NaOH = 0.75 M

Explanation:

For $NaOH$ :-

Given mass = 90.0 g

Molar mass of NaOH = 39.997 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{90.0\ g}{39.997\ g/mol}$

$Moles\ of\ NaOH= 2.2502\ mol$

Molarity is defined as the number of moles present in one liter of the solution. It is basically the ratio of the moles of the solute to the liters of the solution.

The expression for the molarity, according to its definition is shown below as:

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

Where, Volume must be in Liter.

It is denoted by M.

Given, Volume = 3.00 L

So,

$Molarity=\frac{2.2502\ mol}{3.00\ L}=0.75\ M$

Final concentration of NaOH = 0.75 M

5 0

2 years ago

Which of the following compounds contains the Lead (II) ion? PbO PbCl4 Pb2O Pb2S

KATRIN_1 [288]

PbO Let's look at each of the 4 compounds and see what's needed. PbO. * Oxygen has a valance shell that's missing 2 electrons and wants to get those 2 elections. Lead donates them, so you have a Lead (II) ions. This is a correct choice. PbCl4 * Chlorine wants to grab 1 electron to fill it's valance shell and Lead donates that election. However, there's 4 chlorine atoms and every one of them wants and electron, and lead is donating all 4 of the desired electrons making the Lead (IV) ion. So this is a bad choice. Pb2O * Oxygen still wants 2 electrons and gets them from the lead. But there's 2 lead atoms and each of them donates 1 election making for 2 Lead(I) ions. So this too is a bad choice. Pb2S * Sulfur is in the same column of the periodic table as oxygen and if this compound were to exist would have similar properties as Pb2O and would have Lead(I) ions. So this is a bad choice.

6 0

2 years ago

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Which three groups of the periodic table contain the most elements classified as metalloids (semimetals)?

attashe74 [19]

The metalloids are mostly concentrated in groups 14, 15, and 16. (Some simpler charts will show them as 4A, 5A, and 6A - take a look at the top of the periodic table your class uses to double-check).

If you like my answer, please vote me a 'brainliest' - trying to improve my rank :-)

8 0

2 years ago

Read 2 more answers

Explain the relationship between the relative size of an ion and its neutral atom and the charge on the ions

mars1129 [50]

A cation (+) will be smaller than its neutral atom, while anion (-) will be larger than its neutral atom.

3 0

2 years ago