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lianna [129]
3 years ago
10

How many molecules are in 145.5 grams of Be(OH)2

Chemistry
1 answer:
Zanzabum3 years ago
3 0

Answer:

2.04 x 10²⁴ molecules

Explanation:

Given parameters:

Mass of Be(OH)₂ = 145.5g

To calculate the number of molecules in this mass of Be(OH)₂ we follow the following steps:

>> Calculate the number of moles first using the formula below:

Number of moles = mass/molarmass

Since we have been given the mass, let us derive the molar mass of Be(OH)₂

Atomic mass of Be = 9g

O = 16g

H = 1g

Molar Mass = 9 + 2(16 + 1)

= 9 + 34

= 43g/mol

Number of moles = 145.5/43 = 3.38mol

>>> We know that a mole is the amount of substance that contains Avogadro’s number of particles. The particles can be atoms, molecules, particles etc. Therefore we use the expression below to determine the number of molecules in 3.38mol of Be(OH)₂:

Number of

molecules= number of moles x 6.02 x 10²³

Number of molecules= 3.38 x 6.02 x 10²³

= 20.37 x 10²³ molecules

= 2.04 x 10²⁴ molecules

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2 years ago
If the two atoms participating in a bond have an electron negativity difference of 1.9 , what type of of bond would they be part
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Answer:

Polar covalent bond.

Explanation:

When the bond is formed between the atoms by sharing the electrons the bond thus have covalent character.   The atom with larger electronegativity attract the electron pair more towards it self and becomes partial negative while the other atom becomes partial positive.  When the electronegativity difference is less than 0.4 the bond is non polar covalent.

When bonded atoms have greater electronegativity difference i.e 2 or greater than two the bond is ionic because electron is transfer from low electronegative atom to highest electronegative atom.

For example:

In water the electronegativity of oxygen is 3.44 and hydrogen is 2.2. That's why electron pair attracted more towards oxygen, thus oxygen becomes partial negative and hydrogen becomes partial positive.

In case of H₂, Cl₂, Br₂ the bond has very high covalent character because of zero electronegativity difference.

7 0
3 years ago
2.2 Chromium has four naturally-occurring isotopes: 4.34% of 50Cr, with an atomic weight of 49.9460 amu; 83.79% of 52Cr, with an
shutvik [7]

Answer:

Average atomic mass  = 51.9963 amu

Explanation:

Given data:

Abundance of Cr⁵⁰ with atomic mass= 4.34% ,  49.9460 amu

Abundance of Cr⁵² with atomic mass = 83.79%,  51.9405 amu

Abundance of Cr⁵³ with atomic mass =9.50%,  52.9407 amu

Abundance of Cr⁵⁴ with atomic mass  = 2.37%,   53.9389 amu

Average atomic mass = 51.9963 amu

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass +....n)  / 100

Average atomic mass  = (4.34×49.9460)+(83.79×51.9405) +(9.50×52.9407)+ (2.37×53.9389) / 100

Average atomic mass =  216.7656 + 4352.0945 + 502.9367 +127.8352 / 100

Average atomic mass  = 5199.632 / 100

Average atomic mass  = 51.9963 amu

4 0
3 years ago
Consider a sample of helium and a sample of neon, both at 30.0°C and 1.5 atm. Both samples have a volume of 5.0 liters. Which st
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Answer:

A.

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Using the ideal gas equation, we can calculate the number of moles present. I.e

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Since all the parameters are equal for both gases, we can simply deduce that both has the same number of moles of gases.

The relationship between the mass of each sample and the number of moles can be seen in the relation below :

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Now , we have established that both have the same number of moles. For them to have the same mass, they must have the same molar masses which is not possible.

Hence option A is wrong

7 0
3 years ago
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