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3 years ago

How many molecules are found in 90 grams of Al(OH)3?

Chemistry

1 answer:

jarptica [38.1K]3 years ago

6 0

Answer:

6.95 x 10²³ molecules/particles

Explanation:

First we need to find the total Empirical Mass. We can find this by adding each element's mass together.

Al = 26.982,

O = 15.999

H = 1.008

26.982 + 3(15.999) + 3(1.008) = 78.003.

Now we divide by the mass given (90 grams).

90/78.003 = 1.153801777.

We then take that number and multiply it by avogadro's number (6.022 x 10²³)

1.153801777 x avogadro's number = 6.95 x 10²³

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What is the empirical formula of a compound that contains 6.10 g of hydrogen and 28 g of nitrogen?

Viktor [21]

Answer:

NH₃

Explanation:

mass H = 6.10 grams

mass N = 28.00 grams

mass cpd = (6.10 + 28.00)grams = 34.10 grams

%H/100wt = (6.10/34.10)100% = 17.9% w/w

%N/100wt = (28.00/34.1)100% = 82.1% w/w

%/100wt => grams/100wt => moles => ratio => reduce => emp ratio

%H/100wt = 17.9% w/w => 17.9g => (17.9/1)moles = 17.9 moles H

%N/100wt = 82.1% w/w => 82.1g => (82.1/14)moles = 5.9 moles N

Ratio N:H => 17.9 : 5.9

Reduce mole ratio (divide by smaller mole value) => 17.9/5.9 : 5.9/5.9

=> 3HY:1H empirical ratio => empirical formula NH₃ (ammonia)

3 0

3 years ago

How many branches of chemistry are there .

faltersainse [42]

Answer:

Explanation:

Analytical chemistry

Organic chemistry

Inorganic chemistry

physical chemistry

Biochemistry

6 0

2 years ago

Read 2 more answers

Which of the following is a possible set of quantum numbers for an electron (n,l,m0,ms) ?

Mashutka [201]

Answer is: (3, 2, 0, -1/2).

The principal quantum number (n) is one of four quantum numbers which are assigned to each electron in an atom to describe that electron's state.

For principal quantum number n=3:

1) azimuthal quantum number (l) can be l = 0...n-1:

l = 0, 1, 2.

The azimuthal quantum number determines its orbital angular momentum and describes the shape of the orbital.

2) magnetic quantum number (ml) can be ml = -l...+l.

ml = -2, -1, 0, +1, +2.

Magnetic quantum number specify orientation of electrons in magnetic field and number of electron states (orbitals) in subshells.

3) the spin quantum number (ms), is the spin of the electron.

ms = +1/2, -1/2.

(1, 1, 0, +1/2) is not correct because orbital quantum number cannot be l = 1 for n = 1.

(2, 1, 2, +1/2) is not correct because magnetic quantum number cannot be ml = 2 for orbital quantum number l = 1.

(3, -2, 1, -1/2) is not correct because orbital quantum number cannot be l = -2 for principal quantum number n = 3.

5 0

3 years ago

9. If 28.56 g of K2O is produced when 25.00 g K is reactedaccording to the following equation, what is the percent yieldof the r

Mumz [18]

Answer

b. 95%

Explanation

Given:

Mass of K₂O produced (actual yield) = 28.56 g

Mass of K that reacted = 25.00 g

Equation: 4K(s) + O₂(g) → 2K₂0(s)

What to find:

The percent yield of K₂O.

Step-by-step solution:

The first step is to calculate the theoretical yield of K₂O produced.

From the balanced equation, 4 mol K produced 2 mol K₂O

Molar mass of K₂O = 94.20 g/mol)

Molar mass of K = 39.10 g/mol)

This means 4 mol x 39.10 g/mol = 156.40 g K produced 2 mol x 94.20 g/mol = 188.40 g K₂O

So 25.00 g K will produce:

$\frac{25.00\text{ }g\text{ }K\times188.40\text{ }g\text{ }K₂O}{156.40\text{ }g\text{ }K}=30.1151\text{ }g\text{ }K₂O$

Actual yield of K₂O = 28.56 g

Theoretical yield of k₂O = 30.1151 g

The percent yield for the reaction can now be calculated using the formula below:

$\begin{gathered} Percent\text{ }yield=\frac{Actual\text{ }yield}{Theoretical\text{ }yield}\times100\% \\ \\ Percent\text{ }yield=\frac{28.56\text{ }g}{30.1151\text{ }g}\times100\% \\ \\ Percent\text{ }yield=0.9484\times100\% \\ \\ Percent\text{ }yield=94.84\%\approx95\% \end{gathered}$

Therefore, the percent yield for the reaction is 95%.

3 0

1 year ago

what is the maximum amount of moles of P2O5 that can theoretically be made from 136 g of P4 and excess oxygen

zhuklara [117]

We are given with
136 g P4
excess oxygen

The complete combustion reaction is
P4 + 5O2 => 2P2O5
Converting the amount of P4 to moles
136/123.9 = 1.098 moles

Using stoichiometry
moles P2O5 = 1.098 x 2 = 2.195 moles P2O5

6 0

3 years ago

Read 2 more answers