Please help<br> What is the formula for pentaboron nonahydride?

Consider 2 Al + 6 HCl → 2 AlCl3 + 3 H2 , the reaction of Al with HCl to produce hydrogen gas. What is the pressure of H2 if the

Margaret [11]

Answer : The pressure of hydrogen gas is 8.96 atm.

Explanation :

The given balanced chemical reaction is:

$2Al+6HCl\rightarrow 2AlCl_3+3H_2$

From the balanced chemical reaction we conclude that,

As, 2 moles of Al react to give 3 moles of $H_2$ gas

So, 4.50 moles of Al react to give $\frac{3}{2}\times 4.50=6.75$ moles of $H_2$ gas

Now we have to calculate the moles of $H_2$ gas when percent yield is 75.4.

$\text{The moles of }H_2=75.4\% \times 6.75=\frac{75.4}{100}\times 6.75=5.09moles$

Now we have to calculate the pressure of $H_2$ gas.

Using ideal gas equation :

PV = nRT

where,

P = Pressure of hydrogen gas = ?

V = Volume of the hydrogen gas = 14.0 L

n = number of moles of hydrogen gas = 5.09 moles

R = Gas constant = $0.0821L.atm/mol.K$

T = Temperature of hydrogen gas = 300 K

Putting values in above equation, we get:

$P\times 14.0L=5.09mol\times 0.0821L.atm/mol.K\times 300K\\\\P=8.96atm$

Therefore, the pressure of hydrogen gas is 8.96 atm.

3 0

3 years ago

Man's scientific theories are often in correct because his knowledge is

Alik [6]

Answer:

Incomplete

Explanation:

I wouldn't say that a scientific theory is wrong.

It is the best we have at the time, based on all available knowledge .

As each new discovery is made, scientists modify the theory to fit the new knowledge.

The scientific method is a never-ending process.

8 0

3 years ago

How many core electrons are in a ground state atom of selenium?

Harman [31]

Electrons in an atom can be classified as core electrons and valence electrons. Valence electrons are those electrons which are present in valence shell and participates in bond formation. While, Core electrons are all remaining electrons which are not present in valence shell, hence not take part in bonding.

Atomic number of Selenium (Se) is 34 hence it has 34 electrons with following electronic configuration;

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴

From electronic configuration it is found that the valence shell is 4, and the number of electrons present in valence shell are 6. So,

Core Electrons = Total Electrons - Valence Electrons

Core Electrons = 34 - 6

Core Electrons = 28

Result:
There are 28 core electrons in Selenium.

3 0

4 years ago

What is the empirical formula for a compound that is 31.9% potassium, 28.9% chlorine, and 39.2% oxygen?

notsponge [240]

The empirical formula for a compound is KClO3

Explanation
find the moles of each element
moles = % composition/molar mass

molar mass of of potassium =39g/mol ,chlorine = 35.5 g/mol, oxygen =16 g/mol

moles of potassium = 31.9 / 39 = 0.818 moles
moles of chlorine = 28.9/35.5 = 0.814 moles
moles of oxygen = 39.2/ 16 = 2.45 moles

find the mole ratio by dividing with the smallest mole = 0.814 moles

potassium = 0.818/0.814 =1
chlorine = 0.814/0.814 = 1
oxygen = 2.45 /0.814 =3

the empirical formula is therefore = KClO3

7 0

4 years ago

Which aldehyde is an intermediate in the reduction of ethyl benzoate with lithium aluminum hydride?

garri49 [273]

Answer:

tetrahedral aldehyde

Explanation:

The reaction begins with a hydride nucleophile reacting with the ester carbonyl carbon to form the tetrahedral intermediate.

The carbonyl reforms to produce an aldehyde with the loss of the alkoxide ion.
The resulting aldehyde undergoes a subsequent reaction with a hydride nucleophile to form another tetrahedral intermediate. The carbonyl is not able to reform, because there are no stable leaving groups.
Therefore, the tetrahedral intermediate is protonated to produce a primary alcohol.

6 0

3 years ago

Please help What is the formula for pentaboron nonahydride?