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3 years ago

How many moles of oxygen will occupy a volume of 2.50 liters?

1 answer:

7 0

Data:
n (number of mols) = ?
V (volume) = 2.50 Liters
If:
1 L → 1000 g
2.50 L → y

y = 1000*2.50 = 2500 g

Therefore:
m (mass) = 2500 g

Now:
Molar Mass (MM) of oxygen = 16 g/mol

Formula:
$n = \frac{m}{MM}$

Solving:
$n = \frac{m}{MM}$
$n = \frac{2500\:\diagup\!\!\!\!\!g}{16\:\diagup\!\!\!\!\!g/mol}$
$\boxed{\boxed{n = 156.25\:mols}}\end{array}}\qquad\quad\checkmark$

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The electrons in the outermost energy level are responsible for the atoms _____. These electrons are called the _______ electron

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3 years ago

____ help scientists understand processes in the natural world by providing simpler representations of those processes.

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3 years ago

In the reaction of aluminum hydroxide and caldium nitrate, how many grams of calcium hydroxide will be formed if 12.55 g of alum

Dahasolnce [82]

Answer:

17.76g

Explanation:

We need to write a balanced chemical equation for the reaction:

2Al(OH)3 + 3Ca(NO3)2 ——> 3Ca(OH)2 + 2Al(NO3)3

In the reaction above, it can be seen that 2 moles of aluminum hydroxide yielded 3 moles of calcium hydroxide. This is the theoretical viewpoint.

Now we need to know what actually happened. We need to calculate the actual number of moles of aluminum hydroxide reacted l. We can get this by dividing the mass by the molar mass.

The molar mass of aluminum hydroxide is 27+ 3( 16+1)

= 27 + 51 = 78g/mol

The number of moles is thus: 12.55/78 = 0.16 moles

Now if 2 moles of aluminum hydroxide gave 3 moles of calcium hydroxide, 0.16moles will give : (0.16*3)/2 = 0.24moles

Now we can calculate the mass of calcium hydroxide formed. The mass of calcium hydroxide formed is the number of moles multiplied by the molar mass.

The molar mass of calcium hydroxide is; 40 + 2(17) = 74g/mol

The mass is thus =74 * 0.24 = 17.76g

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3 years ago

Write the electronic configuration of Cr^2+ (z=24) and predict the number of electrons having n+1 value equal to 3

leonid [27]

Answer:

(a) Cr²⁺: 1s² 2s²2p⁶ 3s²3p⁶ 3d⁴; (b) eight

Explanation:

(a) Electron configuration of Cr

(i). Locate chromium in the Periodic Table.

It's Element 24, so in Period 4, Group 3.

(ii). Write its electron configuration

Remember that Cr is one of those exceptions to the Aufbau principle.

Instead of the predicted electron configuration of [Ar] 4s²3d⁴, we get the configuration [Ar] 4s3d⁵.

The reason is that this this configuration minimizes electron repulsion.

(b) Write the electron configuration for Cr²⁺.

Now, we must remove two electrons from a chromium atom.

The electron in the 4s orbital is removed first, because this orbital is further from the nucleus, making electrons easier to remove.

So, we remove the 4s electron, and then a 3d electron.

The electron configuration of Cr²⁺ is

[Ar]3d⁴ or 1s² 2s²2p⁶ 3s²3p⁶ 3d⁴

(c). Electrons with n + l = 3

The orbitals with n + l = 3 are those covered by the third arrow down in the order of orbital energies:

2p (n = 2, l = 1) and 3s (n = 3, l = 0)

The 2p orbitals can hold six electrons, and the 3s orbital can hold two.

Both subshells are filled in a Cr²⁺ ion, so there are eight electrons

with n+ l = 3.

3 0

3 years ago

A mixture of propane and butane is burned with pure oxygen. The combustion products contain 46.7 mole% H2O. After all the water

wlad13 [49]

Answer:

28%

Explanation:

Basically, all o did was write the equations, balance it and solve for them. Also, at the place I stared, I used simultaneous equation to solve it. Multiplying by 8 and also 3.

It's a pretty straightforward question.

At the final step that's missing, I Did

(y)C3H8 = 2.8 / ( 2.8 + 7.1)

(y)C3H8 = 0.28

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3 years ago