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Mazyrski [523]
1 year ago
9

A compound contains 81.1 boron with the remainder being hydrogen what is the empirical formula of the compound

Chemistry
1 answer:
kari74 [83]1 year ago
4 0
Empirical formula is the simplest ratio of whole numbers of components making up the compound
Mass percentage of boron - 81.1 %
Mass percentage of hydrogen - 18.9 %
For 100 g of the compound
                                               B                        H
Mass                                   81.1 g                  18.9 g
Number of moles          81.1 g /11 g/mol       18.9 g/1 g/mol
                                          = 7.37 mol             = 18.9 mol
Divide by the least number of moles
                                           7.37/7.37 =1.00     18.9/7.37 =2.56
Since we get 2.56 that cannot be rounded off we have to multiply both boron and hydrogen values by 2
B = 1.00 x2 = 2.00
H = 2.56 x 2 = 5.12 rounded off to 5
Therefore empirical formula is
B₂H₅

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Neko [114]
There is an exact value for the standard volume at standard conditions of 1 atm and 273 K. This standard volume for any ideal gas is 22.4 L/mol. Thus,

Moles SO₂ = 5.9 L * 1 mol/22.4 L = 0.263 mol

The molar mass for SO₂ is 64.066 g/mol. So, the mass is:

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6 0
2 years ago
The volume of a gas at 7.00°c is 49.0 ml. if the volume increases to 74.0 ml and the pressure is constant, what will the tempera
marshall27 [118]
Using charles law
v1/t1=v2/t2
v1=49ml
v2=74
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t2=?
49/280=74/t2
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0.175t2=74
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8 0
1 year ago
Gaseous cyclobutene undergoes a first-order reaction to form gaseous butadiene. At a particular temperature, the partial pressur
Gnoma [55]

Answer:

41.3 minutes

Explanation:

Since the reaction is a first order reaction, therefore, half life is independent of the initial concentration, or in this case, pressure.

t_{1/2}= \frac{0.693}{K}

So, fraction of original pressure = \frac{1}{2}^2

n here is number of half life

therefore, \frac{1}{8}= \frac{1}{2}^3

⇒ n= 3

it took 124 minutes to drop pressure to 1/8 of original value, half life = 124/3= 41.3 minutes.

8 0
2 years ago
Read 2 more answers
2. A quantity of 1.922g of methanol (CH3OH) was burned in a constant-volume
Cerrena [4.2K]
Mass of methanol (CH3OH) = 1.922 g
Change in Temperature (t) = 4.20°C
Heat capacity of the bomb plus water = 10.4 KJ/oC
The heat absorbed by the bomb and water is equal to the product of the heat capacity and the temperature change.
Let’s assume that no heat is lost to the surroundings. First, let’s calculate the heat changes in the calorimeter. This is calculated using the formula shown below:
qcal = Ccalt
Where, qcal = heat of reaction
Ccal = heat capacity of calorimeter
t = change in temperature of the sample
Now, let’s calculate qcal:
qcal = (10.4 kJ/°C)(4.20°C)
= 43.68 kJ
Always qsys = qcal + qrxn = 0,
qrxn = -43.68 kJ
The heat change of the reaction is - 43.68 kJ which is the heat released by the combustion of 1.922 g of CH3OH. Therefore, the conversion factor is:
5 0
1 year ago
KClKCl has a lattice energy of −701 kJ/mol.−701 kJ/mol. Consider a generic salt, ABAB , where A2+A2+ has the same radius as K+,K
elena-14-01-66 [18.8K]

Explanation:

It is given that lattice energy is -701 kJ/mol.

Whereas it is known that realtion between lattice energy and radius is as follows.

               Lattice energy \propto \frac{Z_{+}Z_{-}}{r}

where,          Z_{+} = +2,    and Z_{-} = -2

Therefore, lattice energy of AB = 4 \times \text{lattice energy of KCl}

                                                    = 4 \times -701 kJ/mol

                                                    = -2804 kJ/mol

Thus, we can conclude that lattice energy of the salt ABAB is -2804 kJ/mol.

6 0
1 year ago
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